U.S. patent application number 11/280853 was filed with the patent office on 2006-09-21 for optical biodiscs with reflective layers.
Invention is credited to Horacio Kido, Jorma Antero Virtanen, Jim V. Zoval.
Application Number | 20060210449 11/280853 |
Document ID | / |
Family ID | 26940031 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060210449 |
Kind Code |
A1 |
Zoval; Jim V. ; et
al. |
September 21, 2006 |
Optical biodiscs with reflective layers
Abstract
An optical biodisc has a substrate, a first reflective layer
over the substrate, an opening in the first reflective layer for
receiving an investigational feature, and a second reflective layer
over the opening for reflecting light transmitted through the
substrate.
Inventors: |
Zoval; Jim V.; (Lake Forest,
CA) ; Kido; Horacio; (Niland, CA) ; Virtanen;
Jorma Antero; (Irvine, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
26940031 |
Appl. No.: |
11/280853 |
Filed: |
November 15, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09999274 |
Nov 15, 2001 |
6965433 |
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11280853 |
Nov 15, 2005 |
|
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60249391 |
Nov 16, 2000 |
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60257705 |
Dec 22, 2000 |
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Current U.S.
Class: |
422/400 ;
356/246; 422/82.09; 435/287.2; 435/288.5; 435/288.7; 435/5;
435/6.19; 436/164 |
Current CPC
Class: |
B01J 2219/00648
20130101; C40B 40/06 20130101; C40B 50/14 20130101; B01J 2219/00637
20130101; B01L 2200/12 20130101; B01L 2300/0887 20130101; B01J
2219/0061 20130101; B01J 2219/00585 20130101; B01J 2219/00695
20130101; B01J 2219/00707 20130101; G01N 35/00069 20130101; B01J
2219/005 20130101; B01J 2219/00317 20130101; C40B 60/14 20130101;
B01J 19/0046 20130101; B01L 2300/168 20130101; B01L 2300/0806
20130101; B01L 2400/0409 20130101; B01J 2219/00722 20130101; B01J
2219/00702 20130101; B01J 2219/00605 20130101; B01L 3/5025
20130101; B01L 3/5027 20130101; B01J 2219/00596 20130101; B01J
2219/00659 20130101; G01N 21/07 20130101; B01L 2300/021 20130101;
B01J 2219/00675 20130101; B01L 2300/0636 20130101; B01L 3/502753
20130101; B82Y 30/00 20130101; B01J 2219/00689 20130101; B01J
2219/00536 20130101 |
Class at
Publication: |
422/102 ;
436/164; 422/082.09; 356/246; 435/006; 435/287.2; 435/288.5;
435/288.7 |
International
Class: |
G01N 21/00 20060101
G01N021/00; C12M 1/34 20060101 C12M001/34; B32B 27/12 20060101
B32B027/12 |
Claims
1. A biodisc, comprising: a light transmissive substrate; a first
reflective layer over the substrate having at least one opening for
receiving an investigational feature; a second reflective layer
configured at least over said opening; and a cap over the second
reflective layer.
2. The biodisc of claim 1, wherein the substrate is substantially
circular with a diameter and thickness substantially similar to
those of a compact disc.
3. The biodisc of claim 1, wherein the substrate and cap each
include polycarbonate.
4. The biodisc of claim 1, wherein the substrate has one or more
grooves formed therein.
5. The biodisc of claim 4, wherein the grooves are used to encode
data that can be read independently of the investigational
feature.
6. The biodisc of claim 1, wherein the first reflective layer has
encoded information being readable by an optical disc drive
system.
7. The biodisc of claim 1, further comprising an adhesive layer
between the substrate and the cap, the adhesive layer having at
least one cut-out portion to define a fluidic circuit, the fluidic
circuit including the viewing window.
8. The biodisc of claim 7, wherein the fluidic circuit is
substantially U-shaped.
9. The biodisc of claim 7, wherein the fluidic circuit includes at
least three chambers connected by passages there between.
10. The biodisc of claim 7, wherein the cap has a port for
providing access to the fluidics circuit.
11. The biodisc of claim 1, wherein a dye layer is between the
substrate and the first reflective layer, the dye layer allowing
information to be written to the disc.
