U.S. patent application number 09/784799 was filed with the patent office on 2001-08-23 for biochip.
Invention is credited to Tanaami, Takeo.
Application Number | 20010016321 09/784799 |
Document ID | / |
Family ID | 18567136 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010016321 |
Kind Code |
A1 |
Tanaami, Takeo |
August 23, 2001 |
Biochip
Abstract
A biochip which is extremely safe and enables reduction of cost
of testing and which comprises in sequence from opening of a blood
collecting tube thereof: a collection block for retaining collected
blood; a preprocessing block for deriving a target from the
collected blood; and a substrate on which probes are deposited in
arrays and the opening is closed airtight with a rubber plug.
Inventors: |
Tanaami, Takeo; (Tokyo,
JP) |
Correspondence
Address: |
MOONRAY KOJIMA
BOX 627
WILLIAMSTOWN
MA
01267
US
|
Family ID: |
18567136 |
Appl. No.: |
09/784799 |
Filed: |
February 15, 2001 |
Current U.S.
Class: |
435/6.11 ;
422/400 |
Current CPC
Class: |
B01J 2219/00722
20130101; B01J 2219/00702 20130101; A61B 5/14532 20130101; B01J
2219/00585 20130101; C40B 40/06 20130101; B01J 2219/00605 20130101;
B01J 2219/00659 20130101; B01J 2219/00608 20130101; B01J 2219/00529
20130101; B01J 2219/00596 20130101 |
Class at
Publication: |
435/6 ; 422/57;
422/102 |
International
Class: |
G01N 031/20 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 22, 2000 |
JP |
2000/044,384 |
Claims
What is claimed is:
1. A biochip comprising, in sequence from opening of a blood
collecting tube thereof: collection means for retaining collected
blood; preprocessing means for deriving a target from said
collected blood; and substrate means on which probes are deposited
in arrays, wherein said opening is closed airtight.
2. The biochip of claim 1, wherein said collection means comprises
means for introducing said collected blood into said preprocessing
means by natural diffusion.
3. The biochip of claim 1, wherein said substrate means is located
in a section which is kept under negative pressure against said
collection means so that blood collected in said collection means
is introduced into said preprocessing means by osmosis based on
said negative pressure.
4. The biochip of claim 1, wherein said substrate means is located
in a section which is subjected to evacuation and thereby
depressurization so that blood collected in said collection means
is introduced into said preprocessing means by osmosis based on
said evacuation.
5. The biochip of claim 1, further comprising means for applying a
voltage externally so that blood collected in said collection means
is introduced into said preprocessing means by electrophoresis.
6. The biochip of claim 1, wherein said preprocessing means derives
DNA from blood collected in said collection means and said samples
are also DNA.
7. The biochip of claim 1, wherein said preprocessing means drives
RNA from blood collected in said collection means and said samples
are also RNA.
8. The biochip of claim 1, wherein said preprocessing means derives
protein from blood collected in said collection means and said
samples are also protein.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] This invention relates to a biochip for testing such
substances as DNA, RNA or protein; and, more particularly, to a
biochip that is safe and reduces cost of testing.
[0003] 2. Description of the Prior Art
[0004] A biochip, such as a DNA chip, comprises several thousand to
several hundred thousand types of known DNA segments, also referred
to as DNA probes, deposited in a plurality of arrays on a
substrate. If a solution containing an unknown DNA segment, also
referred to as a DNA target, is caused to flow onto such a DNA
chip, DNA segments of the same type combine with each other. This
property is utilized so that a DNA probe, wherein such combination
has taken place, is examined using a biochip reader, and thus, the
sequence of the DNA target, for example, is determined.
[0005] FIG. 1 shows an example of hybridization seen in a biochip,
wherein six DNA probes DN01, DN02, DN03, DN04, DN05 and DN06 are
deposited in a plurality of arrays on a substrate SBO1, thus
forming a DNA chip. A DNA target UN01 is previously marked with a
fluorescent marker LM01. When hybridized to the DNA chip, the DNA
target combines with a DNA probe whose sequence is complementary.
For example, the DNA target UN01 combines with DNA probe DN01, as
indicated by CB01. Using a biochip reader, excitation light is
irradiated at the DNA chip, thus hybridized, in order to detect
fluorescent light produced at the fluorescent marker. Hence, it is
possible to know which of the DNA probes the DNA target has
combined with. For example, in an image SI01 resulting from
scanning a DNA chip, fluorescent light is observed at the spot LD01
whereat the DNA combination CB01 was produced.
