U.S. patent application number 09/963901 was filed with the patent office on 2002-04-25 for sample preparing arrangement and a method relating to such an arrangement.
Invention is credited to Krozer, Anatol, Otillar, Robert, Ottosson, Britta, Schneeberger, Niklaus, Storek, David.
Application Number | 20020048534 09/963901 |
Document ID | / |
Family ID | 26921983 |
Filed Date | 2002-04-25 |
United States Patent
Application |
20020048534 |
Kind Code |
A1 |
Storek, David ; et
al. |
April 25, 2002 |
Sample preparing arrangement and a method relating to such an
arrangement
Abstract
The present invention relates to an arrangement (10, 20) for
preparing samples (15, 27), submergible in a liquid medium. The
arrangement comprises a section provided with a device (13, 23) for
controllable generation of a magnetic field through influence of a
control signal, said magnetic field being generated to trap at
least part of said samples (15, 27).
Inventors: |
Storek, David; (Goteborg,
SE) ; Schneeberger, Niklaus; (Boudry, CH) ;
Ottosson, Britta; (Molndal, SE) ; Krozer, Anatol;
(Goteborg, SE) ; Otillar, Robert; (San Francisco,
CA) |
Correspondence
Address: |
RICHARD ARON OSMAN
SCIENCE AND TECHNOLOGY LAW GROUP
75 DENISE DRIVE
HILLSBOROUGH
CA
94010
|
Family ID: |
26921983 |
Appl. No.: |
09/963901 |
Filed: |
September 26, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60228015 |
Aug 24, 2000 |
|
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|
Current U.S.
Class: |
506/39 ; 422/130;
422/131; 422/400; 436/174; 436/180 |
Current CPC
Class: |
B01J 2219/00585
20130101; B03C 1/035 20130101; B01J 2219/00317 20130101; B01J
2219/0059 20130101; B01L 2300/0819 20130101; B01L 3/50853 20130101;
G01N 33/54333 20130101; B01J 2219/00648 20130101; B01L 3/502761
20130101; C40B 40/06 20130101; Y10T 436/2575 20150115; B01J
2219/00612 20130101; B01J 2219/00587 20130101; B01J 2219/00596
20130101; B01L 2400/0433 20130101; B01J 2219/005 20130101; B01J
2219/00605 20130101; B01J 2219/00659 20130101; B01J 2219/00439
20130101; B01L 2400/043 20130101; B01J 19/0046 20130101; B01J
2219/0034 20130101; B01J 2219/00689 20130101; Y10T 436/25 20150115;
B01J 2219/00621 20130101; B01J 2219/00722 20130101; C40B 60/14
20130101; B01J 2219/00459 20130101; B01L 2300/049 20130101 |
Class at
Publication: |
422/99 ; 422/100;
422/102; 422/130; 422/131; 436/174; 436/180 |
International
Class: |
B01J 019/00; G01N
031/00 |
Claims
What is claimed is:
1. A microelectromechanical system which uses an ordered array of
magnetically controlled beads to regulate localization of discrete
fractions of a fluid medium at discrete, predetermined elements of
a substrate, said system comprising: a substrate comprising (a) a
surface in contact with a fluid medium and (b) an ordered array of
a plurality of elements, each element comprising a discrete place
on the surface; means for generating controllable, localized
magnetic fields at each element; a plurality of beads, each
disposed in the medium proximate to a corresponding element; means
for trapping the fraction with the beads; a controller operably
coupled to the localized magnetic fields generating means; wherein
the localized magnetic fields generating means controllably
generates magnetic fields through influence of control signals
generated by the controller, wherein said magnetic fields
magnetically move each bead relative to the corresponding element,
and thereby regulate localization of discrete fractions of the
medium at discrete, predetermined elements of the substrate.
2. A system according to claim 1, which uses an ordered array of
magnetically controlled beads to regulate localization of discrete
fractions of a fluid medium at discrete, predetermined elements of
a substrate, said system comprising: a substrate comprising (a) a
surface in contact with a fluid medium and (b) an ordered array of
a plurality of elements, each element comprising a discrete place
on the surface and a corresponding integrated magnetic field
generating device, a plurality of beads, each disposed in the
medium proximate to a corresponding element and adsorbing a
discrete fraction of the fluid medium, a controller operably
coupled to each device; wherein each device controllably generates
magnetic fields through influence of control signals generated by
the controller, wherein said magnetic fields magnetically move each
bead relative to the corresponding element, and thereby regulate
localization of discrete fractions of the medium at discrete,
predetermined elements of the substrate.
3. A system according to claim 2, wherein each element further
comprises an on-chip detector sensitive to the proximity to the
element of the bead or the fraction.
4. A system according to claim 2, wherein the fractions comprise
agents present in the medium, wherein the agents are selected from
the group consisting of optionally derivatized magnetic particles,
chemicals and cells.
5. A system according to claim 2, wherein the localization is
quantitative.
6. A system according to claim 2, wherein each element further
comprises a discrete cavity in the surface, wherein said magnetic
fields independently, magnetically move each bead between an
uncapped position, opening the corresponding cavity to a fraction
of the medium and a capped position, restricting the cavity to the
fraction of the medium, and thereby regulate localization of
discrete fractions of the medium at discrete, predetermined
elements of the substrate.