12. The biodisc of claim 11, said substrate comprising grooves
formed therein and filled with dye.
13. The biodisc of claim 11, said substrate comprising grooves
formed therein and filled with said first reflective layer.
14. The biodisc of claim 1, wherein the first reflective layer is
selected from the group consisting of aluminum and gold.
15. The biodisc of claim 1, wherein the substrate has grooves and
the first reflective layer includes a metal layer extending into
the grooves
16. The biodisc of claim 1, wherein the bottom of the viewing
window is coplanar with the top of the substrate.
17. The biodisc of claim 1, wherein the bottom of the viewing
window extends into the substrate.
18. A biodisc comprising a substrate; a first reflective layer
comprising a reflective material formed on said substrate, said
first reflective layer comprising a first portion where there is no
reflective material; a cap disposed near said substrate, said cap
and said substrate substantially in parallel along a first
direction; a second reflective layer formed on a second portion of
said cap; and wherein said first portion and second portion are
aligned along a second direction perpendicular to the first
direction such that the second portion of the cap covers the first
portion.
19. The biodisc of claim 18, wherein said biodisc further comprises
a capture layer formed over said first portion, said capture layer
comprising a chamber between said first portion and said second
portion configured to receive a biological material for capturing a
reporter introduced into said chamber.
20. The biodisc of claim 18, where further said biodisc further
comprises a channel layer disposed between said substrate and said
cap, said channel layer comprising a patterned surface configured
to define one or more fluidic channels.
21. The biodisc of claim 18, wherein said biodisc further comprises
a reservoir positioned over a portion of said one or more fluidic
channels.
22. The biodisc of claim 21, wherein said biodisc further comprises
a vent connected to said reservoir.
23. A method of detecting an investigational feature using the disc
of claim 1, comprising: introducing a sample into said opening of
said first reflective layer; exposing said sample to reporters that
attach to the investigational feature; directing a beam of light
through an opening in said first reflective layer to the exposed
sample such that the beam reflects off said second reflective
layer; detecting a portion of said light reflected from said second
reflective layer; and analyzing said detected light to determine
the presence of reporters indicating the presence of the
investigational feature.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 09/999,274, filed on Nov. 15, 2001, which claims the benefit of
U.S. Provisional Application No. 60/249,391, filed on Nov. 16,
2000, and U.S. Provisional Application No. 60/275,705, filed on
Dec. 22, 2000, each of which are hereby expressly incorporated by
reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] As shown in U.S. Pat. No. 6,030,581, an optical disc can be
used to perform assays on biological or chemical samples. A sample
can be provided in an opening and then moved by centrifugal force
from one chamber or area to another chamber or area until it
reaches an assay region where the sample (or a characteristic of
the sample) can be observed. As shown in U.S. Pat. No. 5,892,577,
which also is incorporated herein by reference, a beam can be
scanned over a rotating disc. Radiation reflected from and/or
transmitted through the disc can be detected by a detector and used
to read encoded information and/or detect assays.
SUMMARY OF THE INVENTION
[0003] The embodiments of the present invention allow reflected
light to be used both to read operational data and to detect a
biological or chemical investigational feature and/or a
characteristic thereof. One embodiment includes a biodisc with a
substrate, a reflective layer over the substrate for encoding
information, an opening in the reflective layer at a viewing window
where an investigational feature can be provided, and a second
reflective layer spaced from the first reflective layer and at
least over the viewing window such that light passing through the
substrate to the viewing window can be reflected by the second
reflective layer. The first reflective layer can be directly on the
substrate or separated by intermediate layers, such as a dye layer.
Over the second reflective layer, a cap portion can be
provided.
[0004] The disc can have different configurations for channels and
chambers for moving a sample, such as a generally U-shaped circuit
or a series of chambers. At the viewing window, the investigational
feature can be detected by one of a number of methods, including
colorimetry, fluorimetry, the use of reporters, such as beads, or
the use of other methods by which a sample, or a characteristic of
a sample, can be observed. The disc can be used for medical
diagnostics, such as detecting cholesterol or glucose levels, or
for blood typing, detection of antigens, or any other desired
biological or chemical interaction. The disc can also be used for
imaging small objects.
