U.S. patent application number 16/951420 was filed with the patent office on 2021-03-11 for metallic porous membrane, classifying method using the same, and classifying device.
The applicant listed for this patent is Murata Manufacturing Co., Ltd.. Invention is credited to Masaru Banju, Makoto Hasegawa, Takashi Kondo, Tamio Mizukami, Junko Watanabe.
Application Number | 20210071132 16/951420 |
Document ID | / |
Family ID | 1000005226021 |
Filed Date | 2021-03-11 |
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United States Patent
Application |
20210071132 |
Kind Code |
A1 |
Kondo; Takashi ; et
al. |
March 11, 2021 |
METALLIC POROUS MEMBRANE, CLASSIFYING METHOD USING THE SAME, AND
CLASSIFYING DEVICE
Abstract
A metallic porous membrane that classifies cell aggregates
includes a membrane section having a first principal surface for
capturing the cell aggregates, a second principal surface opposing
the first principal surface, and a plurality of through-holes
communicating with the first principal surface and the second
principal surface.
Inventors: |
Kondo; Takashi;
(Nagaokakyo-shi, JP) ; Banju; Masaru;
(Nagaokakyo-shi, JP) ; Watanabe; Junko;
(Nagaokakyo-shi, JP) ; Hasegawa; Makoto;
(Nagaokakyo-shi, JP) ; Mizukami; Tamio;
(Nagaokakyo-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Murata Manufacturing Co., Ltd. |
Nagaokakyo-shi |
|
JP |
|
|
Family ID: |
1000005226021 |
Appl. No.: |
16/951420 |
Filed: |
November 18, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16114454 |
Aug 28, 2018 |
10889796 |
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16951420 |
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PCT/JP2017/008145 |
Mar 1, 2017 |
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16114454 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C12M 47/04 20130101;
B01D 39/20 20130101; B01D 39/10 20130101; B01D 2239/1208 20130101;
G01N 1/28 20130101; G01N 15/0272 20130101; G01N 2015/0053 20130101;
G01N 2015/0065 20130101 |
International
Class: |
C12M 1/00 20060101
C12M001/00; G01N 15/02 20060101 G01N015/02; B01D 39/10 20060101
B01D039/10; B01D 39/20 20060101 B01D039/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2016 |
JP |
2016-055475 |
Sep 5, 2016 |
JP |
2016-172839 |
Claims
1. A metallic porous membrane that classifies cell aggregates, the
metallic porous membrane comprising: a membrane section including a
first principal surface for capturing the cell aggregates, a second
principal surface opposing the first principal surface, and a
plurality of through-holes communicating with the first principal
surface and the second principal surface, wherein an opening ratio
of a first area of the plurality of through-holes at the first
principal surface to a projected entire area of the first principal
surface is no less than 10%, and some of the plurality of
through-holes are configured to have different dimensions
sufficient to release pressure applied to the metallic porous
membrane without degrading classification accuracy of the metallic
porous membrane.
2. The metallic porous membrane according to claim 1, wherein the
first principal surface of the membrane section is flat, and the
plurality of through-holes each communicate through a wall surface
continuously connecting a first opening on the first principal
surface side of the membrane section and a second opening on the
second principal surface side of the membrane section.
3. The metallic porous membrane according to claim 1, wherein a
width of the through-hole is less than 100% of a size of the cell
aggregate.
4. The metallic porous membrane according to claim 1, wherein a
width of the through-hole is less than 80% of a size of the cell
aggregate.
5. The metallic porous membrane according to claim 1, wherein a
width of the through-hole is no less than 20% of a size of the cell
aggregate.
6. The metallic porous membrane according to claim 1, wherein a
width of the through-hole is no less than 40% of a size of the cell
aggregate.
7. A classifying method that classifies cell aggregates, the method
comprising: preparing a metallic porous membrane having a membrane
section including a first principal surface for capturing the cell
aggregates, a second principal surface opposing the first principal
surface, and a plurality of through-holes communicating with the
first principal surface and the second principal surface, wherein
an opening ratio of a first area of the plurality of through-holes
at the first principal surface to a projected entire area of the
first principal surface is no less than 10%, and some of the
plurality of through-holes are configured to have different
dimensions sufficient to release pressure applied to the metallic
porous membrane without degrading classification accuracy of the
metallic porous membrane; and classifying the cell aggregates by
passing a liquid containing the cell aggregates through the
metallic porous membrane and capturing the cell aggregates on the
metallic porous membrane.
8. The classifying method according to claim 7, wherein, the
preparing of the metallic porous membrane includes preparing a
plurality of metallic porous membranes respectively including
through-holes having mutually different dimensions, and arranging
the plurality of metallic porous membranes in series from an
upstream side of a flow path through which a liquid containing the
cell aggregates flows in a descending order of the dimensions of
the through-holes of the plurality of metallic porous
membranes.
9. The classifying method according to claim 8, wherein, in the
classifying of the cell aggregates, cells isolated from the cell
aggregates are allowed to pass through the metallic porous membrane
positioned at a lowermost stage from among the plurality of
metallic porous membranes.
10. The classifying method according to claim 9, further comprising
subculturing the isolated cells.
11. The classifying method according to claim 7, further
comprising: washing the cell aggregates when the cell aggregates
are captured on the metallic porous membrane.
12. The classifying method according to claim 7, further
comprising: collecting the cell aggregates captured by the metallic
porous membrane.
13. The classifying method according to claim 7, further comprising
sterilizing the metallic porous membrane.
14. The classifying method according to claim 7, further
comprising: determining medicine efficacy using the classified cell
aggregates.
15. The classifying method according to claim 7, wherein a flow
path in which the liquid containing the cell aggregates flows while
passing through the metallic porous membrane is shut off from
outside air.
16. A classifying device that classifies cell aggregates, the
classifying device comprising: a first metallic porous membrane
provided with a membrane section including a first principal
surface for capturing the cell aggregates, a second principal
surface opposing the first principal surface, and a plurality of
through-holes communicating with the first principal surface and
the second principal surface, wherein an opening ratio of a first
area of the plurality of through-holes at the first principal
surface to a projected entire area of the first principal surface
is no less than 10%, and some of the plurality of through-holes are
configured to have different dimensions sufficient to release
pressure applied to the metallic porous membrane without degrading
classification accuracy of the metallic porous membrane.
17. The classifying device according to claim 16, further
comprising: a plurality of metallic porous membranes respectively
including through-holes having mutually different dimensions,
wherein the plurality of metallic porous membranes are arranged in
series from an upstream side of a flow path through which a liquid
containing the cell aggregates flows in a descending order of the
different dimensions of the through-holes of the plurality of
metallic porous membranes.
18. The classifying device according to claim 17, wherein the
dimension of the through-holes of a metallic porous membrane
positioned at a lowermost stage among the plurality of metallic
porous membranes, is equal to or smaller than the size of cells to
be isolated from the cell aggregates.
19. The classifying device according to claim 17, wherein the
dimension of the through-holes of a metallic porous membrane
positioned at a lowermost stage among the plurality of metallic
porous membranes have a size that allows cells to be isolated from
the cell aggregates to pass through.
20. The classifying device according to claim 16, further
comprising: a housing that encompasses the metallic porous membrane
and includes a fluid introducing path that opposes the first
principal surface of the metallic porous membrane and a fluid
discharging path that opposes the second principal surface of the
metallic porous membrane.
21. The classifying device according to claim 16, wherein a flow
path in which a liquid containing the cell aggregates flows while
passing through the metallic porous membrane is shut off from
outside air.
22. The classifying device according to claim 16, wherein the
metallic porous membrane is sterilized.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 16/114,454, filed Aug. 28, 2018, which is a
continuation of International application No. PCT/JP2017/008145,
filed Mar. 1, 2017, which claims priority to Japanese Patent
Application No. 2016-055475, filed Mar. 18, 2016, and Japanese
Patent Application No. 2016-172839, filed Sep. 5, 2016, the entire
contents of each of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to metallic porous membranes
for classifying cell aggregates, and classifying methods as well as
classifying device using the stated metallic porous membranes.
BACKGROUND OF THE INVENTION
[0003] In medicine efficacy research or the like using cell
aggregates (spheroids), cell aggregates having a uniform dimension
are required.
[0004] For example, Patent Document 1 discloses that cell
aggregates are classified using a filter. [0005] Patent Document 1:
Japanese Unexamined Patent Application Publication No.
2015-62400
SUMMARY OF THE INVENTION
[0006] Recently, in the classification of cell aggregates using a
filter, it has been requested to increase a collection rate of the
cell aggregates.
[0007] An object of the present invention is to provide a metallic
porous membrane capable of increasing a collection rate of cell
aggregates, and a classifying method as well as a classifying
device using the stated metallic porous membrane.
[0008] A metallic porous membrane according to an aspect of the
present invention that classifies cell aggregates includes a
membrane section having a first principal surface for capturing the
cell aggregates, a second principal surface opposing the first
principal surface, and a plurality of through-holes communicating
with the first principal surface and the second principal
surface.
[0009] A classifying method according to an aspect of the present
invention that classifies cell aggregates includes preparing a
metallic porous membrane provided with a membrane section including
a first principal surface for capturing the cell aggregates, a
second principal surface opposing the first principal surface, and
a plurality of through-holes communicating with the first principal
surface and the second principal surface; and classifying the cell
aggregates, by passing a liquid containing the cell aggregates
through the metallic porous membrane and capturing the cell
aggregates on the metallic porous membrane.
[0010] A classifying device according to an aspect of the present
invention that classifies cell aggregates includes a metallic
porous membrane provided with a membrane section including a first
principal surface for capturing the cell aggregates, a second
principal surface opposing the first principal surface, and a
plurality of through-holes communicating with the first principal
surface and the second principal surface.
[0011] According to the aspects of the present invention, a
metallic porous membrane capable of increasing a collection rate of
cell aggregates, and a classifying method as well as a classifying
device using the stated metallic porous membrane can be
provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is an enlarged perspective view illustrating part of
a membrane section of a metallic porous membrane in a first
embodiment according to the present invention.
[0013] FIG. 2 is a schematic diagram illustrating part of the
membrane section of the metallic porous membrane in FIG. 1 when
viewed in a thickness direction thereof.
[0014] FIG. 3 is a cross-sectional view taken by cutting along an
A-A line in FIG. 2.
[0015] FIG. 4 is a schematic diagram illustrating a configuration
of a classifying device of the first embodiment according to the
present invention.
[0016] FIG. 5 is a perspective view illustrating a housing of the
classifying device of the first embodiment according to the present
invention.
[0017] FIG. 6 is a perspective view in which a cross section of
part of the housing in FIG. 5 is illustrated.
[0018] FIG. 7 is a flowchart of a classifying method of the first
embodiment according to the present invention.
[0019] FIG. 8 is a photograph showing a liquid containing cell
aggregates having different sizes.
[0020] FIG. 9 is a photograph obtained by image-capturing part of a
metallic porous membrane having captured cell aggregates in an
enlarged manner in a first working example.
[0021] FIG. 10 is a photograph obtained by image-capturing part of
a nylon mesh having captured cell aggregates in an enlarged manner
in a first comparative example.
[0022] FIG. 11 is a photograph obtained by image-capturing an
intersecting portion of the nylon mesh of the first comparative
example in an enlarged manner.
[0023] FIG. 12 is a photograph showing a liquid containing cell
aggregates of different dimensions.
[0024] FIG. 13 is an enlarged photograph of cell aggregates
collected by an uppermost metallic porous membrane in a second
working example.
[0025] FIG. 14 is an enlarged photograph of cell aggregates
collected by a center metallic porous membrane in the second
working example.
[0026] FIG. 15 is an enlarged photograph of cell aggregates
collected by a lowermost metallic porous membrane in the second
working example.
[0027] FIG. 16 is a photograph obtained by image-capturing part of
a liquid after having passed through the uppermost metallic porous
membrane in an enlarged manner in the second working example.
[0028] FIG. 17 is a photograph obtained by image-capturing part of
a liquid after having passed through the center metallic porous
membrane in an enlarged manner in the second working example.
[0029] FIG. 18 is a photograph obtained by image-capturing part of
a liquid after having passed through the lowermost metallic porous
membrane in an enlarged manner in the second working example.
[0030] FIG. 19 is a photograph obtained by image-capturing part of
cultured cell aggregates in an enlarged manner in a third working
example.
[0031] FIG. 20 is an enlarged photograph of cell aggregates
captured by an uppermost metallic porous membrane in the third
working example.
[0032] FIG. 21 is an enlarged photograph of cell aggregates
captured by a center metallic porous membrane in the third working
example.
[0033] FIG. 22 is an enlarged photograph of cell aggregates
captured by a lowermost metallic porous membrane in the third
working example.
[0034] FIG. 23 is a photograph obtained by image-capturing part of
a liquid after having passed through the lowermost metallic porous
membrane in an enlarged manner in the third working example.