7. A microelectromechanical system which uses an ordered array of
magnetically controlled beads to regulate localization of discrete
fractions of a fluid medium at discrete, predetermined elements of
a substrate, said system comprising: a substrate comprising (a) a
surface in contact with a fluid medium and (b) an ordered array of
a plurality of elements, each element comprising a discrete place
on the surface and a corresponding magnetically active material, a
plurality of beads, each disposed in the medium proximate to a
corresponding element and adsorbing a discrete fraction of the
fluid medium, a plurality of magnets external to the substrate; a
controller operably coupled to the external magnets; wherein the
external magnets controllably generate magnetic fields through
influence of control signals generated by the controller, wherein
said magnetic fields magnetically move each bead relative to the
corresponding element, and thereby regulate localization of
discrete fractions of the medium at discrete, predetermined
elements of the substrate.
8. A system according to claim 7, wherein each element further
comprises an on-chip detector sensitive to the proximity to the
element of the bead or the fraction.
9. A system according to claim 7, wherein the fractions comprise
agents present in the medium, wherein the agents are selected from
the group consisting of optionally derivatized magnetic particles,
chemicals and cells.
10. A system according to claim 7, wherein the localization is
quantitative.
11. A system according to claim 7, wherein each element further
comprises a discrete cavity in the surface, wherein said magnetic
fields independently, magnetically move each bead between an
uncapped position, opening the corresponding cavity to a fraction
of the medium and a capped position, restricting the cavity to the
fraction of the medium, and thereby regulate localization of
discrete fractions of the medium at discrete, predetermined
elements of the substrate.
12. A system according to claim 1, which uses an ordered array of
magnetically controlled beads to regulate localization of discrete
fractions of a fluid medium at discrete, predetermined elements of
a substrate, said system comprising: a substrate comprising (a) a
surface in contact with a fluid medium and (b) an ordered array of
a plurality of elements, each element comprising a discrete cavity
in the surface and a corresponding integrated magnetic field
generating device, a plurality of beads, each disposed in the
medium proximate to a corresponding cavity, a controller operably
coupled to each device; wherein each device controllably generates
magnetic fields through influence of control signals generated by
the controller, wherein said magnetic fields independently,
magnetically move each bead between an uncapped position, opening
the corresponding cavity to a fraction of the medium and a capped
position, restricting the cavity to the fraction of the medium, and
thereby regulate localization of discrete fractions of the medium
at discrete, predetermined elements of the substrate.
13. A system according to claim 12, wherein each element further
comprises an on-chip detector sensitive to the proximity to the
element of the bead or the fraction.
14. A system according to claim 12, wherein the fractions comprise
agents present in the medium, wherein the agents are selected from
the group consisting of optionally derivatized magnetic particles,
chemicals and cells.
15. A system according to claim 12, wherein the localization is
quantitative.
16. A system according to claim 12, wherein the fractions comprise
agents present in the medium, the agents are optionally derivatized
magnetic particles, and the magnetic fields. in conjunction with
movement of the bead, controllably move one or more of the
particles into or out of the cavity.
17. A microelectromechanical system which uses an ordered array of
magnetically controlled beads to regulate localization of discrete
fractions of a fluid medium at discrete, predetermined elements of
a substrate, said system comprising: a substrate comprising (a) a
surface in contact with a fluid medium and (b) an ordered array of
a plurality of elements, each element comprising a discrete cavity
in the surface and a corresponding magnetically active material, a
plurality of beads, each disposed in the medium proximate to a
corresponding cavity, a plurality of magnets external to the
substrate; a controller operably coupled to the external magnets;
wherein the external magnets controllably generate magnetic fields
through influence of control signals generated by the controller,
wherein said magnetic fields independently, magnetically move each
bead between an uncapped position, opening the corresponding cavity
to a fraction of the medium and a capped position, restricting the
cavity to the fraction of the medium, and thereby regulate
localization of discrete fractions of the medium at discrete.
predetermined elements of the substrate.
18. A system according to claim 17, wherein each element further
comprises an on-chip detector sensitive to the proximity to the
element of the bead or the fraction.
19. A system according to claim 17, wherein the fractions comprise
agents present in the medium, wherein the agents are selected from
the group consisting of optionally derivatized magnetic particles,
chemicals and cells.
20. A system according to claim 17, wherein the localization is
quantitative.
21. A system according to claim 17, wherein the fractions comprise
agents present in the medium, the agents are optionally derivatized
magnetic particles, and the magnetic fields, in conjunction with
movement of the bead, controllably move one or more of the
particles into or out of the cavity.
22. A method of using a system according to claim 2, comprising the
step of controllably generating magnetic fields through influence
of control signals generated by the controller, wherein said
magnetic fields independently, magnetically move each bead relative
to the corresponding element, and thereby regulate localization of
discrete fractions of the medium at discrete, predetermined
elements of the substrate.
23. A method of using a system according to claim 7, comprising the
step of controllably generating magnetic fields through influence
of control signals generated by the controller, wherein said
magnetic fields independently, magnetically move each bead relative
to the corresponding element, and thereby regulate localization of
discrete fractions of the medium at discrete, predetermined
elements of the substrate.
24. A method of using a system according to claim 12, comprising
the step of controllably generating magnetic fields through
influence of control signals generated by the controller, wherein
said magnetic fields independently, magnetically move each bead
between an uncapped position, opening the corresponding cavity to a
fraction of the medium and a capped position, restricting the
cavity to the fraction of the medium, and thereby regulate
localization of discrete fractions of the medium at discrete,
predetermined elements of the substrate.