[0005] A biodisc and drive system as described herein can have one
or more of a number of different advantages, including an ability
to detect investigational features with reflected light, to read
encoded data in addition to investigational features, and the
ability to use the focusing of a standard disc reader at the
reflective layer where information is encoded. This means that with
the disc shown in the embodiments, a conventional optical drive may
be usable with few changes. Other features and advantages will
become apparent from the following detailed description, drawings,
and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective view of an optical biodisc and an
associated reading system according to an embodiment of the present
invention.
[0007] FIG. 2 is an exploded view of three structural layers of an
optical biodisc according to embodiments of the present
invention.
[0008] FIGS. 3-8 are cross-sectional views of a disc according to
embodiments of the present invention.
[0009] FIGS. 9A-9D are cross-sectional views of an optical biodisc
with investigational features being introduced and demonstrating a
method according to an embodiment of the present invention.
[0010] FIGS. 10 and 11 are cross-sectional views of FIGS. 9A and
9G, respectively.
[0011] FIG. 12 is a graphical representation of detection signals
of reporters according to an embodiment of the present
invention.
DETAILED DESCRIPTION
[0012] Optical biodiscs for assays according to the present
invention may have any suitable shape, diameter, or thickness, but
preferably are implemented on a round disc with a diameter,
thickness, and materials similar to those of a compact disc (CD), a
recordable CD (CD-R), a digital versatile disc (DVD), or one of a
number of other formats. Compact discs, DVDs, and other such discs
have encoded informational (operational) data, such as audio
information or software. A biodisc according to embodiments of the
present invention has investigational features, and preferably both
encoded operational data and investigative features. The
operational information can include data for performing,
controlling, and post-processing a test or assay on a biological or
chemical material. This operational information can include, for
example, information for controlling the rotation rate of the disc,
the direction of rotation of the disc, timing for rotation,
stopping and starting of the disc, delay periods, multiple rotation
steps, locations of samples, and control of the power of the light
source.
[0013] Investigational features can include any chemical or
biological material providing a test result. In one embodiment,
target sequences, such as capture DNA strands or antibodies, are
attached to a disc surface in a viewing window (also referred to as
a viewing window). In the DNA example, a reporter is attached to a
target DNA sequence, which is complementary to a capture DNA
sequence. In the presence of a target sequence, the complementary
capture DNA strand will hybridize with the target, thereby
attaching DNA target sequences to the disc surface. In a subsequent
wash step, unbound reporters are removed. A beam of light focused
on the viewing window will determine the presence, or lack thereof,
of a target sequence. Such a system is described in more detail in
U.S. Provisional Application Ser. No. 60/257,705, filed Dec. 12,
2000, which is expressly incorporated by reference.
[0014] Other techniques for observing a sample or a characteristic
of a sample include colorimetry and fluorimetry. In the case of
colorimetry, a sample is provided in a viewing window, and the beam
of light is directed to the sample. From the amount of light that
is detected, information about the sample is derived.
[0015] An optical biodisc may generally be reflective,
transmissive, and/or have some combination of reflective and
transmissive portions. In the case of a reflective disc or in a
reflective portion, an incident light beam may be focused onto a
reflective surface of the disc, reflected by the reflective
surface, and returned through optical elements to a detector as it
would be in a conventional informational disc. In a transmissive
disc or transmissive portion of a disc, light passes through the
disc to a detector on the other side of the disc from the light
source. The transmissive portions could be partially reflective. A
transmissive disc is described in more detail in U.S. Provisional
Application Ser. Nos. 60/255,233, filed Dec. 12, 2000; 60/294,051,
filed May 29, 2001; 60/306,266, filed Jul. 18, 2001; 60/306,599,
filed Jul. 19, 2001; and 60/291,233, filed May 16, 2001, each of
which is incorporated herein by reference.
[0016] The embodiments of the present invention relate mainly to
reflective biodiscs which provide both operational and
investigative features, but the disc could include transmissive
portions as well.
[0017] FIG. 1 shows an optical disc 100 and disc drive system 200.
