U.S. patent application number 13/911970 was filed with the patent office on 2013-12-12 for sensor for detection of a target of interest.
The applicant listed for this patent is National Taiwan University. Invention is credited to Luan-Yin CHANG, Si-Chen LEE, Shiming LIN.
Application Number | 20130330814 13/911970 |
Document ID | / |
Family ID | 49715562 |
Filed Date | 2013-12-12 |
United States Patent
Application |
20130330814 |
Kind Code |
A1 |
LIN; Shiming ; et
al. |
December 12, 2013 |
SENSOR FOR DETECTION OF A TARGET OF INTEREST
Abstract
A sensor comprises a light source that emits light, a light
receiver for receiving light, a sampling unit for binding the
target of interest disposed between the light source and the light
receiver, a light selecting unit for allowing light of a
predetermined wavelength be received by the light receiver, and a
detector configured to generate an electrical signal, and the
magnitude of which reflects the amount of light that is received by
the light receiver. The sampling unit comprises a substrate, a
material disposed on the substrate, and a probe disposed on the
material and configured to bind to the target of interest. The
sampling unit is configured such that the probe is in the path of
the light emitted by the light source.
Inventors: |
LIN; Shiming; (Taipei,
TW) ; LEE; Si-Chen; (Taipei, TW) ; CHANG;
Luan-Yin; (Taipei, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
National Taiwan University |
Taipei |
|
TW |
|
|
Family ID: |
49715562 |
Appl. No.: |
13/911970 |
Filed: |
June 6, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61656354 |
Jun 6, 2012 |
|
|
|
Current U.S.
Class: |
435/287.2 ;
422/69; 435/288.7 |
Current CPC
Class: |
G01N 33/54373 20130101;
G01N 21/03 20130101; G01N 33/56983 20130101; G01N 2021/0325
20130101; G01N 21/272 20130101; G01N 21/82 20130101; G01N 21/59
20130101 |
Class at
Publication: |
435/287.2 ;
435/288.7; 422/69 |
International
Class: |
G01N 33/569 20060101
G01N033/569 |
Claims
1. A sensor for detecting a target of interest, comprising: a light
source; a light receiver; a sampling unit for binding the target of
interest disposed between the light source and the light receiver,
the sampling unit comprises: a substrate; a material disposed on
the substrate; and a probe disposed on the material and configured
to bind to the target of interest, wherein the sampling unit is
configured such that the probe is in the path of light emitted by
the light source; a light selecting unit for allowing light of a
predetermined wavelength be received by the light receiver; and a
detector configured to generate an electrical signal, the magnitude
of which reflects the amount of light that is received by the light
receiver.
2. The sensor of claim 1, wherein the light receiver includes the
light selecting unit, which comprises: a slit for receiving the
light, a mirror, a grating, and a linear charge-coupled device,
wherein the mirror is configured to reflect the received light onto
the grating, the grating is configured to separate the received
light into a plurality of lights of different wavelengths and
transmit the plurality of lights to the linear charge-coupled
device, and wherein the detector comprises a photodetector circuit
for measuring the intensity of one of the plurality of light
received by the light receiver and generating the electrical signal
that is proportionate to the intensity of the one of the plurality
of light, the one of the plurality of light has the predetermined
wavelength.
3. The sensor of claim 1, wherein the light receiver comprises a
photodiode chip for receiving the light, and wherein the detector
comprises a photodetector circuit for measuring the intensity of
the light received by the light receiver and generating the
electrical signal that is proportionate to the intensity of the
light received by the light receiver.
4. The sensor of claim 3, wherein the light selecting unit
comprises a light filter disposed between the light source and the
sampling unit.
5. The sensor of claim 3, wherein the light selecting unit
comprises a light filter disposed between the sampling unit and the
light receiver.
6. The sensor of claim 1 further comprises an amplifier for
amplifying signals received by the light receiver.
7. The sensor of claim 1, wherein the light emitted from the light
source comprises a wavelength of about 200 nm to about 800 nm.
8. The sensor of claim 1, wherein the predetermined wavelength is
associated with the target of interest.