25. A method of using a system according to claim 17, comprising
the step of controllably generating magnetic fields through
influence of control signals generated by the controller, wherein
said magnetic fields independently, magnetically move each bead
between an uncapped position, opening the corresponding cavity to a
fraction of the medium and a capped position. restricting the
cavity to the fraction of the medium, and thereby regulate
localization of discrete fractions of the medium at discrete,
predetermined elements of the substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35USC120 to U.S.
application Ser. No. 09/938,471, filed Aug. 23, 2001, having the
same title and inventors, which claims the benefit of U.S.
application Ser. No. 60/228,015, filed Aug. 24, 2000, which are
incorporated herein by reference.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates to a chip-based method and
arrangement for preparing, manipulating or detecting samples.
BACKGROUND OF THE INVENTION
[0003] There exists an enormous number of processes occurring in an
organism per unit time and also in each cell of the organism. One
needs therefore fast techniques enabling acquisition of information
in parallel, and effective means of storage and handling of such
information.
[0004] High throughput screening (HTS) examines in parallel as
small samples as possible (so as not to use large amounts of
expensive and rare chemicals) and as many of these as possible,
usually arranged in a dense, ordered solid-phase matrix, often
referred to as a "chip".
[0005] One example of such preparation is given in FIG. 1
(Biophotonics, January/February 2000, Univ. of Wisconsin, Franco
Cerrina, et.al.). According to this technique, a matrix is created
by burning away deposits from certain selected places on a chip,
while depositing additional chemicals on other places. This method,
although fairly fast and cheap, produces a permanent pattern on a
matrix, which will be used up after single experiment. Thus, each
new experiment requires production of a new matrix.
[0006] The number of elements (spots) in a matrix varies depending
on the preparation method. but usually does not exceed 10,000,
although matrices as large as 1,000,000 sites have been reported.
The outcome of each single "experiment" therefore gives at best
10,000 results. In reality this number is much lower (around 20%)
due to the very poor quality of even the best matrices produced to
date.
[0007] Apart from preparation mentioned above a complete HTS-system
has to include also means of detection for the events taking place
in each spot as well as data transfer and evaluation.
[0008] Relevant literature includes: FR 2,781,886; U.S. Pat. Nos.
5,874,219; 5,922.617; 5,755,942; WO 00/43534; WO 00/49382; WO
00/60356; and WO 00/54882.
SUMMARY OF THE INVENTION
[0009] One object of the invention is to present an arrangement
which improves the "one by one" experimentation.
[0010] The technique allows a relatively rapid screening of new
chemicals to be used as drugs, both with regard to their function
and (importantly) with regard to the determination of the side
effects that a given drug might exert, but can also be used in many
other applications such as genome determination, proteomics and
others.
[0011] In this invention, a different route as compared to
above-mentioned prior art is followed. The idea is not to prepare a
ready-to-use-product, which is impossible to modify, but to allow a
user for possibility to prepare its own "experiment". Thus, one
object of the invention is to provide an easy-to-handle platform,
which could be used repeatedly and could be prepared in-house.
Consequently, the invention is not limited to the surface deposits
as are the devices described above (see also FIG. 1), but allows
sample preparation either by surface deposition (at the bottom or
at the walls of a crater) or by utilizing liquid state reactions
allowing reagent contained in the liquid trapped within each well
by a cap to mix with reagents contained in the liquid above the
craters by opening the "lids" (caps) at will.
[0012] In the arrangement according to the invention, it is
relatively easy to change both the dimensions and the number of the
wells. Also the simplicity of the design will allow integrating the
reaction product detection system on-chip and perhaps also the
facility for multi-well deposition of the active substance.
[0013] Another object of the invention is to describe how the
detection limits for the events under study can be improved using
techniques similar to those used for chip production.
[0014] These objects are achieved by the initially mentioned
arrangement, which comprises a section provided with a device for
controllable generation of a magnetic field through influence of a
control signal, said magnetic field being generated to trap at
least part of said samples. Preferably, said device is a coil or a
magnetically active material and it is made of an electrically
conducting material, preferably aluminium. Each device is applied
through a conductor of a current of different strength, whereby the
current amplitude and the number of windings in the coil are
proportional to the strength of the magnetic field.
[0015] According to the first aspect of the invention the
arrangement comprises a cavity provided in a substrate and a lid
for closing said cavity. Preferably, the lid is a magnetic bead.
The bead is directed onto a cavity using external magnets that
create magnetic fields counteracting the field created by the
material deposited around each cavity. Each cavity is surrounded by
a device, which directs said lid using external magnets that create
magnetic fields counteracting the field created by material
deposited around each cavity. The cavities are etched in a silicon
surface and the lid is provided as a large magnetic particle in the
liquid. The particle is attracted to a predetermined cavity when
the coil of said cavity is energised by electric current to produce
magnetic field of spatial attraction. Before sealing off the
cavity, smaller magnetic particles are attracted into the cavity.
The sample is a magnetic particle covered with appropriate
chemical(s). In one embodiment, the arrangement comprises means for
detection of presence of a magnetic capping lid capping a cavity.
In one embodiment, the capping is detected by detecting the change
in inductance in the control circuit, which produces the attractive
magnetic field, whereby the bead acts like a magnetic yoke in a
transformer, increasing the inductance. In another embodiment, the
capping is detected through decrease of electromagnetic radiation
to a detector inside the cavity or by changes of capacitance
between electrodes inside the cavity or near a cavity rim.
[0016] The arrangement may also comprise means for detection of
changes of inductance when a magnetic particle passes through the
opening into or out of a cavity. The indication is determined using
the direction of an externally controlled magnetic field, either by
changing the direction of the electric current flowing through a
coil or flipping an external magnet. Preferably, the particle
contains particular molecular coating, which reacts with the liquid
in that cavity or with the coating adsorbed on the walls of the
cavity.