This disc drive system may be a conventional reader for CD, CD-R,
DVD, or other known comparable format with modifications to
software and minimal or no modifications to hardware, a modified
version of a conventional disc drive, or a distinct dedicated disc
drive device oriented to detecting investigational features. The
basic components of such a disc drive system are a light system for
providing light, a motor for rotating the disc, and a detection
system for detecting light.
[0018] A light source 202 provides light to optical components 212
to produce an incident light beam 204, which may be collimated or
non-collimated. In the case of a reflective portion of disc 100,
incident light beam 204 is reflected off disc 100 to produce a
return beam 206. Return beam 206 passes through optical components
212, and then to a detector 210. This detector can be a
conventional optical disc drive detector or a modified
detector.
[0019] Optical components 212 can include a lens, a beam splitter,
and a quarter wave plate that changes the polarization of the light
beam so that the beam splitter directs a reflected beam through the
lens to focus the reflected beam onto the detector. These are
conventional components in optical disc drives. An astigmatic
element, such as a cylindrical lens, may be provided between the
beam splitter and detector to introduce astigmatism in the
reflected light beam.
[0020] Data from detector 210 is provided to a computer 236,
including a processor 220 and an analyzer 222, and then to a
monitor 224 to display an image or results. This computer 236 can
represent a desktop computer, programmable logic, or some other
processing device, and also can include a connection (such as over
the Internet) to other processing and/or storage devices. A drive
motor 226 and a controller 228, which can be connected to computer
236, are provided for controlling the rotation of disc 100. Thus if
encoded operational data on disc 100 indicates that disc 100 is to
be rotated at a certain rate, computer 236 can direct controller
228 to drive motor 226 at that rate. Computer 236 and controller
228 can be on the same computer.
[0021] The disc can have a physical mark referred to as a trigger
mark 120. A hardware trigger sensor 218 is used to detect trigger
mark 120. Trigger sensor 218 provides a signal to computer 236 that
controls the collection and/or use of detected data by computer
236. In one embodiment, computer 236 only stores and analyzes data
relating to investigational features when trigger sensor 218
detects trigger mark 120. In this case, data regarding
investigational features is collected and analyzed when the trigger
is detected. The trigger is preferably aligned radially with
viewing windows. Trigger sensor 218 and trigger mark 120 can be
located under disc 100 and on the bottom side of disc 100,
respectively.
[0022] With a transmissive disc, there would also be a top detector
on the other side of the disc from the light source. Transmissive
disc detection is shown, for example, in U.S. Provisional
Application Ser. Nos. 60/270,095, filed Feb. 20, 2001; 60/292,108,
filed May 18, 2001; 60/292,110, filed May 18, 2001; 60/313,917,
filed Aug. 21, 2001; and in Gordon, U.S. Pat. No. 5,892,577, filed
Apr. 6, 1999, each of which is incorporated herein, by
reference.
[0023] Disc drive system 200 is thus employed to rotate disc 100,
read and process any encoded operational information stored on the
disc, and detect chemical, biological, or biochemical
investigational features in an assay region of the disc.
Optionally, in a system such as a CD-R, disc drive system 200 can
be used to write information to disc 100 either before or after the
material in the assay zone is analyzed by the read beam of the
drive.
[0024] FIG. 2 shows three layers of an example of an embodiment of
a reflective biodisc 100. The top layer, a cap 102, has inlet ports
110 for receiving samples, vent ports 112, and reflective layer
regions 148, which are on the underside of cap 102. Cap 102 may be
formed primarily from polycarbonate (e.g., about 1.2 mm thick).
Reflective layer regions 148 are preferably made from a metal, such
as aluminum or gold, with a sufficient thickness to be primarily or
exclusively reflective.
[0025] A channel layer 104, also referred to as an adhesive layer,
has fluidic circuits 128 formed therein preferably by stamping or
cutting desired shapes from the layer. The channel layer can be
over a capture layer where an investigational feature can bind.
Each fluidic circuit 128 can have a flow channel 130 and a return
channel 132. A fluidic circuit can include other microfluidic
channels and chambers, such as preparatory regions and a waste
region, as shown, for example, in the incorporated U.S. Pat. No.
6,030,581.