9. The sensor of claim 1, wherein the probe comprises DNA, RNA, a
protein, an antibody, an antibody fragment, an aptamer, an antigen,
or an epitope.
10. The sensor of claim 1, wherein the target of interest is a
biomolecule.
11. The sensor of claim 1, wherein the target comprises a virus, a
protein, a nucleic acid, a carbohydrate, a lipid, a hapten, or a
toxin.
12. The sensor of claim 1, wherein the probe binds to the target of
interest with an affinity of about 100 piconewtons to about 500
piconewtons.
13. The sensor of claim 1, wherein the material comprises a
metal.
14. The sensor of claim 1, wherein the material comprises a pattern
configured to scatter light emitted from the light source.
15. The sensor of claim 14, wherein the pattern is further
configured to facilitate the probe to scatter light emitted from
the light source when the target of interest is bound to the
probe.
16. The sensor of claim 14, wherein the pattern comprises a rod
array disposed on the substrate, and a rod of the rod array has a
length from 200 to 900 nm, a width from 200 to 900 nm and a height
from 15 to 1500 nm.
17. The sensor of claim 14, wherein the pattern comprises a film
with a substantially even thickness or an uneven thickness.
18. The sensor of claim 17, wherein the substantially even
thickness is in the range of 5 nm to 200 nm or the uneven thickness
varies from 0.5 nm to 30 nm.
19. The sensor of claim 1, wherein the light transmitted from the
light source is scattered by the probe and the target of interest
when the target is bound to the probe.
20. The sensor of claim 1, wherein the sampling unit is configured
for scattering of the light transmitted from the light source when
the target of interest is bound to the probe, wherein said light is
scattered in accordance with Rayleigh scattering, Mie scattering,
Brillouin scattering, Raman scattering, inelastic X-ray scattering
and Compton scattering.
21. A sensor for detecting a target of interest, comprising: a
light source that emits light of a predetermined wavelength; a
light receiver; a sampling unit for binding the target of interest
disposed between the light source and the light receiver, the
sampling unit comprises: a substrate; a material disposed on the
substrate; and a probe disposed on the material and configured to
bind to the target of interest, wherein the sampling unit is
configured such that the probe is in the path of the light emitted
by the light source; and a detector configured to generate an
electrical signal, the magnitude of which reflects the amount of
light that is received by the light receiver.
Description
BACKGROUND OF THE DISCLOSURE
[0001] A biological sensor is an analytical device for detecting a
target molecule by interaction of a biomolecule with the target
molecule. Compared to culturing or polymerase chain reaction (PCR),
a biological sensor can detect the existence of the target molecule
within a relatively short time period. Some biological sensors use
chromatographic immunoassay techniques. However, these
chromatographic immunoassay-based biological sensors have adoption
issues. For example, most chromatographic immunoassay-based
biological sensors detect antibodies which are generated by the
patients after a later stage of infection/disease.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] FIG. 1 shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule);
[0003] FIG. 2A shows an illustrative embodiment of a container of a
sensor for detecting a target of interest (e.g., a
biomolecule);
[0004] FIG. 2B shows another illustrative embodiment of a container
of a sensor for detecting a target of interest (e.g.,
biomolecule);
[0005] FIG. 2C shows yet another illustrative embodiment of a
container of a sensor for detecting a target of interest (e.g., a
biomolecule);
[0006] FIG. 3 shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule);
[0007] FIG. 4A shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule);
[0008] FIG. 4B shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule);
[0009] FIG. 4C shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule);
[0010] FIG. 4D shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule);
[0011] FIG. 5 shows an illustrative embodiment of a method for
making a sensor;
[0012] FIG. 6A is a chart illustrating the signal strength during
detection, by the sensor, of Enterovirus 71 in a 10% diluted sample
collected from an infected patient;
[0013] FIG. 6B is a chart illustrating the signal strength during
detection, by the sensor, of Enterovirus 71 in a control sample
collected from a healthy person;
[0014] FIG. 7A is a chart illustrating the signal strength during
detection, by the sensor, of Influenza A in a 10% diluted sample
collected from an infected patient;
[0015] FIG. 7B is a chart illustrating the signal strength during
detection, by the sensor, of Influenza A in a control sample
collected from a healthy person;
[0016] FIG. 8A is a chart illustrating the signal strength during
detection, by the sensor, of Influenza B in a 10% diluted sample
collected from an infected patient; and
[0017] FIG. 8B is a chart illustrating the signal strength during
detection, by the sensor, of Influenza B in a control sample
collected from a healthy person, all arranged in accordance with
embodiments of the disclosure.