[0017] The substrate can be made of silicon, Si, or of Si-compound,
such as Si-oxide Si-nitride or Si-carbide, or combinations thereof,
or a suitable polymer, such as polyethylene, polyethylene glycol,
polyethylene oxide, fluorine containing a polymer (PTFE-Teflon), or
silicon containing a polymer.
[0018] According to a second aspect of the invention, the
arrangement comprises a member for generating acoustic waves and
said device on a substrate or carrier. The device and the member
for generating acoustic waves are covered with an insulating layer.
On the insulating layer. a combination of receptor-bead of a
magnetisable material are attached. A sample is provided with a
magnetic portion, which can be attracted towards the receptor. The
combination of receptor-bead attenuate the acoustic wave stronger
than receptors attached to the insulating layer. Preferably, the
surface of the insulating layer is inert to receptors, and the
receptor-bead combination is attached to the surface by magnetic
forces acting on the bead.
[0019] The invention also relates to a method of preparing samples,
by means of an arrangement submergible in a liquid medium, said
arrangement comprising a section provided with a device for
generation of a magnetic field. The method comprises the steps of
connecting a signal to said device and generating a magnetic field
to trap at least part of said samples. To each device is applied a
current of different strength. The arrangement is provided by a
cavity in a substrate. The method comprises the further steps of
arranging a magnetic lid for closing said cavity. directing said
bead onto a cavity using external magnets that create magnetic
fields counteracting the field created by the material deposited
around each cavity, and attracting smaller magnetic particles into
the cavity before sealing off the cavity. Preferably, the sample is
a magnetic particle covered with an appropriate chemical(s).
According to the method it is possible to detect presence of a
magnetic capping lid capping a cavity. The capping is determined by
detecting the change in inductance in the control circuit, which
produces the attractive magnetic field, whereby the bead acts like
a magnetic yoke in a transformer. increasing the inductance. The
capping may also be determined through decrease of electromagnetic
radiation to a detector inside the cavity or by changes of
capacitance between electrodes inside the cavity or near the cavity
rim. According to the method it is possible to detect changes of
inductance when a magnetic particle passes through the opening into
or out of a cavity, and determining said indication using the
direction of an externally controlled magnetic field, either by
changing the direction of the electric current flowing through a
coil or flipping an external magnet.
[0020] According to the method, given a known number of samples in
each cavity and a density of respective coatings, quantitative data
on the number of reaction between the coating on a wall of the
cavity and the coating on a small sample is obtained by counting
the number of samples.
[0021] In particular aspects, the invention provides
embodiments:
[0022] 1. An arrangement (10, 20) for preparing samples (15, 27),
submergible in a liquid medium, characterised in, that the
arrangement comprises a section provided with a device (13, 23) for
controllable generation of a magnetic field through influence of a
control signal, said magnetic field being generated to trap at
least part of said samples (15, 27).
[0023] 2. The arrangement according to embodiment 1, characterised
in, that said device (13, 23) comprises a coil.
[0024] 3. The arrangement according to embodiment 1, characterised
in, that said device comprises a magnetically active material.
[0025] 4. The arrangement according to any of preceding
embodiments, characterised in. that the device comprises an
electrically conducting material, preferably aluminium.
[0026] 5. The arrangement according to any of preceding
embodiments, characterised in. that each device through a conductor
(17) is applied a current of different strength.
[0027] 6. The arrangement according to embodiment 2, characterised
in, that a current amplitude and the number of windings in the coil
are proportional to the strength of the magnetic field.
[0028] 7. The arrangement (10) according to any one of embodiments
1-6, characterised in that said arrangement comprises a cavity (12)
provided in a substrate (11).
[0029] 8. The arrangement according to embodiment 7, characterised
in, that it comprises a lid (14) for closing said cavity (12).
[0030] 9. The arrangement according to embodiment 8, characterised
in, that said lid (14) is a magnetic bead.
[0031] 10. The arrangement according to embodiment 3 and 9,
characterised in, that the bead is directed onto a cavity using
external magnets that create magnetic fields counteracting the
field created by the material deposited around each cavity
(12).
[0032] 11. The arrangement according to embodiment 9, characterised
in, that said lid is a micro-bead introduced in said liquid
medium.
[0033] 12. The arrangement according to embodiment 7, characterised
in, that each cavity is surrounded by a device, which directs said
lid using external magnets that create magnetic fields
counteracting the field created by material deposited around each
cavity (12).
[0034] 13. The arrangement according to embodiment 7, characterised
in, that the cavities are etched in a silicon surface and the lid
is provided as a large magnetic particle (14) in the liquid.
[0035] 14. The arrangement according to embodiment 13,
characterised in, that said particle (14) is attracted to a
predetermined cavity when the coil of said cavity is energised by
electric current to produce magnetic field of spatial
attraction.
[0036] 15. The arrangement according to embodiment 14,
characterised in, that before sealing off the cavity, smaller
magnetic particles are attracted into the cavity.
[0037] 16. The arrangement according to any of preceding
embodiments, characterised in, that said sample (15) is a magnetic
particle covered with appropriate chemical(s).
[0038] 17. The arrangement according to any of preceding
embodiments, characterised in, that the arrangement comprises means
for detection of presence of a magnetic capping lid capping a
cavity.