[0026] Substrate 106 is made up primarily of a layer of
polycarbonate, and has a reflective layer deposited on the top of
the polycarbonate layer. Viewing windows 140 are openings in the
reflective layer that may be formed by removing portions of the
reflective layer in any desired shape, or by masking viewing
windows 140 before applying the reflective layer. One viewing
window or a plurality of such windows can be oriented along one or
more radii from the center of the disc. The reflective layer on
substrate 106 is preferably formed from a metal, such as aluminum
or gold, and can be configured with the rest of substrate 106 to
encode operational information that is read with incident
light.
[0027] In operation, samples are provided through inlet ports 110.
When rotated, the sample moves outwardly from inlet ports 110 along
a fluidic circuit 128. Through one of a number of biological or
chemical reactions or processes, detectable investigational
features may then be present in viewing windows 140.
[0028] The disc may be designed so that investigational features
are captured to be in the focal plane coplanar with the reflective
layer that has encoded information. This reflective layer is where
an incident beam is typically focused conventionally through
optical components and the optical properties of the substrate;
alternatively, investigational features may be captured at a
location in front of or at the focal plane, i.e., farther from the
light source. The former configuration is referred to as a
"proximal" type disc (see FIG. 4), and the latter a "distal" type
disc (see FIG. 3).
[0029] Trigger marks 120 may be included on the surface of the
reflective layer, and may include a clear window in all three
layers of the biodisc, an opaque area, or a reflective or
semi-reflective area encoded with information. The use of the
trigger marks is described in conjunction with FIG. 1.
[0030] Substrate layer 106 may be impressed with a spiral track
that starts at an innermost readable portion of the disc and then
spirals out to an outermost readable portion of the disc. In a
non-recordable disc such as a CD, this track is made up of a series
of embossed pits with varying length, each typically having a depth
of approximately one-quarter the wavelength of the light that is
used to read the disc. The varying lengths and spacing between the
pits encode the operational data. The spiral groove of a recordable
CD-R disc has a detectable dye rather than pits.
[0031] Numerous designs and configurations of an optical pickup and
associated electronics may be used in the context of the
embodiments of the present invention. Further details and
alternative designs for compact discs and readers are described in
Compact Disc Technology, by Nakajima and Ogawa, IOS Press, Inc.
(1992); The Compact Disc Handbook, Digital Audio and Compact Disc
Technology, by Baert et al. (eds.), Books Britain (1996) and CD-Rom
Professional's CD-Recordable Handbook: The Complete Guide to
Practical Desktop CD, Starrett et al. (eds.), ISBN: 0910965188
(1996); all of which are incorporated herein in their entirety by
reference.
[0032] FIGS. 3 and 4 are cross-sectional views of an embodiment of
a reflective biodisc, similar to a CD-R disc, shown with
alternative depths for a viewing window 140 where an
investigational feature 125 could be. Investigational feature 125
may be suspended with a capture layer at the top or bottom of the
viewing window.
[0033] In FIG. 3, viewing window 140 is covered by a cap layer with
lacquer 102 (e.g., about 0.5 microns) and a reflective layer 148,
e.g., of gold or aluminum. Viewing window 140 is etched into a
layer of lacquer 162, a reflective coating layer 164, a layer of
dye 166, and a portion of substrate 168. In this embodiment,
viewing window 140 has a depth d greater than the sum of the depths
of layers 162, 164 and 166.
[0034] FIG. 4 is a cross-sectional view of a biodisc with a viewing
window 140 of depth d' that is equal to the sum of the depth of the
layers 162, 164, and 166 and does not cut into the layer of
substrate 172. This configuration provides an investigational
feature at the focal plane. Viewing window 140 is light
transmissive and, other than the investigational feature, can have
air, transmissive plastic, or a solution.
[0035] The layer of substrate 168 in FIGS. 3 and 4 includes a
series of grooves 170. Grooves 170 are in the form of a spiral
extending from near the center of the disc toward the outer edge
and are implemented so that an interrogation beam may track along
the spiral grooves 170 on the disc. This type of groove 170 is
known as a "wobble groove." Grooves 170 are formed by a bottom
portion having undulating or wavy side walls. A raised or elevated
portion separates adjacent grooves 170 in the spiral. Dye layer 166
applied on the grooves 170 in this embodiment is, as illustrated,
conformal in nature. At the viewing window in FIG. 4, layers 162,
164, and 166 are removed, as is dye 166 from grooves 170.