SUMMARY
[0018] Some embodiments of the present disclosure may generally
relate to a sensor for detecting a target of interest. The sensor
may comprise a light source that emits light, a light receiver for
receiving light, a sampling unit for binding the target of interest
disposed between the light source and the light receiver, a light
selecting unit for allowing light of a predetermined wavelength be
received by the light receiver, and a detector configured to
generate an electrical signal. The magnitude of the electrical
signal reflects the amount of light that is received by the light
receiver. The sampling unit may comprise a substrate, a material
disposed on the substrate, and a probe disposed on the material and
configured to bind to the target of interest. Furthermore, the
sampling unit is configured such that the probe is in the path of
the light emitted by the light source.
[0019] Some additional embodiments of the present disclosure may
generally relate to a sensor for detecting a target of interest
that comprises a light source that emits light of a predetermined
wavelength, a light receiver for receiving light, a sampling unit
for binding the target of interest disposed between the light
source and the light receiver, and a detector configured to
generate an electrical signal. The magnitude of the electrical
signal reflects the amount of light that is received by the light
receiver. The sampling unit may comprise a substrate, a material
disposed on the substrate, and a probe disposed on the material and
configured to bind to the target of interest. The sampling unit is
configured such that the probe is in the path of the light emitted
by the light source.
[0020] The foregoing summary is illustrative only and is not
intended to be in any way limiting. In addition to the illustrative
aspects, embodiments, and features described above, further
aspects, embodiments, and features will become apparent by
reference to the drawings and the following detailed
description.
DETAILED DESCRIPTION
[0021] In the following detailed description, reference is made to
the accompanying drawings, which form a part hereof. In the
drawings, similar symbols typically identify similar components,
unless context dictates otherwise. The illustrative embodiments
described in the detailed description, drawings, and claims are not
meant to be limiting. Other embodiments may be utilized, and other
changes may be made, without departing from the spirit or scope of
the subject matter presented here. It will be readily understood
that the aspects of the present disclosure, as generally described
herein, and illustrated in the figures, can be arranged,
substituted, combined, and designed in a wide variety of different
configurations, all of which are explicitly contemplated and make
part of this disclosure.
[0022] In this disclosure, the term "probe" generally refers to a
substance (e.g., a biomolecule) that is capable of binding to a
target of interest (e.g., a biomolecule). For example, a probe may
have a binding affinity for the target of about 100 piconewtons
(pN) to about 500 pN. Nonlimiting examples of probes include
antibodies, antibody fragments that retain the ability to bind to
the target of interest, nucleic acids (e.g., DNA, RNA, aptamers),
antigens, and enzymes. In a sensor as described herein, a single
probe that recognizes a single target of interest, or two or more
probes that recognize a single target or multiple targets of
interest may be used.
[0023] The term "target" generally refers to any molecule that is
detectable with a sensor as described herein. A target may include,
but is not limited to, a biomolecule. Examples of targets that are
detectable in the sensors described herein include, but are not
limited to, biomolecules (for example, virus, proteins, nucleic
acids, carbohydrates, lipids), and other types of molecules (e.g.,
small molecules) such as, haptens, and toxins. In some embodiments,
the target is a biomolecule that is present in a bodily fluid
and/or tissue.