[0039] 18. The arrangement according to embodiment 17,
characterised in, that said capping is detected by detecting the
change in inductance in the control circuit, which produces the
attractive magnetic field, whereby the bead acts like a magnetic
yoke in a transformer. increasing the inductance.
[0040] 19. The arrangement according to embodiment 17,
characterised in, that said capping is detected through decrease of
electromagnetic radiation to a detector inside the cavity or by
changes of capacitance between electrodes inside the cavity or near
a cavity rim.
[0041] 20. The arrangement according to any of preceding
embodiments, characterised in, that it comprises means for
detection of changes of inductance when a magnetic particle passes
through the opening into or out of a cavity.
[0042] 21. The arrangement according to embodiment 20.
characterised in, that the indication is determined using the
direction of externally controlled magnetic field, either by
changing the direction of the electric current flowing through a
coil or flipping an external magnetic.
[0043] 22. The arrangement according to embodiment 20 or 21,
characterised in, that said particle contains particular molecular
coating, which reacts with the liquid in that cavity or with the
coating adsorbed on the walls of the cavity.
[0044] 23. The arrangement according to any of embodiments 7-16,
characterised in, that the substrate is made of silicon, Si, or of
Si-compound, such as Si-oxide Si-nitride or Si-carbide, or
combinations thereof, or a suitable polymer, such as polyethylene,
polyethylene glycol. polyethylene oxide, fluorine containing a
polymer (PTFE-Teflon), or silicon containing a
[0045] 24. The arrangement according to any of embodiments 1-6,
characterised in, that the arrangement (20) comprises a member (22)
for generating acoustic waves and said device (23) on a substrate
or carrier (21).
[0046] 25. The arrangement according to embodiment 24,
characterised in, that the device and the member for generating
acoustic waves are covered with an insulating layer (24).
[0047] 26. The arrangement according to embodiment 24,
characterised in, that on the insulating layer. a combination of
receptor-bead (25) of a magnetisable material is attached.
[0048] 27. The arrangement according to embodiment 26,
characterised in, that a sample (27) is provided with a magnetic
portion (28), which can be attracted towards the receptor (25,
26).
[0049] 28. The arrangement according to embodiment 26,
characterised in, that said combination of receptor-bead attenuate
the acoustic wave (29) stronger than do receptors attached to the
insulating layer (24).
[0050] 29. The arrangement according to any of embodiments 25-28,
characterised in that said surface of the insulating layer (24) is
inert to receptors, and that the receptor-bead combination is
attached to the surface by magnetic forces acting on the bead.
[0051] 30. A method of preparing samples (15, 27), by means of an
arrangement (10, 20) submergible in a liquid medium, said
arrangement comprising a section provided with a device (13, 23)
for generation of a magnetic field, characterised by connecting a
signal to said device (13, 23) and generating a magnetic field to
trap at least part of said samples (15, 27).
[0052] 31. The method of embodiment 30, characterised in that to
each device is applied a current of different strength.
[0053] 32. The method of embodiment 30, characterised in that said
arrangement is provided by a cavity (12) in a substrate (11).
[0054] 33. The method of embodiment 32, characterised by arranging
a magnetic lid (14) for closing said cavity (12).
[0055] 34. The method of embodiment 33, characterised by directing
said bead onto a cavity using external magnets that create magnetic
fields counteracting the field created by the material deposited
around each cavity (12).
[0056] 35. The method according to any of embodiments 30-34,
characterised by attracting smaller magnetic particles into the
cavity before sealing off the cavity.
[0057] 36. The method according to any of embodiments 30-34,
characterised in that said sample is a magnetic particle covered
with an appropriate chemical(s).
[0058] 37. The method according to any of embodiments 30-35,
characterised by detection of presence of a magnetic capping lid
capping a cavity.
[0059] 38. The method according to embodiment 37, characterised by
detecting said capping by detecting the change in inductance in the
control circuit, which produces the attractive magnetic field,
whereby the bead acts like a magnetic yoke in a transformer,
increasing the inductance.
[0060] 39. The method according to embodiments 37, characterised by
detecting said capping through decrease of electromagnetic
radiation to a detector inside the cavity or by changes of
capacitance between electrodes inside the cavity or near the cavity
rim.
[0061] 40. The method according to any of preceding embodiments,
characterised by detection of changes of inductance when a magnetic
particle passes through the opening into or out of a cavity.
[0062] 41. The method according to embodiment 40, characterised by
determining said indication using the direction of externally
controlled magnetic field, either by changing the direction of the
electric current flowing through a coil or flipping an external
magnetic.
[0063] 42. The method according to any of embodiments 30-41,
characterised by given a known number of samples in each cavity and
a density of respective coatings, quantitative data on the number
of reaction between the coating on a wall of the cavity and the
coating on a small sample is obtained by counting the number of
samples.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] In the following, the invention will be further described in
a non-limiting way under reference to the accompanying drawings in
which:
[0065] FIG. 1 shows an arrangement according to prior art,
[0066] FIG. 2 is a schematic view from above of chip according to
the invention,
[0067] FIG. 3 is a schematic view, showing an enlarged
cross-section along line II-II through a part of the chip according
to FIG. 2,
[0068] FIG. 4 is a schematic view from above of a part of another
chip according to the invention. and
[0069] FIG. 5 is a schematic view, showing an enlarged
cross-section along line IV-IV through a part of the chip according
to FIG. 4.
[0070] FIG. 6 is a schematic view, showing an enlarged
cross-section of a portion of FIG. 5 under (A) no magnetic field,
(B) an attractive field, and (C) a repulsive field.