[0006] FIG. 2 shows a DNA chip as the biochip, wherein the biochip
comprises a substrate 1, on which known DNA segments are deposited
in a plurality of arrays (referred to as "substrate 1"); a
cartridge 2 wherein the substrate 1 is housed and to which a
solution containing a DNA target previously marked with a
fluorescent marker is introduced; and an inlet opening 3 formed on
cartridge 2 through which a solution is introduced. Cartridge 2
comprises a material which is permeable to both excitation light
and fluorescent light produced thereby at the marker. Cells CL11,
CL12, CL13, CL14, CL15 and CL16, in each of which a plurality of
DNA probes of the same type are placed, are deposited in arrays on
substrate 1.
[0007] The method of testing DNA or other substance using the
biochip of FIG. 2 is described with reference to FIGS. 3 and 4,
wherein FIG. 3 shows an example of introducing solution into
cartridge 2, and FIG. 4 shows an example of scanning a hybridized
DNA chip using a biochip reader to determine the sequence of target
DNA, for example. FIG. 3 shows components 1 to 3 which are the same
as those in FIG. 2.
[0008] In a first step, blood is collected using a syringe from a
person being tested. A solution that was preprocessed is then
introduced through an inlet opening 3 into cartridge 2. Solution
infusion means or device 4, such as a pipette, is loaded with a
preprocessed solution 5. The tip of solution infusion device 4 is
inserted in inlet opening 3 and solution 5, inside the device 4, is
injected into cartridge 2. The preprocessing refers to a series of
processes wherein lymphocytes are separated from the collected
blood, and then DNA is extracted from the separated lymphocytes,
and finally, the extracted DNA is marked with a fluorescent
marker.
[0009] In a second step, substrate 1 is soaked with solution
introduced into cartridge 2 to allow a DNA target in the solution
to hybridize with DNA probes placed in each cell on substrate
1.
[0010] In a final step, as shown in FIG. 4, hybridized substrate 1
is scanned using a biochip reader 50 so that, for example, the
sequence of the DNA target is determined.
[0011] In FIG. 4, components 1 to 3 and cells CL11, CL12, and CL13
are similarly denoted as in FIG. 3. In addition, light emitted from
a light source 6, such as a laser light source, is reflected by a
dichroic mirror 7, as excitation light and focused through an
objective lens 8 onto cells on substrate 1. For example, excitation
light is focused onto cell CL12 in FIG. 4. Fluorescent light
produced at cell CL12 on substrate 1 becomes parallel light at it
travels through objective lens 8 and is projected onto dichroic
mirror 7. The fluorescent light, thus projected, is transmitted
through dichroic mirror 7. The fluorescent light thus transmitted
then travels through a filter 9 and is condensed onto an optical
detector 11 by a lens 10.
[0012] The spots, whereon excitation light is focused, are scanned
by a drive means (not shown). For example, cartridge 2 or biochip
reader 50 itself is scanned so that excitation light is irradiated
at the remaining cells CL11 and CL13 on substrate 1. Hence, it is
possible to determine the sequence of a DNA target by identifying
the position of a cell on substrate 1 where fluorescence takes
place.
[0013] Recently, however, test samples, such as blood, have been
found to be contaminated with a virus, such as HIV. Hence, there is
a growing tendency, for safety reasons, to not recycle various
medical devices, such as syringes, for cleaning or sterilization.
Instead, disposable devices are preferred. In contrast, the method
of introducing a solution, such as shown in FIG. 3, involves the
risk of the human operator or testor becoming infected by a virus,
such as HIV, as result of accidental contact with the solution.
This risk is due to the transfer of the solution from the solution
infusion device 4, or the like to cartridge 2.
[0014] Another problem is that the cost of testing is substantial
since more than one type of medical equipment or device must be
disposed of, including syringes, devices and appliances used for
preprocessing purposes, solution infusion devices, DNA chips,
etc.
SUMMARY OF THE INVENTION
[0015] Accordingly, an object of the invention is to overcome the
aforementioned and other deficiencies, disadvantages, and problems
of the prior art.
[0016] Another object is to provide a biochip which is extremely
safe and enables great reduction in cost of testing.
[0017] The foregoing and other objects are attained in the
invention, which encompasses a biochip collection means for
retaining collected blood; preprocessing means for deriving a
target from the collected blood; and substrate means on which
probes are deposited in arrays with the opening thereto being air
tight.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic view depicting a prior art example of
hybridization seen in a biochip.
[0019] FIG. 2 is a schematic top, cross-sectional view depicting a
prior art biochip.