[0035] FIG. 24 is a graph showing a measurement result of ATP
active mass with respect to a diameter of a cell aggregate in the
third working example.
[0036] FIG. 25 is a photograph of a group of cell aggregates
captured by a metallic porous membrane with a hole size being 180
.mu.m in the third working example.
[0037] FIG. 26 is a photograph of a group of cell aggregates
captured by a metallic porous membrane with a hole size being 100
.mu.m in the third working example.
[0038] FIG. 27 is a photograph of a group of cell aggregates
captured by a metallic porous membrane with a hole size being 58
.mu.m in the third working example.
[0039] FIG. 28 is a photograph of a cell aggregate produced by
culturing three cell aggregates shown in FIG. 25 captured by the
uppermost metallic porous membrane in the third working
example.
[0040] FIG. 29 is a photograph of a cell aggregate produced by
culturing three cell aggregates shown in FIG. 26 captured by the
center metallic porous membrane in the third working example.
[0041] FIG. 30 is a photograph of a cell aggregate produced by
culturing three cell aggregates shown in FIG. 27 captured by the
lowermost metallic porous membrane in the third working
example.
[0042] FIG. 31 is a graph showing a measurement result of ATP
active mass of cell aggregates having been cultured for 24 hours
after the input of Bortezomib in the amounts of 1, 3, 10, 20, and
100 nM, respectively, in a fourth working example.
[0043] FIG. 32 is a graph showing a measurement result of ATP
active mass of cell aggregates having been cultured for 48 hours
after the input of Bortezomib in the amounts of 1, 3, 10, 20, and
100 nM, respectively, in the fourth working example.
[0044] FIG. 33 is a graph showing a measurement result of ATP
active mass of cell aggregates having been cultured for 24 hours
after the input of Bortezomib in the amounts of 1, 3, 10, 20, and
100 nM, respectively, in a second comparative example.
[0045] FIG. 34 is a graph showing a measurement result of ATP
active mass of cell aggregates having been cultured for 48 hours
after the input of Bortezomib in the amounts of 1, 3, 10, 20, and
100 nM, respectively, in the second comparative example.
[0046] FIG. 35 is a diagram illustrating a culturing state of cells
66 in a fifth working example and a third comparative example.
[0047] FIG. 36 is a graph showing a measurement result of an RLU
light emission amount (ATP active mass) of cultured cells in the
fifth working example and the third comparative example.
[0048] FIG. 37 is a photograph obtained by image-capturing part of
cultured cell aggregates in an enlarged manner in a sixth working
example.
[0049] FIG. 38 is an enlarged photograph of cell aggregates
captured by an uppermost metallic porous membrane in the sixth
working example.
[0050] FIG. 39 is an enlarged photograph of cell aggregates
captured by a center metallic porous membrane in the sixth working
example.
[0051] FIG. 40 is an enlarged photograph of cell aggregates
captured by a lowermost metallic porous membrane in the sixth
working example.
[0052] FIG. 41 is a photograph obtained by image-capturing part of
a liquid after having passed through the lowermost metallic porous
membrane in an enlarged manner in the sixth working example.
[0053] FIG. 42 is a graph showing a measurement result of ATP
active mass with respect to a diameter of a cell aggregate in the
sixth working example.
[0054] FIG. 43 is a photograph of a group of cell aggregates
captured by a metallic porous membrane with a hole size being 180
.mu.m in the sixth working example.
[0055] FIG. 44 is a photograph of a group of cell aggregates
captured by a metallic porous membrane with a hole size being 100
.mu.m in the sixth working example.
[0056] FIG. 45 is a photograph of a group of cell aggregates
captured by a metallic porous membrane with a hole size being 58
.mu.m in the sixth working example.
[0057] FIG. 46 is a photograph of a cell aggregate produced by
culturing three cell aggregates shown in FIG. 43 captured by the
uppermost metallic porous membrane in the sixth working
example.
[0058] FIG. 47 is a photograph of a cell aggregate produced by
culturing three cell aggregates shown in FIG. 44 captured by the
center metallic porous membrane in the sixth working example.
[0059] FIG. 48 is a photograph of a cell aggregate produced by
culturing three cell aggregates shown in FIG. 45 captured by the
lowermost metallic porous membrane in the sixth working
example.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0060] (Reasons for Conceiving the Present Invention)
[0061] In the case where medicine efficacy against cancer is
researched, a cell aggregate is used as a model of a cancer cell,
for example. Cancer cells have different sizes depending on the
degree of advancement of cancer. Further, medicines effective
against cancer differ depending on a difference in size of the
cancer cells. For example, a medicine effective against early-stage
cancer, small cancer tissue, or the like exhibits a small effect
against advanced cancer, large cancer tissue, or the like in some
case. Because of this, in medicine efficacy research using cell
aggregates, if the medicine efficacy research is carried out using
cell aggregates of different dimensions, a variation is generated
in the medicine efficacy data. Accordingly, to suppress the
variation in the medicine efficacy data, it is required to obtain
cell aggregates having a uniform dimension.
[0062] Further, as for cell aggregates, they are typically used as
tissue for regenerative medicine. In this case, although tissue
having a desired size is needed, it is difficult to produce tissue
having the desired size by devising a production method for cell
aggregates. As such, it is more efficient to produce cell
aggregates of various sizes and thereafter select the tissue of the
desired size. Accordingly, it is required to select desired tissue
with high efficiency.
[0063] As a method for adjusting the dimension of cultured cell
aggregates to a desired dimension, for example, a method for
classifying cell aggregates is used in which the cell aggregates
having the desired dimension are captured using a filter made of a
membrane, a nylon mesh, or the like. However, using the
above-described filter raises a problem that a collection rate of
the cell aggregates becomes low because dimension accuracy of the
cell aggregates that can be captured is low. As such, the inventors
of the present invention have conceived the invention as follows so
as to solve the above problems.
[0064] A metallic porous membrane according to an embodiment of the
present invention that classifies cell aggregates includes a
membrane section having a first principal surface for capturing the
cell aggregates, a second principal surface opposing the first
principal surface, and a plurality of through-holes communicating
with the first principal surface and the second principal
surface.
[0065] With this configuration, the collection rate of the cell
aggregates can be increased.
[0066] In the metallic porous membrane, the first principal surface
of the membrane section may be formed to be flat, and the plurality
of through-holes may each communicate through a wall surface
continuously connecting an opening on the first principal surface
side of the membrane section and an opening on the second principal
surface side thereof.
[0067] With this configuration, the collection rate of the cell
aggregates can be further increased.
[0068] In the above metallic porous membrane, the width of the
through-hole may be less than 100% of the size of the cell
aggregate.
[0069] With this configuration, the desired cell aggregates can be
captured with certainty.
[0070] In the above metallic porous membrane, the width of the
through-hole may be less than 80% of the size of the cell
aggregate.
[0071] With this configuration, the desired cell aggregates can be
captured with certainty even if the cell aggregates are
deformed.
[0072] In the above metallic porous membrane, the width of the
through-hole may be no less than 20% of the size of the cell
aggregate.
[0073] This configuration makes it easy for a fluid that is not a
capturing target to pass through, and consequently makes it
possible to shorten a working time.
[0074] In the above metallic porous membrane, the width of the
through-hole may be no less than 40% of the size of the cell
aggregate.
[0075] This configuration makes it easier for a fluid that is not a
capturing target to pass through, and consequently makes it
possible to shorten the working time.
[0076] A classifying method for cell aggregates according to an
embodiment of the present invention includes preparing a metallic
porous membrane provided with a membrane section including a first
principal surface for capturing the cell aggregates, a second
principal surface opposing the first principal surface, and a
plurality of through-holes communicating with the first principal
surface and the second principal surface; and classifying the cell
aggregates by passing a liquid containing the cell aggregates
through the metallic porous membrane and capturing the cell
aggregates on the metallic porous membrane.
[0077] With this configuration, the collection rate of the cell
aggregates can be increased.
[0078] In the preparing of the metallic porous membrane in the
classifying method, a plurality of metallic porous membranes
respectively including through-holes having mutually different
dimensions may be prepared, and the stated plurality of metallic
porous membranes may be arranged in series from an upstream side of
a flow path, through which a liquid containing the cell aggregates
flows, in the descending order of the dimensions of the
through-holes thereof.
[0079] With this configuration, the cell aggregates of the desired
dimensions can be efficiently obtained in a stepwise manner.
[0080] In the classifying of the cell aggregates in the classifying
method, isolated cells isolated from the cell aggregates may be
allowed to pass through the metallic porous membrane positioned at
the lowermost stage from among the plurality of metallic porous
membranes.
[0081] With this configuration, a liquid not containing the cell
aggregates but containing the isolated cells can be obtained.
[0082] The above-discussed classifying method may further include
subculturing the isolated cells having passed through the metallic
porous membrane positioned at the lowermost stage.
[0083] This configuration makes it possible for the isolated cells
contained in the liquid having passed through the lowermost
metallic porous membrane to be moved to a new culture medium and
cultured therein. Alternatively, the isolated cells can also be
used for forming cell aggregates again.
[0084] The above-discussed classifying method may further include
washing the cell aggregates in a state of the stated cell
aggregates being captured on the metallic porous membrane.
[0085] With this configuration, the classified cell aggregates can
be washed with ease.
[0086] The classifying method may further include collecting the
cell aggregates captured on the metallic porous membrane.
[0087] With this configuration, the classified cell aggregates can
be collected with ease.
[0088] In the preparing of the metallic porous membrane in the
classifying method, a sterilized metallic porous membrane may be
prepared.
[0089] This configuration makes it possible to prevent the cell
aggregates from being contaminated by bacterial adhering to the
metallic porous membrane before the classification.
[0090] In the above-discussed classifying method, the flow path in
which the liquid containing the cell aggregates flows while passing
through the metallic porous membrane may be shut off from the
outside air.
[0091] This configuration makes it possible to prevent the cell
aggregates from being contaminated by the outside air.
[0092] A classifying device for cell aggregates according to an
embodiment of the present invention includes a metallic porous
membrane provided with a membrane section including a first
principal surface for capturing the cell aggregates, a second
principal surface opposing the first principal surface, and a
plurality of through-holes communicating with the first principal
surface and the second principal surface.
[0093] With this configuration, the collection rate of the cell
aggregates can be increased.
[0094] In the classifying device, a plurality of metallic porous
membranes respectively including through-holes having mutually
different dimensions may be provided, and the stated plurality of
metallic porous membranes may be arranged in series from an
upstream side of a flow path, through which a liquid containing the
cell aggregates flows, in the descending order of the dimensions of
the through-holes thereof.
[0095] This configuration makes it possible to efficiently obtain
the cell aggregates of the desired dimensions in the stepwise
manner.
[0096] In the classifying device, the dimension of the
through-holes of the metallic porous membrane positioned at the
lowermost stage among the plurality of metallic porous membranes
may be smaller than the size of the isolated cells isolated from
the cell aggregates.
[0097] This configuration makes it possible to restrict the cell
aggregates captured by the lowermost metallic porous membrane.
[0098] In the classifying device, the dimension of the
through-holes of the metallic porous membrane positioned at the
lowermost stage among the plurality of metallic porous membranes
may be a size that can allow the isolated cells isolated from the
cell aggregates to pass through.
[0099] With this configuration, a liquid not containing the cell
aggregates but containing the isolated cells can be obtained.
[0100] The above-discussed classifying device may further be
provided with a housing that encompasses the metallic porous
membrane and includes a fluid introducing path provided so as to
oppose the first principal surface of the metallic porous membrane
as well as a fluid discharging path provided so as to oppose the
second principal surface of the metallic porous membrane.
[0101] This configuration makes it possible to maintain the
metallic porous membrane with ease and perform the classification
at a high collection rate.
[0102] In the classifying device, the flow path in which the liquid
containing the cell aggregates flows while passing through the
metallic porous membrane may be shut off from the outside air.
[0103] This configuration makes it possible to prevent the cell
aggregates from being contaminated by the outside air.
[0104] In the classifying device, the metallic porous membrane may
be sterilized.
[0105] This configuration makes it possible to prevent the cell
aggregates from being contaminated by bacterial adhering to the
metallic porous membrane before the classification.
[0106] Hereinafter, a first embodiment according to the present
invention will be described with reference to the accompanying
drawings. Note that in the drawings, constitutive elements are
illustrated in an exaggerated manner to assist with explanation
thereof.