DETAILED DESCRIPTION OF THE PARTICULAR EMBODIMENTS
[0071] The basic idea of the present invention is to create an
enclosure or a crater (a well), provided with a lid, which can be
opened and closed by a "lid". A user can control the lid and the
device is intended to be submerged in a liquid medium. By operating
the lid, the enclosed volume becomes separated from the
surroundings. That means, the liquid stored in the crater,
particles suspended therein, and/or material that adheres to the
craters inner surface are not affected by subsequent changes that
occur in the surroundings while the lid is closed. These changes
might be a different chemical composition of the liquid, light
shining on the crater chip, or other solids in the surrounding
liquid. The lid may or may not be completely liquid-tight but
mixing of the liquid outside a crater with the liquid contained
inside a well will be dramatically slowed. Hence, solids and
liquids will be well separated between inside and outside, by the
lid.
[0072] FIGS. 2 and 3 illustrate a first example of an arrangement
according to the invention. FIG. 2 illustratess an enlarged
schematic view of a part of chip 19 comprising a number of sample
collecting arrangements 10. Each sample collecting arrangement
comprises a cavity (crater. pocket, well) 12 provided in a
substrate 11 and means 13 to control the cap (lid, cover) 14. Each
control means 13 is connected to controller 18 (FIG. 3) through
connections 17. An insulating layer (111) and an on-chip detector
(112) are also shown.
[0073] FIG. 3 is a schematic cross-section through the device 10.
However, the device 10 is shown in a stage where samples 15 are
collected and the crater 12 is closed by means of the lid or
closure 14. The samples in this particular case are magnetic
particles of diameter(s) much smaller than the diameter of the lid,
covered with appropriate chemical(s)
[0074] In this embodiment, the lid control means 13 comprise
electrically actuated coils and the lid 14 is a magnetizeable
bead.
[0075] By making many craters 12, all with individually controlled
lids 14, different types of mixing of solids dispensed in a liquid
and/or liquids can be achieved at the same time. As different
liquids/solids are introduced to the outside of the craters only
user-selected craters with open lids will be reached for the mixing
by the liquids/solids external to the closed craters.
[0076] The dimensions and the shapes of each crater 12 can of
course vary within a large interval both with respect to its
diameter and depth. The craters can have circular cross-section.
e.g. having about 50 .mu.m deep with the diameters of approximately
100 .mu.m. It is relatively easy to produce craters with dimensions
ranging from few .mu.m and larger and with depth ranging from few
.mu.m and up to several hundreds of .mu.m, having, e.g. square
shapes.
[0077] The material of the substrate can be silicon and the
manufacturing process may include micro-machining, similar to the
process of making microprocessors or memories chips. A device may
contain from several hundreds of craters on a single piece of
silicon, providing a so-called chip. Of course tens of thousands of
craters on commercial units can be arranged.
[0078] Preferably, the lid is a micro-bead introduced in a liquid.
The lid-actuation mechanism. i.e. the closing and the opening of
each of the craters is performed using switchable magnetic fields
that influence the motion of the introduced beads. The magnetic
fields are created using the coils 13 deposited around each
crater.
[0079] The coils 13 surrounding each of the craters are made of an
electrically conducting material. In the preferred embodiment the
conductor is made of aluminium, Al, but any electrical conductor
can be used. Preferably, each coil is accessible through
electrically conducting leads so that a current of different
strength can be applied separately to each coil. The current
amplitude and the number of windings in the coil are proportional
to the strength of the magnetic field, which can thus be varied.
Clearly, it is possible to change the number of windings in the
coils surrounding each crater as well as their width and thickness
within a broad range of dimensions. Preferably but not exclusively,
coils can have from 2 and up to 10 windings.
[0080] In an alternative embodiment, instead of the coils 13, the
control means can be substituted by a magnetically active material
surrounding each crater and direct the beads using external magnets
that will create magnetic fields counteracting the field created by
the material deposited around each crater 12.
[0081] Preferably, the craters are etched in the silicon surface
and the lid is provided by a large magnetic particle 14 in the
liquid. Thus, particle 14 can be attracted to the crater of choice
when the coil of this crater is energised by electric current to
produce magnetic field for spatial attraction. Before sealing off
the crater of choice, however, it is also possible to attract
smaller magnetic particles into the crater. To attract the smaller
magnetic particles 15 to the crater we energize the coil by leading
electric current through it. When the coil is energized, a magnetic
field is established. This field will attract the magnetic particle
15 from the liquid. These smaller particles have higher mobility in
the liquid compared to the mobility of larger particles and will
thus reach crater faster than the larger lids. The large
lid-particle will cap the crater at a later stage. Preferably, as
large particles commercially available magnetic particles such as
ferromagnetic or super-paramagnetic having about 100 micrometers in
size can be used. while the size of the smaller particles is much
smaller than the crater's size. There are other dimensions and
particle types on the market and the invention is applicable to a
broad range of particle sizes, shapes and materials.
[0082] To open a closed crater, a repelling field is generated
either externally or by inverting the direction of the current
flowing through the coil. It is also possible to terminate the
current through the coil, whereby the particle may be released due
to shear force from the flowing liquid or due to gravitational
forces if the craters are positioned "upside down".
[0083] The simple actuation of the crater lid using current
controlled magnetic field(s) and the large number of craters on a
chip makes it necessary that the chip is operated automatically
through controlling arrangement. The chip is preferably provided
with an interface device that establishes electrical connection
with the chip and provides the handling of the surrounding fluid
with the beads and chemicals. After use the chip may be removed for
cleaning and reuse or disposal. The interface device will be
connected to a computer equipped with suitable software to control
the sequence of operations on the craters and the liquid handling
system. The software will also provide an interface for the user to
establish the process sequence and to plan the states of the crater
lids in each sequence.