[0024] In some embodiments, a sensor for detecting a target of
interest (e.g., a biomolecule) includes a light source, a sampling
unit, and a light receiver having a light detector that generates
an electrical signal that is proportionate to the amount of light
received by the light receiver. The sampling unit may include a
container. At least one inner surface of the container includes
probes immobilized on a material that is disposed on the container
surface. The light source is configured to generate light that
passes through the container and eventually received by the light
detector. The light may be of a specific wavelength. Depending on
the target to be detected, the specific wavelength may be changed
accordingly. The specific wavelength may be determined by any
technical feasible approaches. In some embodiments, the specific
wavelength is determined by scanning the target with the visible
light spectrum or UV light spectrum. The maximum absorption
wavelength of the target in the visible light spectrum may be the
specific wavelength. For example, any of enterovirus 71, influenza
A virus, and influenza B virus has a maximum absorption at
approximately 560 nanometer (nm) wavelength in the visible light
spectrum and has a relatively greater absorption at about 280 nm
wavelength in the ultra-violet spectrum. Adenovirus has a maximum
absorption at about 340 nm wavelength in the visible light spectrum
and has a relatively greater absorption at about 280 nm wavelength
in the ultra-violet spectrum. If the target is present and bound to
the probes, light is scattered as it passes through the container,
amplifying the signal and resulting in a higher level of light
reaching the light receiver, and a larger magnitude electrical
signal generated by the light detector.
[0025] In some embodiments, the light source may generate visible
light or ultra-violet light. A light filter may be placed between
the light source and the container so that the light entering the
container has a specific wavelength. Alternatively, the light
filter may be placed between the container and the light detector
so that the light entering the light detector has a specific
wavelength. Alternatively, some optical elements (e.g., slit,
grating, mirror and a linear charge-coupled device) may be placed
between the container and the light detector to produce
monochromatic light having a specific wavelength from the visible
light that passed through the container, and allow the
monochromatic light to enter the light detector. Alternatively, the
light source may be a monochromatic light source.
[0026] In some embodiments, the container includes a substrate, a
material disposed on the substrate and one or more probe(s)
disposed on the material. The probe is immobilized on the material.
The probe may be a biological substance, for example, an antibody,
an antibody fragment, a nucleic acid, an aptamer, an antigen or an
enzyme, or any substance that is capable of binding to a target of
interest in a manner such that light scattering occurs when the
target is bound to the probe to a greater degree than when no
target is bound. The material is compatible with the probe and the
probe can be immobilized on the material. The material may be, for
example, a metal such as gold, silver, copper and nickel. The
substrate may be composed of any composition that is technically
feasible for the material to be disposed thereon, and that does not
interfere with detection of a target of interest as described
herein. Some examples of suitable substrates may include, without
limitation, glass, metal, silicon or polymers.
[0027] The material includes a pattern configured to enhance the
light scattering when the target is bound to the probe. In some
embodiments, the pattern itself is configured to scatter light when
the light travels through the pattern. In some embodiments, the
pattern may be a film coated on the substrate. In some other
embodiments, the coated film may be annealed. The annealing makes
the surface of the coated film becomes uneven. The uneven surface
may enhance the scattering of the light passing through the
container, and may provide an increase in the surface area
available for the deposition of the probe.
[0028] In some embodiments, the pattern may be a metal rod array
disposed on the substrate. The three dimensional property of the
metal rod array may also provide an increase in the surface area
available for the deposition of the probe. The size of a metal rod
in the metal rod array is associated with the specific wavelength
set forth above. In some exemplary embodiments, the length of any
metal rod is neither a multiple nor a factor of the specific
wavelength. The width of any metal rod is neither a multiple nor a
factor of the specific wavelength. The distance between two
adjacent rods is neither a multiple nor a factor of the specific
wavelength.
[0029] The probe is disposed or immobilized on the material through
one or more chemical bonds (e.g., covalent bond) with the material.
The probe may form a "lock and key" relationship with the target to
be detected by the sensor. For example, the probe may be DNA, RNA,
a protein, an antibody, an antibody fragment, an aptamer, an
antigen, or an enzyme. In some embodiments, the probe is an
antibody and the target is an antigen to which the antibody
binds.