First Embodiment
[0107] [Metallic Porous Membrane]
[0108] FIG. 1 is an enlarged perspective view illustrating part of
a metallic porous membrane 10 in a first embodiment according to
the present invention. In FIG. 1, X, Y, and Z directions represent
a longitudinal direction, a lateral direction, and a thickness
direction of the metallic porous membrane 10, respectively. As
illustrated in FIG. 1, the metallic porous membrane 10 is provided
with a membrane section 11 that includes a first principal surface
PS1 and a second principal surface PS2 opposing each other, and
also includes a plurality of through-holes 12 passing through both
the principal surfaces. The metallic porous membrane 10 is a
plate-like structure (lattice-like structure) in which the
plurality of through-holes 12 are provided at constant intervals in
matrix form in the membrane section 11. The metallic porous
membrane 10 is a metallic thin film configured to classify cell
aggregates by passing a liquid containing a plurality of cell
aggregates having different dimensions therethrough.
[0109] In the present specification, "cell aggregate" means
aggregate mass of cells formed by a plurality of cells being
bonded. The cell aggregate is, for example, a cell aggregate using
cancerous cells, liver cells, iPS cells, or the like.
[0110] Although FIG. 1 does not illustrate the whole of the
metallic porous membrane 10, the metallic porous membrane 10 is,
for example, a circular metal mesh in the first embodiment.
Dimensions of the metallic porous membrane 10 are, for example, 7.8
mm in diameter and 20 .mu.m in thickness. A material configuring
the metallic porous membrane 10 may be gold, silver, copper,
platinum, nickel, stainless steel, palladium, titanium, or an alloy
of these metals. In particular, as the material of the metallic
porous membrane 10, gold, nickel, stainless steel, or titanium is
preferable from the standpoint of a biological affinity for cell
aggregates. The metallic porous membrane 10 is not limited to a
circular shape, and may be formed in a rectangular shape such as a
rectangle, square or the like, or a shape such as an oval or the
like.
[0111] FIG. 2 is a schematic diagram illustrating part of the
membrane section 11 of the metallic porous membrane 10 when viewed
in the thickness direction (Z direction). As shown in FIG. 2, the
plurality of through-holes 12 are periodically arranged on the
first principal surface PS1 and the second principal surface PS2 of
the membrane section 11. To be specific, the plurality of
through-holes 12 are provided in the membrane section 11 at equal
intervals in matrix form. The plurality of through-holes 12 are
each formed in a square shape when viewed from the first principal
surface PS1 side of the metallic porous membrane, in other words,
when viewed in the Z direction. The plurality of through-holes 12
are provided at the equal intervals in two arrangement directions
parallel to the sides of the square, in other words, arranged at
the equal intervals in the X direction and the Y direction in FIG.
2. The through-holes 12 are not limited to a square shape, and may
be formed in a shape such as a rectangle, circle, or oval. The
arrangement of the holes are not limited to tetragonal lattice
arrangement, and may be rectangle arrangement in which intervals in
two arrangement directions are unequal in the case of square
arrangement, triangle lattice arrangement, quasi-periodic
arrangement, or the like, for example.
[0112] The shape and dimensions of the through-holes 12 should be
appropriately designed in accordance with the size and shape of the
cell aggregates. In the first embodiment, the through-hole 12 is
formed in, for example, a square shape when viewed from the first
principal surface PS1 side of the membrane section 11 of the
metallic porous membrane 10, that is, when viewed in the Z
direction; one side d thereof is designed to be less than 100% of
the size of the cell aggregates. It is preferable that the one side
d be designed to be less than 80% of the size of the cell
aggregates, whereby the cell aggregates can be captured with
certainty even if they are deformed during being filtered. Further,
causing the one side d to be no less than 20% of the size of the
cell aggregates makes it easy for a fluid that is not a capturing
target to pass through, and consequently makes it possible to
shorten the working time. It is more preferable to make the one
side d be no less than 40% of the size of the cell aggregates,
which makes it easier for the fluid to pass through. It is
preferable for a lattice interval b between the through-holes 12 to
be larger than one time (1X) the one side d of the through-hole 12
and no more than 10 times (10X) the one side d thereof, and is more
preferable to be no more than three times (3X) the one side d of
the through-hole 12, for example. Alternatively, it is preferable
to be no less than 10% in terms of an opening ratio. The opening
ratio is calculated by the division of (an area occupied by the
through-holes 12)/(a projected entire area of the first principal
surface PS1 including the area occupied by the through-holes 12).
The through-holes 12 are not limited to a square shape, and may be
formed in a shape such as a circle, oval, rectangle, or rhombus. In
the first embodiment, although the dimension of the square
through-hole 12 is explained using the one side d, the dimension of
the through-hole 12 may be defined with a width of the through-hole
12. In the case where the through-hole 12 has a square shape, the
width of the through-hole 12 corresponds to a line segment
connecting two sides opposing each other, where a distance between
the opposing two sides becomes longest. In the case where the
through-hole 12 has a circular shape (including an oval shape), the
width of the through-hole 12 corresponds to the diameter
thereof.
[0113] The metallic porous membrane 10 includes the plurality of
through-holes 12 having the same size. Here, "same size" means that
a variation in dimension of the plurality of through-holes 12 falls
within a range of .+-.5 .mu.m. Some of the plurality of
through-holes 12 may be formed having different dimensions. For
example, in order to release pressure applied to the metallic
porous membrane 10, some of the plurality of through-holes 12 may
be formed having a larger dimension than that of the other
through-holes to the extent that classification accuracy is not
degraded.
[0114] In the present specification, when cell aggregates are
disposed in a liquid and observed under a microscope, of lines
respectively connecting two arbitrary points on an outer
circumference of each cell aggregate in a two-dimensional
observation image, the longest line is defined as a length of the
cell aggregate, and an average value of the lengths of three or
more capturing target cell aggregates is defined as a "size of the
cell aggregate".
[0115] FIG. 3 is a cross-sectional view illustrating part of the
membrane section 11 of the metallic porous membrane 10 taken by
cutting along an A-A line in FIG. 2. As shown in FIG. 3, the
through-hole 12 communicates through a wall surface continuously
connecting an opening on the first principal surface PS1 side of
the membrane section 11 and an opening on the second principal
surface PS2 side thereof. To be specific, the through-hole 12 is so
provided that the opening on the first principal surface PS1 side
can be projected on the opening on the second principal surface PS2
side. That is, in the case where the metallic porous membrane 10 is
viewed from the first principal surface PS1 side, in other words,
viewed in the Z direction, the through-hole 12 is so provided that
the opening on the first principal surface PS1 side overlaps with
the opening on the second principal surface PS2 side. In a
preferred embodiment, the through-hole 12 is so provided that an
inner wall thereof is perpendicular to the first principal surface
PS1 and the second principal surface PS2. The size of the opening
on the first principal surface PS1 side and the size of the opening
on the second principal surface PS2 side may differ from each
other.
[0116] Further, in the metallic porous membrane 10, the first
principal surface PS1 of the membrane section 11 where the cell
aggregates are captured is formed to be flat. That is, the first
principal surface PS1 of the membrane section 11 is formed flush,
and uneven portions in the Z direction are substantially not
formed. In addition, the second principal surface PS2 of the
membrane section 11 is also formed to be flat. Further, it is
preferable for profile irregularity of both the principal surfaces
of the membrane section 11 to be smaller than the size of the
isolated cell. This is because it can be reduced that the isolated
cells adhere to both the principal surfaces of the membrane section
11.
[0117] [Classifying Device]
[0118] A classifying device according to the first embodiment of
the present invention will be described with reference to FIG. 4.
FIG. 4 is a schematic diagram illustrating a configuration of a
classifying device 50 according to the first embodiment.
[0119] As shown in FIG. 4, the classifying device 50 is provided
with a plurality of metallic porous membranes 10A, 10B, and 10C.
The plurality of metallic porous membranes 10A, 10B, and 10C are
arranged in series in a direction 70 in which a liquid 60
containing cell aggregates 61a, 61b, 61c and isolated cells 62
flows. In the first embodiment, the metallic porous membranes 10A,
10B, and 10C are disposed in that order from an upstream side in a
flow path through which the liquid 60 flows. In other words, in the
classifying device 50, the metallic porous membrane 10A is disposed
at the uppermost stage, the metallic porous membrane 10B is
disposed at the center stage, and the metallic porous membrane 10C
is disposed at the lowermost stage. Further, the metallic porous
membranes 10A, 10B, and 10C are disposed so that each first
principal surface PS1 thereof is orthogonal to the direction 70 in
which the liquid 60 flows.
[0120] In the first embodiment, the cell aggregates 61a, 61b, and
61c are cell aggregates having mutually different dimensions. The
cell aggregate 61a has a larger dimension than the cell aggregate
61b, and the cell aggregates 61b has a larger dimension than the
cell aggregate 61c. In other words, of the cell aggregates 61a,
61b, and 61c, the cell aggregate 61a is largest while the cell
aggregate 61c is smallest.
[0121] In the present specification, an "isolated cell" refers to
one cell that forms a cell aggregate and is in an independent state
in which it does not adhere to the cell aggregate. In other words,
the "isolated cell" means a cell isolated from the cell aggregate.
Alternatively, the "isolated cell" means an isolated cell that has
not been involved in forming the cell aggregate. In the first
embodiment, the dimension of the isolated cell 62 is smaller than
the dimension of each of the cell aggregates 61a, 61b, and 61c.
[0122] Through-holes 12a, 12b, and 12c having mutually different
dimensions are respectively provided in membrane sections 11a, 11b,
and 11c of the metallic porous membranes 10A, 10B, and 10C. The
through-hole 12a has a larger dimension than the through-hole 12b,
and the through-hole 12b has a larger dimension than the
through-hole 12c. In other words, of the through-holes 12a, 12b,
and 12c, the through-hole 12a has the largest dimension while the
through-hole 12c has the smallest dimension.
[0123] The through-hole 12a of the metallic porous membrane 10A is
designed with a dimension that does not allow the cell aggregate
61a to pass through but allows the cell aggregates 61b, 61c and the
isolated cell 62 to pass through. Specifically, the through-hole
12a is designed with the dimension smaller than the cell aggregate
61a and larger than the cell aggregate 61b. Because of this, in the
case where the liquid 60 containing the cell aggregates 61a, 61b,
61c and the isolated cells 62 is filtered by passing through the
metallic porous membrane 10A, the cell aggregates 61a cannot pass
through the through-holes 12a and are captured on the first
principal surface PS1 of the metallic porous membrane 10A. That is,
the cell aggregates 61a larger than the dimension of the
through-holes 12a are captured on the first principal surface PS1
of the metallic porous membrane 10A. On the other hand, the cell
aggregates 61b, 61c and the isolated cells 62 contained in the
liquid 60 can pass through the through-holes 12a. Because of this,
a liquid (filtrate) 60A after being filtered by the metallic porous
membrane 10A contains the cell aggregates 61b, 61c and the isolated
cells 62, but does not contain the cell aggregates 61a.
Accordingly, with the metallic porous membrane 10A, the cell
aggregates 61a can be classified from the liquid 60 containing the
cell aggregates 61a, 61b, 61c and the isolated cells 62.
[0124] The through-hole 12b of the metallic porous membrane 10B is
designed with a dimension that does not allow the cell aggregate
61b to pass through but allows the cell aggregate 61c and the
isolated cell 62 to pass through. Specifically, the through-hole
12b is designed with the dimension smaller than the cell aggregate
61b and larger than the cell aggregate 61c. Because of this, in the
case where the liquid 60A having been filtered by the metallic
porous membrane 10A is filtered by passing through the metallic
porous membrane 10B, the cell aggregates 61b cannot pass through
the through-holes 12b and are captured on the first principal
surface PS1 of the metallic porous membrane 10B. On the other hand,
the cell aggregates 61c and the isolated cells 62 contained in the
liquid 60A can pass through the through-holes 12b. Because of this,
a liquid (filtrate) 60B after being filtered by the metallic porous
membrane 10B contains the cell aggregates 61c and the isolated
cells 62, but does not contain the cell aggregates 61b.
Accordingly, with the metallic porous membrane 10B, the cell
aggregates 61b can be classified from the liquid 60A containing the
cell aggregates 61b, 61c and the isolated cells 62.
[0125] The through-hole 12C of the metallic porous membrane 10C is
designed with a dimension that does not allow the cell aggregate
61c to pass through but allows the isolated cell 62 to pass
through. Specifically, the through-hole 12c is designed with the
dimension smaller than the cell aggregate 61c and larger than the
isolated cell 62. Because of this, in the case where the liquid 60B
having been filtered by the metallic porous membrane 10B is
filtered by passing through the metallic porous membrane 10C, the
cell aggregates 61c cannot pass through the through-holes 12c and
are captured on the first principal surface PS1 of the metallic
porous membrane 10C. On the other hand, the isolated cells 62
contained in the liquid 60B can pass through the through-holes 12c.
Because of this, a liquid (filtrate) 60C after being filtered by
the metallic porous membrane 10C contains the isolated cells 62,
but does not contain the cell aggregates 61c. Accordingly, with the
metallic porous membrane 10C, the cell aggregates 61c can be
classified from the liquid 60B containing the cell aggregates 61c
and the isolated cells 62.