[0084] Detection of a magnetic capping bead can also be done. It is
important to obtain feedback on which craters are capped. The
presence of a magnetic capping bead, in place over a crater can be
detected by the change in inductance in the electric circuit, which
produces the attractive magnetic field. The bead acts like a
magnetic yoke in a transformer, increasing the inductance. A
resonant, or other, circuit can then detect this inductance
change.
[0085] The presence of the capping bead can be detected by various
other schemes, like the decrease of electromagnetic radiation to a
detector inside the crater or by changes of capacitance between
electrodes inside the crater or near the crater rim.
[0086] Another possible application along similar lines is the
detection of changes of inductance when a small magnetic sphere
passes through the opening into a well. Using the arrangement
according to the invention it is possible to determine whether a
sphere is entering the well or if it is leaving the well. This is
determined using the direction of externally controlled magnetic
field (either by changing the direction of the electric current
flowing through a coil or flipping an external magnetic field
creating device by other means). Such a sphere may contain
particular molecular coating, which will react with the liquid in
that well or with the coating adsorbed on the walls of the crater.
Given one knows the number of spheres in each well and the density
of the respective coatings quantitative data on the number of
reaction between the coating on the wall and the coating on a small
bead can be obtained by simply counting the spheres.
[0087] Following non-limiting examples are given for simplifying
the understanding of the invention: According to a first example
liquid A containing magnetic beads is introduced. User selected
craters 12 are energized and hence capped. The remaining beads are
flushed away with a cleaning liquid. Now liquid B is introduced,
containing small (much smaller than the capping beads) particles,
called X, made of a material interesting to the user. Only uncapped
craters will accept X. Then, more magnetic beads are introduced and
selected craters are capped, trapping X. Cleaning liquid will flush
all excess away. A liquid containing chemical reagent Y can then be
introduced and some craters are opened. X and Y are allowed to mix
and react, but only in the user-selected areas. This reaction can
be followed using sensing techniques, which can easily be
incorporated into the system, for example using optical techniques.
Other possible novel detection techniques easily incorporated into
the present embodiment are mentioned below.
[0088] In a second example, a substance is attached to the craters
inner surface. In a repeating sequence some craters are closed by
the beads and the others are exposed to a reactive chemical A.
After the reaction the chemical is flushed and some craters are
exposed to another chemical B. So there will be craters that have
been exposed to A and B, some to A, some to B, and some to neither.
This process can be repeated with many chemicals producing very
large numbers of differently modified substances residing in
different locations (craters) of choice. With a sequence of 10
different chemicals, for example, more than 1000 different
combinations are obtained. In particular, this could be used to
synthesize DNA strands or (using appropriate well-known techniques)
to investigate the function(s) of different proteins.
[0089] Yet another application is to lock cells in the wells filled
with different chemicals and monitor the reaction of cells (cell
proliferation, differentiation, spreading or others) to these
chemistries. This would enable, for example a fast high throughput
screening of drugs.
[0090] The arrangement may also be used separately, one-by-one, for
example to deliver a certain chemical or chemicals locally at a
certain place or places in a reaction vessel, and monitor reaction
products locally, or to deliver a drug inside a body.
[0091] Another field of possible applications of the device has
been triggered by something generally referred to as a "low
throughput screening" (LTS). LTS is often used when the amount of
required information is smaller but in addition one wants to obtain
some quantitative information about concentrations of analyses or
number of reactions that occur during certain time at certain
amounts of reagents. The idea behind LTS has much in common with
another timely idea often used to day: an "electronic tongue".
Electronic tongue is a device that enables one to determine
components in a liquid. These components can then be associated
with certain tastes (sweet, sour, etc. or combinations thereof). To
determine the content of simple liquids in a liquid mixture, for
example % of sugar dissolved in a cup of tea along with the amount
of tea used to prepare this cup, and even perhaps different tea
blends used. To acquire knowledge about all these requires
performing several experiments with constituents that react
differently to different tea blends and to different amounts of tea
from each blend that has been used, as well as to the amounts of
sugar being dissolved in this tea. All these can be made by LTS
methods using our equipment and choosing appropriate reagents
different for each crater and letting these first to react with a
"standard" samples ("learning the tongue" to recognise certain
non-mixed liquids) and later exposing these samples to mixtures of
different tea blends with or without sugar. Appropriate data
processing from the outcome compared with the results obtained on
standard samples enables one often to obtain information about tea
blends used and the amount of sugar dissolved.
[0092] The device is not limited to spheres or coils for creation
of magnetic fields that direct beads nor is it limited to the use
of beads, and other shapes can be used. Finally it is not limited
to the use of silicon technology to fabricate the crater matrices;
other materials can be used for this purpose.
[0093] Following are additional, non-limiting, examples of
different crater preparation techniques and materials of use paired
with its utilisation:
[0094] The general idea behind these examples is to manipulate
small particles in order to bring them to a chosen place on the
surface of the substrate using magnetic field(s) as a driving force
for particle manipulation. The surface of the substrate may be
either patterned in a particular manner, or not. When the substrate
is patterned and the pattern consists of craters some particles are
used preferably as caps or lids to close each crater as described
earlier. When the substrate is left without a pattern or patterned
in a different manner (see below for an example) the particles can
be used mainly as a way to enhance sensitivity of detection of the
processes taking place in the device.