[0030] A sample potentially including the target is introduced into
the sensor and then flows over the probe. If the target exists in
the sample, the amount of photons passing through the container
before the sample is introduced into the sensor may be different
than the amount of photons passing through the container after the
sample is introduced into the sensor because the target coupled
with the probe scatters photons. If the target does not exist in
the sample, the amount of photons passing through the container
remains substantially the same because there is no bound target to
scatter photons. In some embodiments, the amount of photons
absorbed by the sample is higher in the presence of bound target
than in the absence of the target, resulting in a difference in the
light signal detected when the target is present and the light
signal detected when the target is absent.
[0031] In some embodiments, a method for making a sensor is
disclosed. The method includes providing a material which includes
a pattern configured to scatter light or enhance a light scattering
associated with the target of interest, and increase the surface
area available for binding with the probes, disposing the material
on a substrate and disposing the probes configured to interact with
the target of interest on the material.
[0032] In some embodiments, the material is a film. The substrate
may be cleaned before the material is disposed on the substrate. In
some embodiments, before the material is disposed on the substrate,
an adhesion layer is disposed on the substrate first. Then the
material is disposed on the adhesion layer. The adhesion layer may
be chromium.
[0033] In some other embodiments, the material is an annealed film
which has an uneven surface pattern. The material may be annealed
at a temperature from about 300 degrees Celsius (.degree. C.) to
about 500.degree. C. after the material is disposed on the adhesion
layer.
[0034] In some other embodiments, the material includes a rod array
pattern. A photoresist is coated on the substrate and a
photolithography process is performed to form the rod array. The
size of each rod in the rod array and the distance between two
adjacent rods are associated with at least one of the specific
wavelength, the size of the probe, and the size of the target of
interest.
[0035] In some embodiments, a method for detecting a target of
interest with a sensor described herein is disclosed. The sensor
includes a light source, a container and a light detector. The
container includes a substrate, a material disposed on the
substrate and a probe configured to interact with the target of
interest. The probe is disposed and immobilized on the material.
The method includes transmitting light from the light source
through the container and obtaining a first signal based on the
light received by a light detector of the sensor.
[0036] The method also includes placing a sample that potentially
includes the target of interest in the sensor and obtaining a
second signal based on the light received by the light detector
after the sample is placed in the container. The method further
includes comparing the first signal and the second signal and
determining whether the target exists in the sample based on the
comparison.
[0037] FIG. 1 is an illustrative embodiment of a sensor 100 for
detecting a target of interest. The sensor 100 includes a sampling
unit. The sampling unit includes a container 101. The container
forms an apparatus for binding a target of interest, and includes a
material 111 disposed on a substrate 110 (e.g., one or more walls
of the container) and probes 113 that are capable of binding to the
target disposed on the material. A light 112 is transmitted from a
light source of the sensor 100 to a light receiver of the sensor
100 through the container 101. The probes 113 disposed on the
material 111 are configured in the path of the light emitted by the
light source. The probes 113 are configured such that light passing
through the apparatus is scattered when the target of interest is
bound to the probes 113.
[0038] A solution that does not contain the target, such as a
buffer solution, is introduced into the container 101. The light
112 is configured to pass through the container 101 in a first time
slot and is received by the light receiver. The light receiver
further includes a light detector, such as a photodiode detector,
configured to generate a first electronic signal based on the
amount of the light 112 that is received by the light receiver in
the first time slot. The light receiver further includes a
processor for processing the first electronic signal.
[0039] A sample 900 potentially including the target of interest
901 is then introduced into the container 101. A predetermined
amount of time is allowed to lapse so that if the target of
interest 901 exists in the sample 900, the target of interest 901
may bind to the probes 113 on the material 111. After the
predetermined period of time has lapsed, introduced sample 900 in
the container 101, including impurities 902, is removed from the
container 101 by a draining pump 400 through a first hole 107, a
passage 109 and a second hole 108, without breaking the bond
between the target of interest 901 and the probes 113.
Subsequently, the container 101 is rinsed with a buffer solution
for a predetermined number of times. For example, fresh buffer
solution may be repeatedly injected into and pumped out from the
container 101 several times.