[0126] The isolated cells 62 contained in the liquid (filtrate) 60C
after being filtered by the metallic porous membrane 10C can be
subcultured. Alternatively, they can be used for producing other
cell aggregates.
[0127] As discussed above, in the classifying device 50, the
plurality of metallic porous membranes 10A, 10B, and 10C are
arranged in series from the upstream side of the flow path, through
which the liquid 60 flows, in the descending order of the
dimensions of the through-holes 12a, 12b, and 12c thereof. This
configuration makes it possible to classify the cell aggregates
having the desired dimensions in the stepwise manner from the
liquid 60 containing the cell aggregates 61a, 61b, 61c and the
isolated cells 62 having mutually different dimensions.
[0128] The classifying device 50 may be provided with a housing for
holding the metallic porous membranes 10A, 10B, and 10C. In this
case, the classifying device 50 filters out filtering target
objects contained in a fluid, having been introduced through a
fluid introducing path, by the metallic porous membranes 10A, 10B,
and 10C housed in the housing in which the fluid introducing path
and a fluid discharging path are provided, and discharges the fluid
having passed through the above metallic porous membranes from the
fluid discharging path.
[0129] FIG. 5 is an exploded perspective view illustrating a
general structure of a housing 20 for holding the metallic porous
membrane 10A, and FIG. 6 is an exploded cross-sectional view
thereof. Note that in FIGS. 5 and 6, the metallic porous membrane
10A is not illustrated.
[0130] As shown in FIGS. 5 and 6, the housing 20 includes a first
housing section 21 formed in a substantially cylindrical shape and
a second housing section 22 also formed in a substantially
cylindrical shape.
[0131] The first housing section 21 includes a fluid introducing
path 21a that is so provided as to oppose the first principal
surface PS1 of the metallic porous membrane 10A. The first housing
section 21 is integrally formed with a first frame member 51
pinching an outer circumference portion of the metallic porous
membrane 10A. In other words, the first frame member 51 is
configured as part of the first housing section 21. An inner
diameter of the first frame member 51 is 6.0 mm, for example.
[0132] On the periphery of the first frame member 51 of the first
housing section 21, there is formed a flange section 21b extending
in a direction intersecting with (for example, orthogonal to) an
extension direction of the fluid introducing path 21a. A plurality
of through-holes 21c are formed in the flange section 21b passing
through in a thickness direction of the flange section 21b. In the
first embodiment, the plurality of through-holes 21c of four are
formed at an interval of 90 degrees. The thickness of the flange
section 21b is, for example, 2.1 mm. The diameter of the
through-hole 21c is, for example, 1.42 mm. The length of the
through-hole 21c is, for example, 0.9 mm.
[0133] The second housing section 22 includes a fluid discharging
path 22a that is so provided as to oppose the second principal
surface PS2 of the metallic porous membrane 10A. The second housing
section 22 is integrally formed with a second frame member 52
pinching the outer circumference portion of the metallic porous
membrane 10A. In other words, the second frame member 52 is
configured as part of the second housing section 22. An inner
diameter of the second frame member 52 is 6.0 mm, for example.
[0134] On the periphery of the second frame member 52 of the second
housing section 22, there is formed a flange section 22b extending
in a direction intersecting with (for example, orthogonal to) the
extension direction of the fluid discharging path 22a. A plurality
of projections 22c are formed on the flange section 22b projecting
in the thickness direction of the flange section 22b. In the first
embodiment, the plurality of projections 22c of four are formed at
an interval of 90 degrees. The diameter of the projection 22c is,
for example, 1.4 mm. The height of the projection 22c is, for
example, 0.9 mm.
[0135] The first housing section 21 and the second housing section
22 are so configured as to be fitted to each other by the plurality
of projections 22c being inserted into the plurality of
through-holes 21c. By the first housing section 21 and the second
housing section 22 being fitted to each other, the outer
circumference portion of the metallic porous membrane 10A is held
between the first frame member 51 and the second frame member
52.
[0136] The housing 20 can be used while being attached to a
luer-lock type syringe (not illustrated), for example. In this
case, it is sufficient to provide a ridge or the like, capable of
being connected with the luer-lock type syringe, to at least one of
a terminal end portion 21d (upper end portion in FIG. 6) of the
first housing section 21 and a terminal end portion 22d (lower end
portion in FIG. 6) of the second housing section 22.
[0137] In the classifying device 50, the flow path through which
the liquids 60, 60A, 60B, and 60C flow may be shut off from the
outside air. As discussed above, by shutting off the liquids 60,
60A, 60B, and 60C from the outside air, the cell aggregates 61a,
61b, 61c, and the isolated cells 62 contained in the liquids 60,
60A, 60B, and 60C can be prevented from being contaminated.
[0138] [Classifying Method]
[0139] A classifying method according to the first embodiment of
the present invention will be described with reference to FIG. 7.
FIG. 7 is a flowchart illustrating the classifying method according
to the first embodiment.
[0140] The classifying method according to the first embodiment
classifies the liquid 60 containing the cell aggregates 61a, 61b,
61c and the isolated cells 62, using the plurality of metallic
porous membranes 10A, 10B, and 10C, into the cell aggregates 61a,
61b, 61c and the isolated cells 62, respectively.
[0141] As shown in FIG. 7, the plurality of metallic porous
membranes 10A, 10B, and 10C are prepared in a step ST11.
Specifically, the metallic porous membranes 10A, 10B, and 10C are
arranged in that order from the upstream in the flow path through
which the liquid 60 flows (see FIG. 4). The metallic porous
membranes 10A, 10B, and 10C are not described herein because the
configurations thereof are the same as those in the above-described
classifying device 50.
[0142] The metallic porous membranes 10A, 10B, and 10C prepared in
the step ST11 may have experienced a sterilization process. The
sterilization process includes, for example, gamma-ray
sterilization by gamma-ray irradiation, autoclave sterilization by
saturated water vapor at high temperature and high pressure,
ethylene oxide gas sterilization using an ethylene oxide gas,
oxidation sterilization by ozone, or the like.
[0143] In a step ST12, by using the metallic porous membranes 10A,
10B, and 10C, the cell aggregates 61a, 61b, and 61c are
respectively classified. In the step ST12, the liquid 60 containing
the cell aggregates 61a, 61b, 61c and the isolated cells 62 is
filtered by passing through the metallic porous membranes 10A, 10B,
and 10C.
[0144] To be more specific, the liquid 60 is filtered by passing
through the metallic porous membrane 10A first. By the liquid 60
being filtered by the metallic porous membrane 10A, the cell
aggregates 61a larger than the dimension of the through-holes 12a
are captured on the first principal surface PS1 of the metallic
porous membrane 10A. Through this, the cell aggregates 61a are
classified.
[0145] Next, a filtrate obtained after being filtered by the
metallic porous membrane 10A, that is, the liquid 60A containing
the cell aggregates 61b, 61c and the isolated cells 62 is filtered
by passing through the metallic porous membrane 10B disposed on a
downstream side relative to the metallic porous membrane 10A. By
the liquid 60A being filtered by the metallic porous membrane 10B,
the cell aggregates 61b larger than the dimension of the
through-holes 12b are captured on the first principal surface PS1
of the metallic porous membrane 10B. Through this, the cell
aggregates 61b are classified.
[0146] Next, the filtrate obtained after being filtered by the
metallic porous membrane 10B, that is, the liquid 60B containing
the cell aggregates 61c and the isolated cells 62 is filtered by
passing through the metallic porous membrane 10C disposed on the
downstream side relative to the metallic porous membrane 10B. By
the liquid 60B being filtered by the metallic porous membrane 10C,
the cell aggregates 61c larger than the dimension of the
through-holes 12c are captured on the first principal surface PS1
of the metallic porous membrane 10C. Through this, the cell
aggregates 61c are classified.
[0147] Further, by the liquid 60B being filtered by the metallic
porous membrane 10C, the liquid 60C containing the isolated cells
62 can be obtained as the filtrate. The isolated cells 62 taken out
from the liquid 60C can be subcultured. In other words, the
isolated cells 62 contained in the liquid 60C can be moved to a new
culture medium and cultured again therein.
[0148] In a step ST13, the cell aggregates 61a, 61b, and 61c
captured by the metallic porous membranes 10A, 10B, and 10C,
respectively, are washed using a washing fluid. For example, by
flowing the washing fluid in the direction 70 in which the liquid
60 flows, the cell aggregates 61a, 61b, and 61c are washed in a
state of being captured by the metallic porous membranes 10A, 10B,
and 10C. The washing method for the cell aggregates 61a, 61b, and
61c is not limited thereto, and various kinds of washing methods
may be used. The step ST13 may be omitted.
[0149] In a step ST14, the cell aggregates 61a, 61b, and 61c
respectively captured by the metallic porous membranes 10A, 10B,
and 10C are collected. For example, the metallic porous membrane
10A in a state of capturing the cell aggregates 61a is detached,
set in a culture medium, and then vibrated in the thickness
direction of the metallic porous membrane 10A. Through this, the
cell aggregates 61a having been captured by the metallic porous
membrane 10A can be isolated from the first principal surface PS1
of the metallic porous membrane 10A and collected. Alternatively,
by passing a fluid for collection through the through-holes 12a in
a direction from the second principal surface PS2, to which the
cell aggregates 61a are not attached, toward the first principal
surface PS1, the cell aggregates 61a can be isolated from the first
principal surface PS1 of the metallic porous membrane 10A and
collected. The collecting method for the cell aggregates 61a, 61b,
and 61c is not limited thereto, and various kinds of collecting
methods may be used.
[0150] The cell aggregates 61a, 61b, and 61c collected in the
manner described above are used for medicine efficacy researches.
For example, in the case of researching medicine efficacy against
cancer, the cell aggregate 61c smaller in dimension than the cell
aggregates 61a and 61b is used in the medicine efficacy research
against early-stage cancer. In contrast, the medicine efficacy
research against advanced cancer is carried out using the cell
aggregate 61a.
[0151] [Effects]
[0152] With the metallic porous membrane 10 according to the first
embodiment, the following effects can be obtained.
[0153] The metallic porous membrane 10 is provided with the
membrane section 11 including the first principal surface PS1 for
capturing cell aggregates 61, the second principal surface PS2
opposing the first principal surface PS1, and the plurality of
through-holes 12 communicating with the first principal surface PS1
and the second principal surface PS2. With this configuration,
since the dimension accuracy when classifying the cell aggregates
61 can be enhanced, the collection rate of the cell aggregates 61
can be increased.
[0154] The metallic porous membrane 10 has a higher rigidity than a
filter made of a membrane, nylon mesh, or the like. Because of
this, in the metallic porous membrane 10, in the case of filtering
the liquid 60 containing the cell aggregates 61, the through-holes
12 are unlikely to be deformed compared to the filter made of a
membrane, nylon mesh, or the like even if the pressure due to the
liquid 60 is applied to the first principal surface PS1 of the
membrane section 11. Accordingly, the metallic porous membrane 10
can capture the cell aggregates 61 larger than the through-holes 12
on the first principal surface PS1 of the metallic porous membrane
10 with certainty in comparison with the filter made of a membrane,
nylon mesh, or the like. Because through-holes of the filter made
of a membrane, nylon mesh, or the like are likely to be deformed in
the case where the pressure due to the liquid 60 is applied to a
membrane surface thereof, there is a case in which the cell
aggregates 61 larger than the through-holes pass through the
filter.
[0155] In the metallic porous membrane 10, the through-hole 12
communicates through a wall surface continuously connecting an
opening on the first principal surface PS1 side of the membrane
section 11 and an opening on the second principal surface PS2 side
thereof. Further, the through-hole 12 is so provided that the
opening on the first principal surface PS1 side of the membrane
section 11 can be projected on the opening on the second principal
surface PS2 side thereof. With this configuration, the cell
aggregate 61 smaller than the through-hole 12 is likely to pass
through the through-hole 12. In a membrane filer, because the
though-hole does not communicate through a side wall continuously
connecting an opening on a first principal surface side of a
membrane section and an opening on a second principal surface side
thereof, the cell aggregate 61 smaller than the through-hole 12 is
unlikely to pass through the through-hole. Because of this, in the
membrane filter, the cell aggregates 61 are caused to remain in the
filter.
[0156] Further, in the metallic porous membrane 10, the first
principal surface PS1 of the membrane section 11 where the cell
aggregates 61 are captured is formed to be flat. That is, the first
principal surface PS1 of the membrane section 11 of the metallic
porous membrane 10 is formed flush. With this configuration, the
cell aggregate 61 smaller than the through-hole 12 of the metallic
porous membrane 10 is likely to be introduced into the through-hole
12. Further, when the cell aggregates 61 captured on the first
principal surface PS1 of the membrane section 11 of the metallic
porous membrane 10 are collected, the cell aggregates 61 can be
isolated with ease from the first principal surface PS1 of the
membrane section 11. In the filter made of a membrane, nylon mesh,
or the like, uneven portions are formed in the first principal
surface of the membrane section where the cell aggregates 61 are
captured. As such, because even the cell aggregate 61 smaller than
the through-hole is caught by the uneven portions in some case,
there is a case in which the cell aggregate 61 having a dimension
other than the desired dimension is collected. In addition, when
collecting the cell aggregates 61, the cell aggregates 61 may be
caught by the uneven portions.