[0036] The path of an incident beam 152 is directed toward disc 100
from the light source. Incident beam 152 is focused on a point in a
focal plane coplanar with reflective layer 148 and continues
upwardly traversing through viewing window 140 to eventually fall
incident onto reflective surface 148. At this point, incident beam
152 is reflected back and thereby forms a return beam 154. Without
reflective layer 148 being added, the viewing window would be
transmissive. This model applies for the behavior of the light
beams for FIG. 4 through FIG. 8. The wavelength of the incident
beam can be, for example, 540 nm, 640 nm, or 780 nm for different
types of reading (and recording) formats.
[0037] FIGS. 5, 6, and 7 are cross-sectional views of a biodisc
with various embodiments of fluidic channels that have other
chambers, such as input preparation and waste chambers as shown,
for example, in the incorporated U.S. Pat. No. 6,030,581.
[0038] In FIG. 5, a fluidic channel 178 formed in substrate 168 has
reservoirs 132, 134, and 136, and a waste chamber 138. Reservoirs
132, 134, and 136 are connected to viewing window 140 by capillary
channel 142. Waste chamber 138 is also connected to viewing window
140 by vent 144. Viewing window 140, which is generally similar to
that shown in FIG. 3, is covered by a cap layer of lacquer 102 and
a reflective layer 148.
[0039] A sample can thus be provided to reservoir 132, provided
through reservoirs 134 and 136 to capillary channel 142 to viewing
window 140. The movement from reservoir 132 to viewing window 140
can be all at once, or in a series of stages governed by physical
resistance and different speeds of rotation--in other words,
rotation at a first rotation rate moves the sample from reservoir
132 to 134, rotation at a second rotation rate moves the sample
from reservoir 134 to 136, and then rotation at a third rotation
rate moves the sample from reservoir 136 to viewing window 140.
Delays for heating, incubating, or some other purpose can be
provided between steps.
[0040] FIGS. 6 and 7 show embodiments of a biodisc in which fluidic
circuits are located primarily in cap 190 and above the substrate
168 and reflective layer 164. In FIG. 6, chambers 202, 204 and 206
are input reservoirs with vents 210, 212, and 214. Waste chamber
208 has a vent 216. In this embodiment, the biodisc does not have a
layer of lacquer 162 over reflective layer 164. Instead, a layer of
adhesive 182 covers reflective layer 164.
[0041] Viewing window 140 is created by removing a portion of
reflective layer 164. A reflective layer 148 is at the top of
viewing window 140. FIG. 6 does not show a dye layer, and thus
could represent, for example, a CD rather than CD-R.
[0042] FIG. 7 shows a cross-sectional view of an embodiment similar
to that of FIG. 6, with grooves 170 etched into substrate 168.
Reflective layer 164 is applied on substrate 168. Unlike some other
embodiments in which dye is provided in grooves 170, the grooves
170 in this embodiment have the reflective layer material, such as
gold or aluminum or any other suitable reflective material. Without
a dye layer or an appropriate substitute, however, the drive cannot
write data back to the disc.
[0043] FIG. 8 is a cross-sectional view of a biodisc with only a
reflective layer 184. Substrate 168 of the biodisc has tracking
grooves 170 and a layer of conforming reflective material 184 on
top. This embodiment does not include a lacquer layer 162 and a dye
layer 166. Viewing window 140, which is created by removing a
portion of reflective layer 164, is covered by a cap 102 of lacquer
and a reflective layer 148.
[0044] FIGS. 9A-9O illustrate a method for detecting or determining
the presence of target DNA in a sample in conjunction with an
optical biodisc of the type described herein. In FIG. 9A, a pipette
230 is loaded with a test sample that has reporters 240 with target
DNA 242. The disc has a substrate 250 and a reflective layer 252
over substrate 250. Reflective layer 252 is selectively removed (or
selectively deposited initially) to have gaps where there are
viewing windows 234. A capture layer 254 is over the substrate in
the viewing windows 234, and may be over the entire reflective
layer 252 as well. Capture DNA strands 244 are anchored to the
capture layer in windows 234.