[0095] The magnetic force to manipulate the particles can be
created using coils as described above. but it also may be created
using externally applied magnets. In the former case the field
strength (and thus the magnitude of the forces) is determined
primarily by the number of windings in the coil and the magnitude
of the electric current. In the latter case it is possible to
control the magnitude of the magnetic force by appropriate choice
of magnet position and strength.
[0096] The substrate may be made of silicon (described above), Si,
or of Si-compound, e.g. Si-oxide Si-nitride or Si-carbide, or
combinations thereof. It may also consist of thin self-supporting
Si, or of a Si-compound, with another film of suitable thickness
(for example few micrometers), such as ZnO, evaporated onto its
surface. This additional film is needed if the device is to work as
an acoustic wave device for detection.
[0097] The substrate may also be fabricated using other material
than silicon. For example a suitable polymer, e.g. polyethylene,
polyethylene glycol, polyethylene oxide, fluorine containing a
polymer (PTFE-Teflon), or silicon containing a polymer, may be used
as a substrate material.
[0098] When patterning the substrate different techniques may be
used depending on the substrate material and the pattern. Thus, Si
and Si-compounds are suitably patterned applying well-known
techniques from the semiconductor fabrication. When patterning
polymers one can use known techniques like polymer stamping or
moulding.
[0099] The patterns on the substrate are not limited to craters.
For example when using the device as an acoustic wave detector one
may produce matrices consisting of many interdigitated patterns
needed for acoustic wave generation and detection. FIGS. 4 and 5
show one example of such a device.
[0100] The coils can be patterned using well-known techniques such
as electroplating, vapour deposition or sputter.
[0101] In the following, few non-limiting examples of how similar
techniques based on the magnetic manipulation of beads can be used
to enhance detection sensitivity of chemical reactions are
described:
[0102] A single site of a matrix of the Surface Acoustic Wave, SAW,
devices is shown in FIGS. 4 and 5 Each device 20, comprises an
arrangement 22 for generating acoustic waves and magnetic field
control means 23 on a substrate or carrier 21. The arrangement for
generation and detection of acoustic waves comprises two
finger-shaped, reversed arranged conductors 221 and 222 provided on
both sides of the control means 23. The control means 23 is
arranged as a coil connected to a controller (not shown) as
described in conjunction with foregoing embodiment. The coil and
the arrangement for generating acoustic waves are covered with an
insulating layer 24 (FIG. 5), made of, e.g. glass or plastic, or a
biomolecular layer. Onto this insulating layer, (biomolecular)
"receptors" 25 can be adsorbed. The receptors, 25, can be used in
their native state and adsorb spontaneously onto a suitably
prepared insulating layer, 24. They may also be pre-adsorbed onto
small magnetic beads, 28, and the whole complex (magnetic
bead-receptor) can be attracted to the surface of the SAW--device
by magnetic field created by letting the current pass through the
coil 23. The beads+receptors attenuate the acoustic wave, 29, many
times stronger compared to the case when native receptors are
attached to the insulating layer 24 and thus much lower
concentrations of adsorbates at the surface are needed when the
receptor-bead complexes are adsorbed.
[0103] Another advantage of such configuration is that it allows
for the regeneration of the device. It may be possible to
manufacture the surface of the insulating layer, 24, inert to
receptors themselves, so that the receptor and bead complex is
attached to the surface by magnetic forces acting on a bead. Once
the investigation is completed the magnetic field can be removed
(or the direction of the field changed using external magnet)
causing the receptor and bead complex to desorb. This will leave
the surface in its as-prepared state ready for another
investigation.
[0104] If one wishes to study the reaction between these receptors
and appropriate "donors", 27, the latter may be introduced in their
native stage (27), or coupled to a magnetic bead 28.
[0105] Again, coupling the donors to magnetic beads allows for
larger attenuation of acoustic wave when the acceptor-donor
reaction has occurred (irrespective from whether this reaction
caused additional donor-derived beads to be adsorbed on the surface
or whether it caused the desorption of the reaction
product-receptor+bead/donor+bead) which decreases the necessary
number of reaction needed for a given sensitivity of the
device.
[0106] Since the beads influence the propagation of acoustic waves
stronger than do the molecules, which react, to each other one
obtains manifold enhancement of the detection of the chemical
reaction involving these molecules. One particular, but far from
the only one, example of such reaction is the antibody-antigene
reaction. Another example would be DNA-complementary DNA (or PNA)
reaction. The reaction may occur spontaneously over many sites of
the matrix, leaving other sites unreacted. By separately applying
the magnetic field so as to remove particles from each site one
obtains (i) a pattern over sites where reaction did take place. and
(ii) a quantitative information about the number of reaction that
did take place at each site (see. FIG. 6A-6C).
[0107] Another way to use the matrix with interdigitated electrodes
is as a capacitor; a certain number of electrode pairs will be
considered as a single site and will constitute a capacitor. One
prepares each site of the matrix differently, i.e. using different
chemistries. By directing beads. with specific molecules attached
to them, to these sites using magnetic field, or withdrawing
particles from these sites, one is able to perturb the dielectric
constant of a layer close to the surface and therefore produce
large changes of the capacitance of the device compared to
attachment of only (bio)molecules.
[0108] The invention is not limited the shown embodiments but can
be varied in a number of ways without departing from the scope of
the appended claims and the arrangement and the method can be
implemented in various ways depending on application, functional
units, needs and requirements etc.
* * * * *