[0157] The metallic porous membrane 10 is not changed even by flame
sterilization and has high thermal conductivity, thereby making it
possible to obtain a high sterilization effect.
[0158] As discussed above, the metallic porous membrane 10 is
configured such that the cell aggregates 61 larger than the
through-holes 12 can be more surely captured and the cell
aggregates 61 smaller than the through-holes 12 are likely to be
introduced into the through-holes 12. Further, with the metallic
porous membrane 10, the cell aggregates 61 can be isolated with
ease from the first principal surface PS1 of the membrane section
11 and collected. This makes it possible for the metallic porous
membrane 10 to increase the dimension accuracy of the cell
aggregates 61 to be classified and increase the collection rate in
comparison with the filter made of a membrane, nylon mesh, or the
like.
[0159] With the classifying device 50 according to the first
embodiment, the following effects can be obtained.
[0160] According to the classifying device 50, since the cell
aggregates 61 are classified using the above-described metallic
porous membrane 10, the collection rate of the cell aggregates 61
can be increased.
[0161] The classifying device 50 is provided with the metallic
porous membranes 10A, 10B, and 10C respectively including the
through-holes 12a, 12b, and 12c having mutually different
dimensions. The plurality of metallic porous membranes 10A, 10B,
and 10C are arranged in series from the upstream side of the flow
path, through which the liquid 60 containing the cell aggregates
61a, 61b, and 61c flows, in the descending order of the dimensions
of the through-holes 12a, 12b, and 12c. This configuration makes it
possible to classify the cell aggregates 61a, 61b, and 61c from the
liquid 60 using the plurality of metallic porous membranes 10A,
10B, and 10C, respectively. That is, according to the classifying
device 50, the cell aggregates 61a, 61b, and 61c having mutually
different dimensions can be obtained in the stepwise manner.
Further, with the classifying device 50, the cell aggregates 61a,
61b, and 61c which the metallic porous membrane on the upstream
side failed to capture can be collected by the metallic porous
membrane on the downstream side with certainty.
[0162] In the classifying device 50, the dimension of the
through-hole 12c of the metallic porous membrane 10C positioned at
the lowermost stage is so designed as to allow the isolated cell 62
to pass through. With this configuration, the liquid 60C containing
the isolated cells 62 can be obtained after having classified the
cell aggregates 61a, 61b, and 61c. This makes it possible for the
isolated cells 62 to be subcultured. In other words, by the
isolated cells 62 being moved to a new culture medium and cultured
again, life or death of the cells can be determined, for example.
Alternatively, the isolated cells 62 can also be used for producing
other cell aggregates.
[0163] In the classifying device 50, the metallic porous membranes
10A, 10B, and 10C can each be housed in the housing 20 that
includes the fluid introducing path 21a provided so as to oppose
the first principal surface PS1 of the metallic porous membrane and
the fluid discharging path 22a provided so as to oppose the second
principal surface PS2 of the metallic porous membrane. This
configuration makes it possible to hold each of the metallic porous
membranes 10A, 10B, and 10C with ease in the housing 20 including
the fluid introducing path 21a and the fluid discharging path 22a.
Because the first frame member 51 and the second frame member 52
pinching the outer circumference portion of each of the metallic
porous membranes 10A, 10B, and 10C are integrally formed with the
first housing section 21 and the second housing section 22,
respectively, the number of components of the classifying device 50
can be reduced.
[0164] With the classifying method according to the first
embodiment, the following effects can be obtained.
[0165] According to the classifying method, since the cell
aggregates 61 are classified using the above-described metallic
porous membrane 10, the collection rate of the cell aggregates 61
can be increased. Further, the stated classifying method has the
same effects as the above-discussed classifying device 50.
[0166] In the classifying method, the cell aggregates 61a, 61b, and
61c can be washed in a state of being captured by the metallic
porous membranes 10A, 10B, and 10C. For example, by flowing the
washing fluid in the direction 70 in which the liquid 60 flows, the
cell aggregates 61a, 61b, and 61c captured by the metallic porous
membranes 10A, 10B, and 10C can be washed. This makes it possible
to easily wash the classified cell aggregates 61a, 61b, and
61c.
[0167] In the classifying method, for example, by vibrating or the
like of the metallic porous membranes 10A, 10B, and 10C
respectively capturing the cell aggregates 61a, 61b, and 61c in the
thickness direction of the metallic porous membranes 10A, 10B, and
10C in a culture medium, the cell aggregates 61a, 61b, and 61c can
be collected with ease. Alternatively, by passing a fluid for
collection through the through-holes 12a in a direction from the
second principal surface PS2, to which the cell aggregates 61a are
not attached, toward the first principal surface PS1, the cell
aggregates 61a can be isolated from the first principal surface PS1
of the metallic porous membrane 10A and collected. In this manner,
the cell aggregates 61a, 61b, and 61c respectively captured by the
metallic porous membranes 10A, 10B, and 10C can be easily isolated
from the metallic porous membranes 10A, 10B, and 10C.
[0168] In the classifying method, medicine efficacy researches can
be carried out using the classified cell aggregates 61a, 61b, and
61c. Because the classified cell aggregates 61a, 61b, and 61c
respectively have uniform dimensions, variations in medicine
efficacy research data can be reduced.
[0169] Although the configuration of the classifying device 50
including the plurality of metallic porous membranes 10A, 10B, and
10C is described in the first embodiment, the embodiment is not
limited thereto. The classifying device 50 may include at least one
or more metallic porous membranes 10. Although the configuration in
which the plurality of metallic porous membranes 10A, 10B, and 10C
respectively include the through-holes 12a, 12b, and 12c having
mutually different dimensions has been described thus far, the
configuration is not limited thereto. For example, the plurality of
metallic porous membranes 10A, 10B, and 10C may include the
through-holes 12 having the same dimension. With the above
configuration, the cell aggregates 61a which the metallic porous
membrane 10A on the upstream side failed to capture can be captured
by the metallic porous membrane 10B on the downstream side.
[0170] Although the configuration in which the through-hole 12c of
the metallic porous membrane 10C positioned at the lowermost stage
is designed with a dimension that allows the isolated cell 62 to
pass through is described in the first embodiment, the embodiment
is not limited thereto. The through-hole 12c of the metallic porous
membrane 10C may be designed to have a size equal to or smaller
than that of the isolated cell 62 isolated from the cell
aggregates, for example. That is, the through-hole 12c of the
metallic porous membrane 10C may be designed with the same
dimension as that of the isolated cell 62, or designed with a
dimension smaller than that of the isolated cell 62.
[0171] Although the first housing section 21 and the second housing
section 22 are so configured as to be fitted to each other by the
plurality of projections 22c being inserted into the plurality of
through-holes 21c in the first embodiment, the present invention is
not limited thereto. For example, the configuration may be as
follows: that is, a plurality of through-holes are provided in the
first housing section 21 and a plurality of projections are
provided on the second housing section 22, and then the plurality
of projections are inserted into the plurality of through-holes,
whereby the first housing section 21 and the second housing section
22 are fitted to each other. It is sufficient that the first
housing section 21 and the second housing section 22 are so
configured as to be fitted to each other.
[0172] Although the configuration in which the first frame member
51 and the second frame member 52 are integrally formed with the
first housing section 21 and the second housing section 22,
respectively, is described in the first embodiment, the embodiment
is not limited thereto. For example, the first frame member 51 and
the second frame member 52 may be configured of different materials
from those of the first housing section 21 and the second housing
section 22.
[0173] Working examples will hereinafter be described.
[0174] (First Working Example)
[0175] In a first working example, the cell aggregates 61 were
classified using the metallic porous membrane 10 of the first
embodiment. As a first comparative example, the cell aggregates 61
were classified using a nylon mesh.
[0176] In the first working example and the first comparative
example, the liquid 60 containing the cell aggregates 61 is shown
in FIG. 8. As shown in FIG. 8, the liquid 60 contains the plurality
of cell aggregates 61 having different dimensions.
[0177] The cell aggregates 61 shown in FIG. 8 were produced in a
manner in which a cell suspension solution in a fluid volume of 0.2
ml containing NIH3T3/ras was disseminated in a dish with a diameter
being 35 mm and cultured for a day in a general incubator. In this
case, a culture medium was 3 ml in volume and a total number of
cell aggregates was approximately 1.times.10.sup.5.
[0178] In the first working example, the metallic porous membrane
10 of the first embodiment was used. The metallic porous membrane
10 is a circular mesh made of nickel. The outer diameter of the
metallic porous membrane 10 is 7.8 mm, and the membrane section 11
with a diameter of 6 mm is formed in a center portion of the
metallic porous membrane 10. In the membrane section 11, the
through-holes 12 formed in a square shape are provided in
tetragonal lattice arrangement. One side of the through-hole 12 is
120 .mu.m in length. An interval between the through-holes 12, that
is, a distance of a metal portion between two through-holes 12, 12
is 50 .mu.m. To rephrase, a lattice interval between the
through-holes 12 is 170 .mu.m. The thickness is 17 .mu.m. The
metallic porous membrane 10 has experienced a sterilization process
by gamma-irradiation before the classification is performed. In the
first working example, the liquid 60 containing the cell aggregates
61 having different dimensions as shown in FIG. 8 was made to pass
through the metallic porous membrane 10 to be filtered, whereby the
cell aggregates 61 were classified.
[0179] A nylon mesh was used in the first comparative example. The
nylon mesh is a circular mesh made of nylon 6.6. The outer diameter
of the nylon mesh is 7.8 mm, and a membrane section is formed in
the center portion. In the membrane section, square through-holes
are provided in tetragonal lattice arrangement. One side of the
through-hole is 131 .mu.m in length. An interval between the
through-holes, that is, a wire diameter of the nylon mesh is 72
.mu.m. To rephrase, a lattice interval between the through-holes is
203 .mu.m. The nylon mesh has not experienced the sterilization
process because the nylon mesh itself is damaged when being
irradiated with gamma rays. In the first comparative example, the
liquid 60 containing the cell aggregates 61 having different
dimensions as shown in FIG. 8 was made to pass through the nylon
mesh to be filtered, whereby the cell aggregates 61 were
classified.
[0180] FIG. 9 shows part of a photograph of the metallic porous
membrane 10 after having classified the cell aggregates 61 in the
first working example. FIG. 10 shows part of a photograph of the
nylon mesh after having classified the cell aggregates 61 in the
first comparative example.
[0181] It can be understood that the metallic porous membrane 10 of
the first working example shown in FIG. 9 has captured more cell
aggregates 61 in number than the nylon mesh of the first
comparative example shown in FIG. 10. That is, it can be understood
that more cell aggregates 61 in number have been collected in the
first working example than the first comparative example.
[0182] In a mesh structure of the first comparative example, when
pressure is applied to the membrane section by the liquid 60
passing through, the through-holes are deformed. As such, there is
a case in which the cell aggregate 61 larger in size than the
through-hole of the nylon mesh undesirably passes through the
deformed through-hole. Because of this, in the first comparative
example, it can be thought of that the cell aggregates 61 with a
dimension to be collected could not be collected by the nylon
mesh.
[0183] FIG. 11 shows an enlarged photograph of an intersecting
portion Z1 of the nylon mesh. Because the nylon mesh is produced by
interweaving linear nylon, a stepped portion is formed in a
thickness direction of the nylon mesh at the intersecting portion
Z1 where pieces of linear nylon intersect with each other. In other
words, a principal surface of the nylon mesh for capturing the cell
aggregates 61 becomes a surface undesirably including uneven
portions due to a plurality of stepped portions. Because of this,
there is a case in which the cell aggregate 61 capable of passing
through the through-hole of the nylon mesh is undesirably caught by
the intersecting portion Z1. The cell aggregate 61 caught by the
intersecting portion Z1 of the nylon mesh as described above cannot
be collected in some case. Even if the cell aggregate 61 caught by
the intersecting portion Z1 of the nylon mesh is collected, the
collected cell aggregate 61 does not have a desired dimension.
Accordingly, the cell aggregate 61 to be originally classified
cannot be obtained.
[0184] In contrast, in the metallic porous membrane 10 of the first
working example, the through-hole 12 is unlikely to be deformed
even if the pressure is applied to the membrane section 11 by the
liquid 60 passing through. Because of this, the cell aggregate 61
larger than the through-hole 12 of the metallic porous membrane 10
is unlikely to pass through the through-hole 12. Further, the first
principal surface PS1 of the metallic porous membrane 10 is formed
to be flat in the first working example. As such, in the first
working example, the cell aggregate 61 with a dimension capable of
passing through the through-hole 12 can pass through the
through-hole 12 without being caught in the first principal surface
PS1 of the metallic porous membrane 10. Accordingly, it can be
thought of that more cell aggregates 61 were able to be collected
in the first working example than the first comparative example.