[0040] Light scattering that occurs when target molecules are bound
to the probes 113 on the apparatus will be detected, indicating
presence of the target 901 in the sample 900. The light 112 is
configured to pass through the container 101 in a second time slot
and is received by the light receiver. The photodiode detector of
the light receiver is configured to generate a second electronic
signal based on the amount of the light that is received by the
light receiver in the second time slot. The processor of the light
receiver is configured to further process the second electronic
signal. If the strength of the second signal differs significantly
from the first signal, the processor determines that the target of
interest exists in the sample. For example, if the second signal is
significantly stronger than the first signal, the processor
determines that the target of interest is present in the
sample.
[0041] FIG. 2A shows an illustrative embodiment of an apparatus for
binding a target of interest. The apparatus 200 includes a
substrate 201, a film 203 disposed on the substrate and a probe 205
disposed on the film 203. The thickness of the film 203 may be, for
example, a substantially even thickness of about 5 nm to about 200
nm. A first surface 2051 of the probe 205 is disposed on the
material 203. A second surface 2053 of the probe 205 having a
binding affinity for the target 207 is configured such that it is
available to couple with the target 207 when the target 207 is
present. The probes 205 are configured on the film 203 such that
light 210 (shown as arrow in FIG. 2A) is scattered when the target
207 binds to the second surface 2053 of probes 205.
[0042] FIG. 2B shows an illustrative embodiment of an apparatus for
binding a target of interest. The apparatus 200 includes a
substrate 201, a rod array 203 disposed on the substrate and a
probe 205 disposed on the rod array 203. The width and the length
of any rod in the rod array 203 and the distance between two
adjacent rods are associated with at least one of the wavelength of
light transmitted from a light source of the sensor, the size of
the probe 205 and the target of interest 207. The wavelength is
specific to a target of interest 207. The distance between two
adjacent rods is also associated with such wavelength. In some
embodiments, the width, the length and the distance are all neither
a multiple of the wavelength, nor a factor of the wavelength. In
some embodiments, the rod of the rod array 203 may have a length
from 200 to 900 nm, a width from 200 to 900 nm and a height from 15
to 1500 nm. The distance between each rod in the rod array may be
from 200 to 900 nm. In some embodiments, the rod of the rod array
may have a length of approximately 500 nm, a width of approximately
500 nm and a height of about 100 nm, and the distance between each
rod may be approximately 500 nm. A first surface 2051 of the probe
205 is disposed on the rod array 203. A second surface 2053 of the
probe 205 having a binding affinity for the target 207 is
configured such that it is available to couple with the target 207
when the target 207 is present. The probes 205 are configured on
the rod array 203 such that light 210 (shown as arrow in FIG. 2B)
is scattered when the target 207 binds to the second surface 2053
of probes 205.
[0043] FIG. 2C shows an illustrative embodiment of an apparatus for
binding a target of interest. The apparatus 200 includes a
substrate 201, a film 203 disposed on the substrate and a probe 205
disposed on the film 203. The film 203 has an uneven thickness. In
some embodiments, the film may be first coated on the substrate 201
and then annealed to form the uneven thickness. In some
embodiments, the thickness of the film 203 may vary from
approximately 0.5 nm to approximately 30 nm. A first surface 2051
of the probe 205 is disposed on the film 203. A second surface 2053
of the probe 205 having a binding affinity for the target 207 is
configured such that it is available to couple with the target 207
when the target 207 is present. The probes 205 are configured on
the material 203 such that light 210 (shown as arrow in FIG. 2C) is
scattered when the target 207 binds to the second surface 2053 of
probes 205.
[0044] FIG. 3 shows an illustrative embodiment of an apparatus 300
for providing and detecting light passing through an apparatus 200
for detecting a target of interest. The apparatus 300 includes a
light source 310 and a light receiving unit 320. The apparatus 200
for detecting a target of interest is disposed between the light
source 310 and the light receiving unit 320.