[0020] FIG. 3 is a schematic view depicting introduction of a
solution into a cartridge.
[0021] FIG. 4 is a schematic view depicting scanning of a
hybridized DNA chip using a biochip reader to determine sequence of
target DNA.
[0022] FIG. 5 is a cross-sectional view depicting an illustrative
embodiment of the invention.
[0023] FIG. 4 is a schematic view depicting application of the
invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0024] FIG. 5 shows a DNA chip (also called a biochip) 51
comprising a blood collecting tube 12, instead of a conventional
split tube, which is inserted in a syringe cylinder in order to
collect blood and is permeable to excitation light and fluorescent
light produced thereby at a fluorescent marker. A substrate 16, on
which DNA probes are deposited in arrays as samples,(called
"substrate 16) is disposed in the innermost section (see right end
area) of blood collecting tube 12. Also, a preprocessing block 15,
wherein the preprocessing previously described above, is carried
out, is disposed in the intermediate section (see middle area) of
blood collecting tube 12. Space in the outermost (see left end
area) of blood collecting tube 12 serves as a collection block 14
for temporarily storing collected blood. The innermost section of
tube 12 is kept under negative pressure against collection block 14
or is kept under vacuum, for example, and a rubber plug 13, whose
middle area has a thin wall through which a needle can pierce, is
disposed within the opening of tube 12 in order to make the tube
air tight.
[0025] Cells CL21, CL22, CL23, each having a plurality of DNA
probes deposited therein are disposed in a plurality of arrays on
substrate 16 as shown in FIG. 5.
[0026] The embodiment of FIG. 5 will now be described with regard
to application and operation with reference to FIG. 6, wherein
rubber plug 13 and DNA chip 51 are shown. A blood collecting needle
18 is disposed on the side opposite to the opening of syringe 17
and has two pierceable ends on opposite ends thereof, and labeled
ND11, ND12. Instead of a split conventional tube, a DNA chip 51 is
inserted through the opening of syringe 17. At this point, one end
ND12 of needle 18 pierces through the middle area of rubber plug 13
on DNA chip 51 so that the end of the needle 18 is connected to DNA
chip 51 As shown in FIG. 6, an arm AM11 of a person being tested is
pricked with the other end ND11 of needle 18. Hence, blood is
collected through needle 18 into collection block 14 of FIG. 5, for
example, but not shown in FIG. 6, of DNA chip 51 so that blood
collection is provided.
[0027] After blood is collected, blood collection needle 18 is
removed from the arm AM11 of the patient and DNA chip 51 is removed
from syringe 17. At this point, a pin hole, at a point in rubber
plug 13, whereat needle ND12 pierced the plug 13, automatically
closes due to the elasticity of the rubber plug 13, so that the
blood collecting tube 12 is maintained air tight.
[0028] The collected blood in collection block 14 is then caused to
infitrate toward the innermost section of tube 12 under negative
pressure against collection block 14 (see FIG. 5). Thus, blood is
introduced into preprocessing block 15, whereat a series of
processes are carried out, such as, for example, lymphocytes are
separated from the collected blood, DNA is extracted from the
separated lymphocytes, and the extracted DNA is marked with a
fluorescent marker, as described hereinbefore.
[0029] The preprocessed DNA is caused to infiltrate rightward into
the innermost section of blood collecting tube 12, under negative
pressure exerted against collection block 14. The collected blood
is thus introduced into the right end area section where substrate
16 is located. Then, a DNA target, marked with a fluorescent
marker, is hybridized with DNA probes so that DNA segments whose
sequences are complementary combine with each other.
[0030] Moreover, excitation light is irradiated at substrate 16,
thus hybridized, using the biochip reader discussed before, and
fluorescent light, produced at the fluorescent marker, is detected.
Hence, it is possible to determine which of the DNA probes, the DNA
target has combined with. For example, the excitation light of a
biochip reader (not shown) indicated by LB11 in FIG. 5, is focused
with an objective lens OL11 onto a cell CL22 on substrate 16. Then,
by detecting fluorescent light LM11 produced at cell CL22, the DNA
target is identified.
[0031] Then, upon completion of the testing, advantageously, all
that remains to be done is to dispose of syringe 17 and DNA chip
51. In contrast, with the prior art devices and methods, a larger
number of devices and equipment must be disposed of, such as those
devices used for preprocessing, and solution infusion devices.
Hence, advantageously, with the invention, a substantial cost
reduction is attained for testing.