Further, it can be thought of that the cell aggregates 61 with an
enhanced dimension accuracy can be collected in the first working
example compared to the first comparative example.
[0185] As discussed above, with the nylon mesh of the first
comparative example, a reduction in the collection rate of the cell
aggregates 61, an error in the classification, and a reduction in
reproductivity are generated. Accordingly, with the metallic porous
membrane 10 of the first working example, the collection rate of
the cell aggregates 61, the classification accuracy, and the
reproductivity can be enhanced in comparison with the nylon
mesh.
[0186] (Second Working Example)
[0187] In a second working example, the plurality of cell
aggregates 61a, 61b, and 61c having different dimensions were
classified using the classifying device 50 of the first embodiment.
As for the dimensions of the cell aggregates 61a, 61b, and 61c, the
dimension of the cell aggregate 61a is largest while the dimension
of the cell aggregate 61c is smallest.
[0188] In the second working example, the classifying device 50 of
the first embodiment was used. The metallic porous membranes 10A,
10B, and 10C of the classifying device 50 are circular meshes made
of nickel. The outer diameter of each of the metallic porous
membranes 10A, 10B, and 10C is 7.8 mm, and the membrane sections
11a, 11b, and 11c each having a diameter of 6 mm are formed in the
center portion. In the membrane sections 11a, 11b, and 11c, the
square through-holes 12a, 12b, and 12c are respectively provided in
the tetragonal lattice arrangement. The dimensions of the
through-holes 12a, 12b, and 12c are as follows: that is, one sides
of the respective squares are 180 .mu.m, 120 .mu.m, and 58 .mu.m;
lattice intervals are 260 .mu.m, 170 .mu.m, and 76.3 .mu.m; and
thicknesses are 20 .mu.m, 17 .mu.m, and 20 .mu.m. The metallic
porous membranes 10A, 10B, and 10C have experienced the
sterilization process by gamma-irradiation before the
classification is performed. In the classifying device 50 of the
second working example, the metallic porous membranes 10A, 10B, and
10C are arranged in that order from an upstream side of a flow path
of the liquid 60.
[0189] FIG. 12 shows the liquid 60 containing cell aggregates
having different dimensions in the second working example. In the
second working example, the liquid 60 of 1 ml containing the cell
aggregates having different dimensions as shown in FIG. 12 was
supplied into the classifying device 50 and filtered by a dead-end
system, so as to classify the cell aggregates 61a, 61b, and 61c.
The metallic porous membranes 10A, 10B, and 10C were taken out five
minutes later after the start of filtering. Next, 5-ml
physiological saline was made to pass through each of the metallic
porous membranes 10A, 10B, and 10C from a surface not capturing the
cell aggregates (second principal surface PS2) in a state in which
a surface capturing the cell aggregates (first principal surface
PS1) was made to face downward, whereby the cell aggregates were
collected in a petri dish. The collected cell aggregates were
observed under a microscope.
[0190] FIG. 13 shows an enlarged photograph of the cell aggregates
collected by the metallic porous membrane 10A in the second working
example. It can be understood that, as shown in FIG. 13, the cell
aggregates 61a larger than the through-holes 12a are captured in
the metallic porous membrane 10A.
[0191] FIG. 14 shows an enlarged photograph of the cell aggregates
collected by the metallic porous membrane 10B in the second working
example. It can be understood that, as shown in FIG. 14, the cell
aggregates 61b larger than the through-holes 12b are captured in
the metallic porous membrane 10B.
[0192] FIG. 15 shows an enlarged photograph of the cell aggregates
collected by the metallic porous membrane 10C in the second working
example. It can be understood that, as shown in FIG. 15, the cell
aggregates 61c larger than the through-holes 12c are captured in
the metallic porous membrane 10C.
[0193] In addition, the liquid 60 was filtered to be classified
under the same conditions as those of the second working example
described above, and then part of each of the liquids 60A, 60B, and
60C after having been filtered by the metallic porous membranes
10A, 10B, and 10C was observed under a microscope in an enlarged
manner.
[0194] FIG. 16 shows a photograph in which part of the liquid 60A
after having passed through the metallic porous membrane 10A is
enlarged in the second working example. As shown in FIG. 16, it can
be understood that the cell aggregates 61b, 61c and the isolated
cell 62 are contained in the liquid 60A having passed through the
metallic porous membrane 10A but the cell aggregate 61a is not
contained therein.
[0195] FIG. 17 shows a photograph in which part of the liquid 60B
after having passed through the metallic porous membrane 10B is
enlarged in the second working example. As shown in FIG. 17, it can
be understood that the cell aggregate 61c and the isolated cell 62
are contained in the liquid 60B having passed through the metallic
porous membrane 10B but the cell aggregate 61b is not contained
therein.
[0196] FIG. 18 shows a photograph in which part of the liquid 60C
after having passed through the metallic porous membrane 10C is
enlarged in the second working example. As shown in FIG. 18, it can
be understood that the isolated cell 62 is contained in the liquid
60C having passed through the metallic porous membrane 10C but the
cell aggregate 61c is not contained therein.
[0197] As discussed thus far, the classifying device 50 of the
second working example can capture the cell aggregates 61a, 61b,
and 61c of the desired dimensions in the metallic porous membranes
10A, 10B, and 10C, respectively. In other words, the classifying
device 50 of the second working example can classify the cell
aggregates 61a, 61b, and 61c having mutually different dimensions
in the stepwise manner.
[0198] (Third Working Example)
[0199] In a third working example, cultured cell aggregates
(spheroids) were classified in accordance with sizes of the cell
aggregates using the classifying device 50 of the first
embodiment.
[0200] The cell aggregates were cultured such that NIH3T3 cells in
which ras genes had been introduced were cultured in a DMEM culture
medium of 1% PCSM containing 10% FBS. A container used was a 3.5-mm
dish, and the number of disseminated cells was 3.times.10.sup.5/ml.
The cells were cultured in an incubation at 37.degree. C. for 24
hours, and as a result, cell aggregates of various sizes were able
to be produced.
[0201] FIG. 19 shows a photograph in which part of the cultured
cell aggregates is enlarged. As shown in FIG. 19, it can be
understood that the cell aggregates 61a, 61b, and 61c having
mutually different sizes are produced before the
classification.
[0202] In the third working example, the hole sizes of the
through-holes 12a, 12b, and 12c of the metallic porous membranes
10A, 10B, and 10C in the classifying device 50 are 180 .mu.m, 100
.mu.m, and 58 .mu.m, respectively. Here, the through-holes 12a,
12b, and 12c are each formed in a square shape, and the hole size
refers to the length d of one side of the hole of the square
shape.
[0203] In the third working example, the culture medium 60
containing the cell aggregates 61a, 61b, and 61c having mutually
different sizes as shown in FIG. 19 was made to pass through the
metallic porous membranes 10A, 10B, and 10C in that order, whereby
the cell aggregates 61a, 61b, and 61c were classified.
Specifically, three 3.5-mm dishes, in each of which a culture fluid
was newly supplied, were prepared, and the cell aggregates 61a,
61b, and 61c captured by the metallic porous membranes 10A, 10B,
and 10C were moved to the corresponding 3.5-mm dishes by being
backwashed.
[0204] FIG. 20 shows a photograph in which part of the cell
aggregate 61a captured by the metallic porous membrane 10A is
enlarged in the third working example. FIG. 21 shows a photograph
in which part of the cell aggregate 61b captured by the metallic
porous membrane 10B is enlarged in the third working example. FIG.
22 shows a photograph in which part of the cell aggregate 61c
captured by the metallic porous membrane 10C is enlarged in the
third working example. FIG. 23 shows a photograph in which part of
the liquid 60 after having passed through the metallic porous
membrane 10C is enlarged in the third working example.
[0205] It can be understood that, as shown in FIGS. 20 to 22, the
cell aggregates 61a, 61b, and 61c respectively having substantially
equal sizes are captured in the metallic porous membranes 10A, 10B,
and 10C. Further, as shown in FIG. 23, it can be understood that
the cell aggregates 61a, 61b, and 61c are not contained in the
liquid 60 having passed through the metallic porous membrane 10C
but a cell aggregate 61d smaller in size than the cell aggregates
61a, 61b, and 61c is contained therein. The liquid 60 after having
passed the metallic porous membrane 10C may contain, for example,
the isolated cell 62 or the like in addition to the cell aggregate
61d.
[0206] In the third working example, as discussed above, the
following can be understood: that is, the culture medium 60
containing the cell aggregates 61a, 61b, and 61c having mutually
different sizes (see FIG. 19) was made to pass through the metallic
porous membranes 10A, 10B, and 10C, whereby the cell aggregates
61a, 61b, and 61c were able to be classified in accordance with
their sizes (see FIGS. 20 to 23).
[0207] Next, in order to examine a relationship between size and
activity of cell aggregates, the culture medium containing the cell
aggregates was equally divided for each dish, and ATP active mass
was measured with respect to one culture medium of the equally
divided medium. In this case, the ATP active mass was measured
using an ATP quantifying assay (CellTiter-Glo (registered
trademark), Promega). The ATP active mass refers to activity of a
cell, that is, the probability of survival of a cell. In other
words, it means that, as the value of the ATP active mass is
larger, the number of living cells is larger. The other culture
medium of the equally divided medium was used for re-culture which
will be explained later.
[0208] The cell aggregates in the dishes were selected one by one
at random with a pipette and supplied into a U-bottom plate
(375-well). Then, the diameter and the ATP active mass of each cell
aggregate were measured using Cell Imager. Selected were 17 cell
aggregates 61a from among the cell aggregates 61a captured by the
metallic porous membrane 10A with the hole size being 180 .mu.m, 20
cell aggregates 61b from among the cell aggregates 61b captured by
the metallic porous membrane 10B with the hole size being 100
.mu.m, and 12 cell aggregates 61c from among the cell aggregates
61c captured by the metallic porous membrane 10C with the hole size
being 58 .mu.m.
[0209] FIG. 24 is a graph showing a measurement result of the ATP
active mass with respect to the diameter of a cell aggregate in the
third working example. The horizontal axis in FIG. 24 represents
the diameter of a cell aggregate, and the vertical axis represents
the ATP active mass. In FIG. 24, square points show the data
related to the cell aggregates 61a captured by the metallic porous
membrane 10A with the hole size being 180 .mu.m, triangular points
show the data related to the cell aggregates 61b captured by the
metallic porous membrane 10B with the hole size being 100 .mu.m,
and rhombic points show the data related to the cell aggregates 61c
captured by the metallic porous membrane 10C with the hole size
being 58 .mu.m.
[0210] It can be understood that, as shown in FIG. 24, the activity
of the cells captured by the respective metallic porous membranes
10A, 10B, and 10C is maintained. To be specific, the ATP active
mass is such that the value of the active mass (RLU light emission
amount) is larger as the number of living cells is larger. The cell
aggregate is configured to include a larger number of cells as the
size of the cell aggregate becomes larger. Because of this, as the
size of the cell aggregate is larger, the value of the ATP active
mass becomes larger if the cells included in the cell aggregate are
alive.
[0211] As shown in FIG. 24, it can be understood that the value of
the ATP active mass becomes larger as the diameter of the cell
aggregate becomes larger. From this, it can be understood that the
activity of the cells captured by the respective metallic porous
membranes 10A, 10B, and 10C is maintained. That is, it can be
understood that the cells captured by the respective metallic
porous membranes 10A, 10B, and 10C are alive. Originally, only the
cells near a surface of the cell aggregate are maintained to be
active while the cells at the center of the cell aggregate have
lost their activity. Because of this, the relationship between the
diameter and the ATP active mass of the cell aggregate exhibits a
quadratic or cubic curve.
[0212] As for the cell aggregates captured by the respective
metallic porous membranes 10A, 10B, and 10C, maximum values,
minimum values, average values, and standard deviations of the
diameters of the cell aggregates are shown in Table 1.
TABLE-US-00001 TABLE 1 Fraction of Hole Fraction of Hole Fraction
of Hole Diameter of Cell Size 180 .mu.m Size 100 .mu.m Size 58
.mu.m Aggregate (n = 17) (n = 20) (n = 12) Maximum Value 495 268
158 (.mu.m) Minimum Value 267 138 65 (.mu.m) Average Value 365 203
111 (.mu.m) Standard 68 36 30 Deviation
[0213] As shown in Table 1, the maximum values of the diameters of
the cell aggregates captured by the metallic porous membrane 10A
with the hole size being 180 .mu.m, the metallic porous membrane
10B with the hole size being 100 .mu.m, and the metallic porous
membrane 10C with the hole size being 58 .mu.m were respectively
495 .mu.m, 268 .mu.m, and 158 .mu.m. The minimum values of the
diameters of the captured cell aggregates were 267 .mu.m, 138
.mu.m, and 65 .mu.m in the order of the metallic porous membranes
10A, 10B, and 10C. The average values of the diameters of the
captured cell aggregates were 365 .mu.m, 203 .mu.m, and 111 .mu.m
in the order of the metallic porous membranes 10A, 10B, and 10C.