[0045] The apparatus 200 for detecting a target of interest may
include a substrate 201, a film 203 disposed on the substrate and a
probe 205 disposed on the film 203. The configuration of the
substrate 201, the film 203 and the probe 205 in the apparatus 200
for detecting a target of interest may be the same or similar to
those in the apparatus 200 illustrated and described in reference
to FIGS. 2A, 2B and 2C.
[0046] Light 210 (shown as arrows in FIG. 3) from the light source
310 pass through the apparatus 200 for detecting a target of
interest. When the target 207 binds to the probe 205, the target
207 will absorb some light, and scatter some other light away from
the path of the incident light 210. The presence of the target 207
will cause a loss in light power falling on a first photodetector
unit 321, which is disposed optically in line with the path of the
incident light 210 for turbidimetric detection. Therefore, a first
signal may be obtained based on the light received by the first
photodetector unit 321 before a sample that potentially includes
the target of interest is placed in the apparatus 200 for detecting
a target of interest. For instance, the strength of the first
signal may be proportional to the intensity of the light received
by the first photodetector unit 321. Moreover, a second signal may
be obtained based on the light received by the first photodetector
unit 321 after the unbound materials in the sample have been
removed and replaced with a buffer solution. Furthermore, a
processor may compare the difference between the first signal and
the second signal, and determine whether or not the target exists
in the sample. If the strength of the second signal is
significantly less than strength of the first signal, the processor
may determine that the target exists in the sample.
[0047] In some embodiments, the light receiving unit 320 may
further comprise a second photodetector unit 322, which is disposed
at an angle relative to the path of the incident light 210 for
nephelometric detection. In some embodiments, the light receiving
unit 320 includes the second photodetector unit 322, but not the
first photodetector unit 310. The angle may be, for example, any
angle that is greater than 0 but less than or equal to 90, allowing
the second photodetector unit 322 to receive scattered light. Since
the target 207 attached to the probe 205 will scatter the incident
light 210, the intensity of the scattered radiation will increase
due to the presence of the target 207. Therefore, a first signal
may be obtained based on the light received by the second
photodetector unit 322 before a sample that potentially includes
the target of interest is placed in the apparatus 200 for detecting
a target of interest. Moreover, a second signal may be obtained
based on the light received by the second photodetector unit 322
after the unbound materials in the sample have been removed and
replaced with a buffer solution. Furthermore, a processor may
compare the difference between the first signal and the second
signal, and determine whether or not the target exists in the
sample. If the strength of second signal is significantly stronger
than strength of the first signal, the processor may determine that
the target exists in the sample.
[0048] In some embodiments, the light source may generate visible
light or ultra-violet light. A light filter may be placed between
the light source and the apparatus 200 for detecting a target of
interest so that the light entering the apparatus 200 for detecting
a target of interest has a specific wavelength. Alternatively, the
light filter may be placed between the apparatus 200 for detecting
a target of interest and the light detector so that the light
entering the light detector has a specific wavelength.
Alternatively, some optical elements (e.g., slit, grating, mirror
and a linear charge-coupled device) may be placed between the
apparatus 200 for detecting a target of interest and the light
detector to make the visible light (or ultra-violet light) passed
through the apparatus 200 for detecting a target of interest turn
to a monochromatic light with a specific wavelength before entering
the light detector. The light source may also be a monochromatic
light source.
[0049] FIG. 4A shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule). For
simplicity, a light receiving unit 320 comprising only one
photodetector unit is illustrated. One skilled in the art will
appreciate that the photodetector unit may be either one of the
first photodetector unit 310 and the second photodetector unit 320
illustrated in FIG. 3, and the light receiving unit 320 may
comprise additional photodetector units.
[0050] The light source 310 in FIG. 4A may emit visible light
(shown as arrows in FIG. 4A), and a light filter 308 for selecting
a light of a specific wavelength from the visible light may be
disposed between the light source 310 and the apparatus 200 for
detecting a target of interest. The light may be selected based on
the target of interest. For example, if the target of interest is
enterovirus 71, influenza A virus or influenza B virus, the light
filter 308 may be configured to select a light that has a 560 nm
wavelength, and if the target of interest is adenovirus, the light
filter 308 may be configured to select light that has a 340 nm
wavelength.