[0032] The biochip of the invention also eliminates the need for a
human operator to transfer the collected blood to the DNA chip.
Hence, with the invention, the human operator avoids the risk of
being infected with a virus, such as HIV, as a result of accidental
contact with the collected blood. Thus, with the invention, safety
is enhanced.
[0033] Accordingly, the biochip of the invention comprising a blood
collecting tube 12, which includes a collection block 14, a
preprocessing block 15, and a substrate on which probes are
deposited in arrays, is safe to use and reduces by a considerable
amount the cost of testing.
[0034] Although a DNA chip is described as the biochip in the
discussion of FIGS. 5 and 6, the invention is not so limited. The
biochip may be of such types as an RNA, protein, or sugar chain
samples deposited in arrays on a substrate.
[0035] In the case of RNA chips, the RNA samples undergo
hybridization similar to the DNA samples, whereas the protein
samples are submitted to an antigen-antibody reaction. In either
case, a probe acts to combine with a target.
[0036] Also, the area where substrate 16 is located, is maintained
under negative pressure against collection block 14 to enable
introducing of a test sample of blood from collection block 14 to
the preprocessing block 15. However, the invention is not limited
to such a method.
[0037] One alternative method is to form electrodes on both ends of
preprocessing block 15 and applying a voltage externally
thereacross, so that blood, or the like, is introduced by
electrophoresis. For example, DNA is introduced in a direction from
preprocessing block 15 to substrate 16 when the polarities of a
voltage source VS11 (in FIG. 5) are such that substrate 16 side
(right) of voltage source VS11 is positive and the collection block
14 side (left) is negative. This is due to the fact that the DNA is
negatively charged when the biochip is a DNA chip.
[0038] Another alternative method is to simply use natural
diffusion caused by osmotic pressure to introduce blood or the
like.
[0039] A further alternative method is to provide innermost section
(right end area) of tube 12 with an evacuation port so as to
evacuate the innermost section externally and hence introduce blood
or the like by osmosis.
[0040] Although fluorescent light detection, using a fluorescent
marker, is applied in the embodiment of FIG. 5, an alternative
method can be used to detect electric current changes corresponding
to hybridization or by conducting mass analysis. In the method
based on electric current changes, for example, a molecule known as
an inter-currenter is slipped into a double chain after
hybridization. Then, an electric current is measured since it only
flows through the electrodes where hybridization has taken place.
In the case of mass analysis, ionized DNA molecules picked from
each cell are moved in a vacuum and the moledular weight thereof is
determined from the difference in time each DNA molecule arrives at
a given electrode.
[0041] The invention enjoys the following and other advantages. The
invention comprises a collection block, a preprocessing block, and
a substrate on which probes are deposited in arrays, all disposed
in a blood collecting tube whereby need for a human operator to
transfer the collected blood to a biochip is eliminated so that
risk of being infected with a virus, such as HIV, as a result of
accidental contact with the collect blood is substantially
eliminated and hence safety is enhance.
[0042] Another advantage is that after completion of testing, only
the syringe and biochip need be disposed of. In contrast, the prior
art requires disposal of multiplicity of devices and equipment,
such as those used for preprocessing and solution infusion. Hence,
advantageously, the invention provides a simple testing method
which is inexpensive.
[0043] According to an aspect of the invention, a preprocessing
block derives DNA from blood collected in a collection block. Then,
since samples deposited in arrays on a substrate are also samples
of DNA, a DNA probe and a DNA target, whose sequences are
complementary, combine with each other as a result of
hybridization. Hence, it is possible with the invention to readily
and simply determine the sequence of the DNA target.
[0044] According to another aspect of the invention, a
preprocessing block derives RNA from blood collected in a
collection block. Then, since samples deposited in arrays on the
substrate are also samples of RNA, an RNA probe and an RNA target
whose sequences are complementary combine with each other as a
result of hybridization. Hence, it is possible with the invention
to determine simply and reliably the sequence of the RNA
target.
[0045] According to a further aspect of the invention, a
preprocessing block derives protein from blood collected in a
collection block. Then, since samples deposited as arrays on a
substrate are also samples of protein, a protein probe and a
protein target whose sequences are complementary combine with each
other as a result of antigen-antibody reaction. Hence, it is
possible with the invention to simply and reliably determine the
sequence of the protein target.
[0046] The foregoing description is illustrative of the principles
of the invention. Numerous extensions and modifications thereof
would be apparent to the worker skilled in the art. All such
extensions and modifications are to be considered as part and
parcel of the invention.
* * * * *