The standard deviations of the captured cell aggregates were 68,
36, and 30 in the order of the metallic porous membranes 10A, 10B,
and 10C. Ratios of the standard deviations to the corresponding
average values of the captured cell aggregates were 19%, 18%, and
27% in the order of the metallic porous membranes 10A, 10B, and
10C.
[0214] Further, the cell aggregates 61a, 61b, and 61c having been
classified were re-cultured. The other culture medium of the
equally divided medium described above was used for the
re-culture.
[0215] Of the cell aggregates 61a, 61b, and 61c in the dishes,
three cell aggregates each were selected at random as one group
with a pipette, and the one group was supplied into a U-bottom
plate (375-well). FIG. 25 shows a photograph of a group of the cell
aggregates 61a captured by the metallic porous membrane 10A with
the hole size being 180 .mu.m in the third working example. FIG. 26
shows a photograph of a group of the cell aggregates 61b captured
by the metallic porous membrane 10B with the hole size being 100
.mu.m in the third working example. FIG. 27 shows a photograph of a
group of the cell aggregates 61c captured by the metallic porous
membrane 10C with the hole size being 58 .mu.m in the third working
example.
[0216] In the third working example, produced were 33 groups of the
cell aggregates 61a, as shown in FIG. 25, captured by the metallic
porous membrane 10A, 43 groups of the cell aggregates 61b, as shown
in FIG. 26, captured by the metallic porous membrane 10B with the
hole size being 100 .mu.m, and 34 groups of the cell aggregates
61c, as shown in FIG. 27, captured by the metallic porous membrane
10C with the hole size being 58 .mu.m. These were cultured in the
incubation at 37.degree. C. for 24 hours, and as a result, one cell
aggregate was able to be produced from three cell aggregates.
[0217] FIG. 28 shows a photograph of one cell aggregate 63 produced
by culturing three cell aggregates 61a, as shown in FIG. 25, having
been captured by the metallic porous membrane 10A in the third
working example. FIG. 29 shows a photograph of one cell aggregate
64 produced by culturing three cell aggregates 61b, as shown in
FIG. 26, having been captured by the metallic porous membrane 10B.
FIG. 30 shows a photograph of one cell aggregate 65 produced by
culturing three cell aggregates 61c, as shown in FIG. 27, having
been captured by the metallic porous membrane 10C.
[0218] Sizes of the cell aggregates 63, 64, and 65 shown in FIGS.
28 to 30, having been produced by re-culturing, were measured using
the above-mentioned Cell Imager. Average values and standard
deviations of the sizes of the cell aggregates 63, 64, and 65 were
respectively 340.+-.81 .mu.m, 194.+-.34 .mu.m, and 110.+-.30 .mu.m.
Ratios of the standard deviations to the corresponding average
values of the sizes of the cell aggregates 63, 64, and 65 were
respectively 24%, 18%, and 27%. These values were equivalent to
those in Table 1, which shows the result of the classification
using the metallic porous membranes 10A, 10B, and 10C.
[0219] The above results indicate that, in the production of cell
aggregates, cell aggregates of desired sizes can be classified from
a culture medium, which contains cell aggregates having different
sizes, by using the metallic porous membranes 10A, 10B, and 10C.
The above results also indicate that, in the case where culturing
is further performed on the cell aggregates classified using the
metallic porous membranes 10A, 10B, and 10C, sizes of the cultured
cell aggregates are likely to be uniformed.
[0220] (Fourth Working Example)
[0221] In a fourth working example, medicine efficacy research was
carried out using the cell aggregates (spheroids) classified using
the classifying device 50 of the first embodiment. In addition, as
a second comparative example, medicine efficacy research was
carried out using the cell aggregates that had not experienced the
classification, that is, using the cell aggregates having different
sizes.
[0222] In the fourth working example and the second comparative
example, medicine efficacy of an anticancer drug Bortezomib was
researched. Bortezomib is a proteasome inhibitor used to treat
recurrence or intractable multiple myeloma. It is well-known that,
as a mechanism of action, Bortezomib brings antitumor action by
apoptosis induction, inhibition of proliferation, and inhibition of
angiogenesis. It is also well-known that Bortezomib inhibits
activation of NF-kB, and brings adhesion inhibition and/or
inhibition of IL-6 secretion.
[0223] The cell aggregates were cultured such that NIH3T3/EGFP
cells in which ras genes had been introduced were cultured in a
DMEM culture medium of 1% PCSM containing 10% FBS. A container used
was a 3.5-mm dish, and the number of disseminated cells was
1.times.10.sup.5/ml. The cells were cultured in the incubation at
37.degree. C. for 24 hours, and as a result, cell aggregates of
various sizes were able to be produced. The culture medium
containing the above cell aggregates was equally divided into two
portions, and one of them was used in the fourth working example
while the other of them was used in the second comparative
example.
[0224] In the fourth working example, after having passed through
the metallic porous membrane 10A with the hole size being 180 .mu.m
and the metallic porous membrane 10B with the hole size being 100
.mu.m, the cell aggregates captured on the metallic porous membrane
10B were selected one by one and supplied into a U-bottom plate
(375-well). Then, the diameter and volume of each cell aggregate
were measured with the Cell Imager.
[0225] In the fourth working example, Bortezomib was inputted into
the wells in the amounts of 1, 3, 10, 20, and 100 nM, respectively.
Then, after culturing for 24 hours in the incubation at 37.degree.
C., the ATP active mass was measured using the ATP quantifying
assay (CellTiter-Glo (registered trademark), Promega). Then, after
further culturing for 24 hours (48 hours in total) in the
incubation at 37.degree. C., the ATP active mass was measured.
[0226] FIG. 31 shows a measurement result of the ATP active mass of
the cell aggregates having been cultured for 24 hours after the
input of Bortezomib in the amounts of 1, 3, 10, 20, and 100 nM,
respectively, in the fourth working example. FIG. 32 shows a
measurement result of the ATP active mass of the cell aggregates
having been cultured for 48 hours after the input of Bortezomib in
the amounts of 1, 3, 10, 20, and 100 nM, respectively, in the
fourth working example. In each of FIGS. 31 and 32, the vertical
axis represents an ATP activity ratio, and the horizontal axis
represents Bortezomib concentration.
[0227] In contrast, in the second comparative example, without
performing classification using the metallic porous membrane, the
cell aggregates were selected one by one and supplied into a
U-bottom plate (375-well). Then, the diameter and the volume of
each cell aggregate were measured with the Cell Imager.
[0228] In the second comparative example, Bortezomib was inputted
into the wells in the amounts of 1, 3, 10, 20, and 100 nM,
respectively. Then, after culturing for 24 hours in the incubation
at 37.degree. C., the ATP active mass was measured using the ATP
quantifying assay (CellTiter-Glo (registered trademark), Promega).
Then, after further culturing for 24 hours (48 hours in total) in
the incubation at 37.degree. C., the ATP active mass was
measured.
[0229] FIG. 33 shows a measurement result of the ATP active mass of
the cell aggregates having been cultured for 24 hours after the
input of Bortezomib in the amounts of 1, 3, 10, 20, and 100 nM,
respectively, in the second comparative example. FIG. 34 shows a
measurement result of the ATP active mass of the cell aggregates
having been cultured for 48 hours after the input of Bortezomib in
the amounts of 1, 3, 10, 20, and 100 nM, respectively, in the
second comparative example. In each of FIGS. 33 and 34, the
vertical axis represents the ATP activity ratio, and the horizontal
axis represents the Bortezomib concentration.
[0230] When the ATP activity ratios of the fourth working example
shown in FIGS. 31 and 32 and the ATP activity ratios of the second
comparative example shown in FIGS. 33 and 34 are compared with each
other, it can be understood that error bars of the fourth working
example are smaller than those of the second comparative example.
This indicates that, in a medicine efficacy examination (medicine
efficacy research or medicine efficacy development) using cell
aggregates, a highly reliable result can be obtained by performing
the medicine efficacy examination using the cell aggregates of
uniform size obtained by classification using the metallic porous
membrane 10. In other words, classifying the cell aggregates using
the metallic porous membrane 10 brings an effect that a medicine
efficacy examination result can be obtained with high accuracy.
Because the metallic porous membrane 10 has a higher mechanical
strength than a nylon mesh or the like, its classification accuracy
is higher. Accordingly, with the metallic porous membrane 10, in a
medicine efficacy examination, an error in the examination result
due to the size of the cell aggregates can be made small in
comparison with the nylon mesh or the like.
Fifth Working Example
[0231] In the fifth working example, in order to research influence
of the metallic porous membrane 10 on the culture of cell
aggregates, cell aggregates were cultured in a state in which the
metallic porous membrane 10 having experienced flame sterilization
was soaked in a culture fluid. In addition, as a third comparative
example, cell aggregates were cultured in a state in which the
metallic porous membrane 10 was not soaked in a culture fluid.
[0232] In the fifth working example and the third comparative
example, NIH3T3 cells in which ras genes had been introduced were
cultured in a culture medium where 5% FCS and 1% PCSM were added to
a Dulbecco's Modified Eagle Medium DMEM (manufacture by Nacalai
tesque).
[0233] FIG. 35 illustrates a culturing state of cells 66 in the
fifth working example and the third comparative example. As shown
in FIG. 35, a well plate 80 (Sumilon tight plate 24F manufactured
by Sumitomo Bakelite) was prepared. In the well plate 80, the cells
66 and the culture medium 60 of the third comparative example were
disseminated in three wells of an A row, while the cells 66 and the
culture medium 60 of the fifth working example were disseminated in
three wells of a C row. The amount of dissemination per well was
such that the number of cells was 7.0.times.10.sup.4, and the
culture medium was 2 ml.
[0234] In the fifth working example, three metallic porous
membranes 10 were prepared and exposed to a burner for one second.
Thereafter, the metallic porous membranes 10 were cut and soaked in
the culture media 60 in the wells. The outer diameter and the
thickness of the metallic porous membrane 10 used in the fifth
working example were 18 mm and 40 .mu.m, respectively. The
through-hole 12 was formed in a square shape, and the length of one
side of the stated square shape was 58 .mu.m. The distance b
between two through-holes 12 was 18 .mu.m.
[0235] In the fifth working example, the cells 66 were cultured for
10 minutes in a state in which the metallic porous membranes 10
were soaked in the culture media 60, and thereafter the metallic
porous membranes 10 were removed. In contrast, in the third
comparative example, the cells 66 were cultured for 10 minutes
without the metallic porous membranes 10 being soaked in the
culture media. Then, the active mass of the cells cultured in each
of the fifth working example and the third comparative example was
confirmed by a method as follows.
[0236] The culture media 60 and the cells 66 of the fifth working
example as well as the culture media 60 and the cells 66 of the
third comparative example were respectively divided into 20
portions so as to be dispensed to separate plates. An ATP reagent,
manufactured by TOYOINK, was added in the amount of 100 .mu.l to
each of the dispensed portions of the culture media and the cells,
and thereafter the RLU light emission amount (ATP active mass) was
measured with a plate reader (Fusion a-FP manufactured by Perkin
Elmer).
[0237] FIG. 36 shows a measurement result of the RLU light emission
amount (ATP active mass) of the cultured cells in each of the fifth
working example and the third comparative example. As shown in FIG.
36, it can be understood that the RLU light emission amount (ATP
active mass) of the fifth working example is equivalent to that of
the third comparative example when compared with each other. This
indicates that the metallic porous membranes 10 having experienced
the flame sterilization do not have any influence on the culture of
the cells.
Sixth Working Example
[0238] In a sixth working example, cell aggregates (spheres or
embryoid bodies) derived from cultured mouse ES cells were
classified in accordance with their sizes using the classifying
device 50 of the first embodiment. The metallic porous membrane 10
is a circular mesh made of nickel. The outer diameter of the
metallic porous membrane 10 is 7.8 mm, and the membrane section 11
with a diameter of 6 mm is formed in the center portion of the
metallic porous membrane 10. In the membrane section 11, the
through-holes 12 formed in a square shape are provided in
tetragonal lattice arrangement. One side of the through-hole 12 is
120 .mu.m in length. An interval between the through-holes 12, that
is, a distance of a metal portion between two through-holes 12 is
50 .mu.m. To rephrase, a lattice interval between the through-holes
12 is 170 .mu.m. The thickness is 17 .mu.m. The metallic porous
membrane 10 has experienced the sterilization process by
gamma-irradiation before the classification is performed. In the
sixth working example, the liquid 60 containing the cell aggregates
61 having different dimensions as shown in FIG. 37 was made to pass
through the metallic porous membrane 10 to be filtered, whereby the
cell aggregates 61 were classified.