[0045] The test sample is injected or deposited into flow channel
141 through an inlet port 232. As flow channel 141 is further
filled with test sample, reporters 240 with DNA sequences 242 flow
in flow channel 141 as illustrated in FIG. 9B. When target DNA 242
of a specific sequence is present in the test sample, target DNA
242 hybridizes with the capture DNA 244, as shown in FIGS. 9C and
9D.
[0046] In this manner, reporters 240 are retained within the
viewing windows 234. Hybridization may be further facilitated by
rotating disc 100 so that reporters 240 slowly move or tumble down
flow channel 141. Slow movement allows ample time for additional
hybridization. After hybridization, the disc may be rotated further
to clear the viewing windows 234 of unattached reporters 240.
[0047] Interrogation beam 152 may then be scanned through viewing
windows 234 to determine the presence of reporters 240 as
illustrated in FIG. 9D. In the event no target DNA 242 is present,
all the reporters 240 are spun down flow channel 141 when disc 100
is rotated. In this case, when interrogation beam 152 is directed
into viewing windows 234, a negative reading will thereby result
indicating that no target DNA 242 was present in the sample.
[0048] FIGS. 10 and 11 are cross-sectional views of FIGS. 9A and
9C, respectively. In FIG. 9A, capture DNA 244 is attached to the
capture layer 254 within target window 234. When complementary
target DNA 242 and reporter 240 are injected into viewing window
140, target DNA 242 and capture DNA 244 hybridize. Interrogation
beam 152 then detects for reporters 240 after unattached reporters
have been washed away.
[0049] FIG. 12 shows graphically a method for detecting reporters.
In FIG. 12, a viewing window is shown with reporters 302, 304, and
306. These reporters could be beads, in the case where the binding
is for DNA, or cells, in the case where the detection is of
antigens on cells. The viewing window is shown with four tracks
310, 312, 314, and 316 of the disc. There could be many more
tracks, and the tracks that are shown may actually be spaced apart
with other track between them; e.g., the tracks shown here could be
every fourth track. The spacing is preferably selected based on the
size of the reporter being detected, such that the spacing between
tracks that are read is about the size of a reporter so as to
detect each reporter once. Around the viewing window is a
reflective layer 320, which may include encoded operational
information
[0050] As the light beam moves along the tracks, the amount of
reflected light is high outside of the viewing window. Within the
viewing window, where the reflective layer under the cap is spaced
from the focal point, the amount of reflected light declines.
Within the viewing window, more light is reflected when the light
beam reflects off the reporter. The analysis software thus looks
for a drop--and then increase in the amount of reflected light to
detect the bounds of the viewing window. Within the viewing window,
the analysis software looks for peaks that exceed a threshold and
counts these peaks. The light then moves to the next track to be
used, which may be several tracks away from the previously read
track. Such a reading system is shown, for example, in U.S.
Provisional Application Ser. No. 60/270,095, filed Feb. 20, 2001,
which is expressly incorporated herein by reference.
[0051] Other detection methods may be used. The counting can be
performed in hardware with edge detection circuitry. Other hardware
and software methods can be used, including imaging and using image
recognition software to detect individual reporters. Other
detection methods may be more oriented to a yes/no decision. The
boundary of the window can be determined from encoded information
in the reflective layer near the window.
[0052] Having described several embodiments of the present
invention, it should be apparent that modifications can be made
without departing from the scope of the invention as defined by the
appended claims. For example, the testing can be used for medical
diagnostics, biological agent detection (including biological
warfare), environmental testing, and forensic DNA analysis. A
CD-type system can image microstructures, detect and count cells,
detect microbeads (e.g., 1-6 microns) used in DNA and
immuno-assays, detect colorimetric substrates used in enzymatic
assays, and detect new or reported nanogold and nanocarbon. Assay
techniques include Ab-Ag reaction, hybridization, enzyme cascade,
chelation, binding to surface markers, and imaging by cell
identification and agglutination. The references to physical
relationship, such as one layer being "over" another, or light
being provided to the "bottom" of the disc, are meant as terms of
reference, but are not meant to literally be "over" necessarily;
rather, the light could be directed from above with the structure
upside down, or the disc could be on its side.
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