[0239] The cell aggregates were cultured such that mouse ES cells
were cultured in a DMEM culture medium of 1% PCSM containing 10%
FBS. A container used was a 3.5-mm dish, and the number of
disseminated cells was 3.times.10.sup.5/ml. The cells were cultured
in the incubation at 37.degree. C. for 48 hours, and as a result,
cell aggregates of various sizes were able to be produced.
[0240] FIG. 37 shows a photograph in which part of the cultured
cell aggregates is enlarged. As shown in FIG. 37, it can be
understood that the cell aggregates 61a, 61b, and 61c having
mutually different sizes are produced before the
classification.
[0241] In the sixth working example, the hole sizes of the
through-holes 12a, 12b, and 12c of the metallic porous membranes
10A, 10B, and 10C in the classifying device 50 are 180 .mu.m, 100
.mu.m, and 58 .mu.m, respectively. Here, the through-holes 12a,
12b, and 12c are each formed in a square shape, and the hole size
refers to the length d of one side of the hole of the square
shape.
[0242] In the sixth working example, the culture medium 60
containing the cell aggregates 61a, 61b, and 61c having mutually
different sizes as shown in FIG. 37 was made to pass through the
metallic porous membranes 10A, 10B, and 10C in that order, whereby
the cell aggregates 61a, 61b, and 61c were classified.
Specifically, three 3.5-mm dishes, in each of which a culture fluid
was newly supplied, were prepared, and the cell aggregates 61a,
61b, and 61c captured by the metallic porous membranes 10A, 10B,
and 10C were moved to the corresponding 3.5-mm dishes by being
backwashed.
[0243] FIG. 38 shows a photograph in which part of the cell
aggregate 61a captured by the metallic porous membrane 10A is
enlarged in the sixth working example. FIG. 39 shows a photograph
in which part of the cell aggregate 61b captured by the metallic
porous membrane 10B is enlarged in the sixth working example. FIG.
40 shows a photograph in which part of the cell aggregate 61c
captured by the metallic porous membrane 10C is enlarged in the
sixth working example. FIG. 41 shows a photograph in which part of
the liquid 60 after having passed through the metallic porous
membrane 10C is enlarged in the sixth working example.
[0244] It can be understood that, as shown in FIGS. 38 to 41, the
cell aggregates 61a, 61b, and 61c respectively having substantially
equal sizes are captured in the metallic porous membranes 10A, 10B,
and 10C. Further, as shown in FIG. 41, it can be understood that
the cell aggregates 61a, 61b, and 61c are not contained in the
liquid 60 after having passed through the metallic porous membrane
10C but the cell aggregate 61d smaller in size than the cell
aggregates 61a, 61b, and 61c is contained therein. The liquid 60
after having passed the metallic porous membrane 10C may contain,
for example, the isolated cell 62 or the like in addition to the
cell aggregate 61d.
[0245] In the sixth working example, as discussed above, the
following can be understood: that is, the culture medium 60
containing the cell aggregates 61a, 61b, and 61c having mutually
different sizes (see FIG. 37) was made to pass through the metallic
porous membranes 10A, 10B, and 10C, whereby the cell aggregates
61a, 61b, and 61c were able to be classified in accordance with
their sizes (see FIGS. 38 to 41).
[0246] Next, in order to examine a relationship between size and
activity of cell aggregates, a culture medium containing cell
aggregates were equally divided for each dish, and the ATP active
mass was measured with respect to one culture medium of the equally
divided medium. In this case, the ATP active mass was measured
using an ATP quantifying assay (CellTiter-Glo (registered
trademark), Promega). The ATP active mass refers to activity of a
cell, that is, the probability of survival of a cell. In other
words, it means that, as the value of the ATP active mass is
larger, the number of living cells is larger. The other culture
medium of the equally divided medium was used for re-culture which
will be explained later.
[0247] The cell aggregates in the dishes were selected one by one
at random with a pipette and supplied into a U-bottom plate
(375-well). Then, the diameter and the ATP active mass of each cell
aggregate were measured with the Cell Imager. Selected were 13 cell
aggregates 61a from among the cell aggregates 61a captured by the
metallic porous membrane 10A with the hole size being 180 .mu.m, 10
cell aggregates 61b from among the cell aggregates 61b captured by
the metallic porous membrane 10B with the hole size being 100
.mu.m, and 16 cell aggregates 61c from among the cell aggregates
61c captured by the metallic porous membrane 10C with the hole size
being 58 .mu.m.
[0248] FIG. 42 shows a measurement result of the ATP active mass
with respect to the diameter of a cell aggregate in the sixth
working example. The horizontal axis in FIG. 42 represents the
diameter of a cell aggregate, and the vertical axis represents the
ATP active mass. In FIG. 42, square points show the data related to
the cell aggregates 61a captured by the metallic porous membrane
10A with the hole size being 180 .mu.m, triangular points show the
data related to the cell aggregates 61b captured by the metallic
porous membrane 10B with the hole size being 100 .mu.m, and rhombic
points show the data related to the cell aggregates 61c captured by
the metallic porous membrane 10C with the hole size being 58
.mu.m.
[0249] It can be understood that, as shown in FIG. 42, the activity
of the cells captured by the respective metallic porous membranes
10A, 10B, and 10C is maintained. To be specific, the value of the
ATP active mass (RLU light emission amount) is larger as the number
of living cells is larger. The cell aggregate is configured to
include a larger number of cells as the size of the cell aggregate
becomes larger. Because of this, as the size of the cell aggregate
is larger, the value of the ATP active mass becomes larger if the
cells included in the cell aggregate are alive.
[0250] As shown in FIG. 42, it can be understood that the value of
the ATP active mass becomes larger as the diameter of the cell
aggregate becomes larger. From this, it can be understood that the
activity of the cells captured by the respective metallic porous
membranes 10A, 10B, and 10C is maintained. That is, it can be
understood that the cells captured by the respective metallic
porous membranes 10A, 10B, and 10C are alive. Originally, only the
cells near a surface of the cell aggregate are maintained to be
active while the cells at the center of the cell aggregate have
lost their activity. Because of this, the relationship between the
diameter and the ATP active mass of the cell aggregate exhibits a
quadratic or cubic curve.
[0251] As for the cell aggregates captured by the respective
metallic porous membranes 10A, 10B, and 10C, maximum values,
minimum values, average values, and standard deviations of the
diameters of the cell aggregates are shown in Table 2.
TABLE-US-00002 TABLE 2 Fraction of Hole Fraction of Hole Fraction
of Hole Diameter of Cell Size 180 .mu.m Size 100 .mu.m Size 58
.mu.m Aggregate (n = 13) (n = 10) (n = 16) Maximum Value 649 211
136 (.mu.m) Minimum Value 276 142 59 (.mu.m) Average Value 413 178
99 (.mu.m) Standard 130 22 25 Deviation
[0252] As shown in Table 2, the maximum values of the diameters of
the cell aggregates captured by the metallic porous membrane 10A
with the hole size being 180 .mu.m, the metallic porous membrane
10B with the hole size being 100 .mu.m, and the metallic porous
membrane 10C with the hole size being 58 .mu.m were respectively
649 .mu.m, 211 .mu.m, and 136 .mu.m. The minimum values of the
diameters of the captured cell aggregates were 276 .mu.m, 142
.mu.m, and 59 .mu.m in the order of the metallic porous membranes
10A, 10B, and 10C. The average values of the diameters of the
captured cell aggregates were 413 .mu.m, 178 .mu.m, and 99 .mu.m in
the order of the metallic porous membranes 10A, 10B, and 10C. The
standard deviations of the captured cell aggregates were 68, 36,
and 30 in the order of the metallic porous membranes 10A, 10B, and
10C. Ratios of the standard deviations to the corresponding average
values of the captured cell aggregates were 31%, 12%, and 23% in
the order of the metallic porous membranes 10A, 10B, and 10C.
[0253] Further, the cell aggregates 61a, 61b, and 61c having been
classified were re-cultured. The other culture medium of the
equally divided medium discussed above was used for the
re-culture.
[0254] Of the cell aggregates 61a, 61b, and 61c in the dishes,
three cell aggregates each were selected at random as one group
with a pipette, and the one group was supplied into a U-bottom
plate (375-well). FIG. 43 shows a photograph of a group of the cell
aggregates 61a captured by the metallic porous membrane 10A with
the hole size being 180 .mu.m in the sixth working example. FIG. 44
shows a photograph of a group of the cell aggregates 61b captured
by the metallic porous membrane 10B with the hole size being 100
.mu.m in the sixth working example. FIG. 45 shows a photograph of a
group of the cell aggregates 61c captured by the metallic porous
membrane 10C with the hole size being 58 .mu.m in the sixth working
example.
[0255] In the sixth working example, produced were 30 groups of the
cell aggregates 61a, as shown in FIG. 43, captured by the metallic
porous membrane 10A, 17 groups of the cell aggregates 61b, as shown
in FIG. 44, captured by the metallic porous membrane 10B with the
hole size being 100 .mu.m, and 50 groups of the cell aggregates
61c, as shown in FIG. 45, captured by the metallic porous membrane
10C with the hole size being 58 .mu.m. These were cultured in the
incubation at 37.degree. C. for 24 hours, and as a result, one cell
aggregate was able to be produced from three cell aggregates.
[0256] FIG. 46 shows a photograph of one cell aggregate 63 produced
by culturing three cell aggregates 61a, as shown in FIG. 43, having
been captured by the metallic porous membrane 10A in the sixth
working example. FIG. 47 shows a photograph of one cell aggregate
64 produced by culturing three cell aggregates 61b, as shown in
FIG. 44, having been captured by the metallic porous membrane 10B.
FIG. 48 shows a photograph of one cell aggregate 65 produced by
culturing three cell aggregates 61c, as shown in FIG. 45, having
been captured by the metallic porous membrane 10C.
[0257] Sizes of the cell aggregates 63, 64, and 65 as shown in
FIGS. 46 to 48, having been produced by re-culturing, were measured
using the above-mentioned Cell Imager. Average values and standard
deviations of the sizes of the cell aggregates 63, 64, and 65 were
respectively 441.+-.146 .mu.m, 203.+-.26 .mu.m, and 114.+-.34
.mu.m. Ratios of the standard deviations to the corresponding
average values of the sizes of the cell aggregates 63, 64, and 65
were respectively 33%, 13%, and 30%. These values were equivalent
to those in Table 2, which shows the result of the classification
using the metallic porous membranes 10A, 10B, and 10C.
[0258] The above results indicate that, in the production of cell
aggregates, cell aggregates of desired sizes can be classified from
a culture medium containing cell aggregates of different sizes by
using the metallic porous membranes 10A, 10B, and 10C. The above
results also indicate that, in the case where culturing is further
performed on the cell aggregates classified using the metallic
porous membranes 10A, 10B, and 10C, sizes of the cultured cell
aggregates are likely to be uniformed.
[0259] The present invention is sufficiently described being
related to preferred embodiments with reference to the accompanying
drawings, and it is apparent to those skilled in the art that
various variations and modifications can be carried out. Such
variations and modifications should be taken to be included in the
scope of the present invention without departing from the scope of
the present invention as set out in the appended claims.
[0260] Because the present invention can classify cell aggregates
while enhancing the collection rate of the cell aggregates, the
invention is useful, for example, in the fields of medicine
efficacy research, regenerative medical drug production, and so
on.
REFERENCE SIGNS LIST
[0261] 10, 10A, 10B, 10C METALLIC POROUS MEMBRANE [0262] 11, 11a,
11b, 11c MEMBRANE SECTION [0263] 12, 12a, 12b, 12c THROUGH-HOLE
[0264] 20 HOUSING [0265] 21 FIRST HOUSING SECTION [0266] 21a FLUID
INTRODUCING PATH [0267] 21b FLANGE SECTION [0268] 21c THROUGH-HOLE
[0269] 21d TERMINAL END PORTION [0270] 22 SECOND HOUSING SECTION
[0271] 22a FLUID DISCHARGING PATH [0272] 22b FLANGE SECTION [0273]
22c PROJECTION [0274] 22d TERMINAL END PORTION [0275] 50
CLASSIFYING DEVICE [0276] 60, 60A, 60B, 60C LIQUID [0277] 61, 61a,
61b, 61c, 61d CELL AGGREGATE [0278] 62 ISOLATED CELL [0279] 63, 64,
65 CELL AGGREGATE [0280] 66 CELL [0281] 70 DIRECTION IN WHICH
LIQUID FLOWS [0282] 80 WELL PLATE [0283] PS1 FIRST PRINCIPAL
SURFACE [0284] PS2 SECOND PRINCIPAL SURFACE
* * * * *