[0051] The light receiving unit 320 may comprise a photodiode chip
301 for receiving the light and a photodetector circuit 302 for
measuring the intensity of the selected light that passes through
the apparatus 200 for detecting a target of interest and generating
an electrical signal that is proportionate to the amount of light
received by the light receiving unit 320.
[0052] FIG. 4B shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule). The sensor
illustrated in FIG. 4B is the same as or similar to the sensor
illustrated in FIG. 4A, except the light filter 308 is disposed
between the apparatus 200 for detecting a target of interest and
the photodiode chip 301, instead of between the light source 310
and the apparatus 200 for detecting a target of interest.
Therefore, the light having the wavelength specific to the target
is selected after the light has passed through the apparatus 200
for detecting a target of interest.
[0053] FIG. 4C shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule). The sensor
illustrated in FIG. 4C is the same as or similar to the sensor
illustrated in FIG. 4A, except that the light filter 308 and
photodiode chip 301 are eliminated and the light receiving unit 320
in FIG. 4C comprises a slit 303, a mirror 304, a grating 305, and a
linear charge-coupled device (CCD) 306. The visible light that
passes through the apparatus 200 for detecting a target of interest
enters the slit 303. The grating 305 separates lights of different
wavelengths, which are then received by the linear CCD 306, and the
photodetector circuit 302 is configured to measure the intensity of
the light having the desired wavelength.
[0054] FIG. 4D shows an illustrative embodiment of a sensor for
detecting a target of interest (e.g., a biomolecule). The sensor
illustrated in FIG. 4D is the same as the sensor illustrated in
FIG. 4A, except that the light source 310 in FIG. 4D emits a
monochromatic light having a specific wavelength associated with
the target of interest. Therefore, the light filter 308 may be
eliminated in the example illustrated in FIG. 4D. The light
receiving unit 320 may further comprise an amplifier 307 for
amplifying signals received by the photodiode chip 301.
[0055] FIG. 5 shows a flow chart of an illustrative embodiment of a
method 500 for making an apparatus for binding a target of
interest. The method 500 includes steps 501, 503 and 505. In step
501, a material is provided. In step 503, the material is disposed
on a substrate. The material may be disposed on the substrate in a
pattern configured to increase the surface area available for
disposing probes, and to permit and/or enhance scattering light
emitted from a light source and traveling across the apparatus when
a target of interest is bound to a probe that is disposed on the
material. The pattern may be, for example, a film, a film with an
uneven thickness, or a rod array. In step 505, a probe that is
capable of binding to a target of interest is disposed on the
material. The probe is configured to interact with the target that
the sensor configured to detect. In some embodiments, before
disposing the probe on the material, the material may be cleaned
and pre-treated. For example, the material may be cleaned with an
acidic solution, a basic solution, and/or purified water. In some
embodiments, the material may be pre-treated with one or more
compounds. In one embodiment, the material may be pretreated with
one or more compound(s) that include(s) at least one functional
group compatible with the material. In another embodiment, the
material may be pretreated with one or more compound(s) that
include(s) at least one functional group compatible with the probe.
The functional group is configured to form a first stable bound
with the free electrons around the surface of the material and form
a second stable bound with the probe. Some example functional
groups include, but not limited to, thiol group and hydroxyl
group.
Example 1
Probe Immobilization
[0056] A glass container configured to contain a sample was placed
in a plastic holder and the glass container and the plastic holder
were then placed in pTricorder.RTM. sensor (Vsense Medtech. Co.,
Ltd., Taipei, Taiwan). Gold was disposed on an inner surface of the
container in the form of a film having an uneven thickness from
approximately 0.5 nm to approximately 30 nm. Before introducing
probes into the container, the gold film was cleaned with a 0.1 M
hydrochloric acid solution, purified water, 0.1 M sodium hydroxide,
and purified water, in sequence.
[0057] After cleaning, an aqueous solution containing 110 .mu.L of
cystamine (20 mM in phosphate buffered saline (PBS) solution at pH
7.2) was added into the container and incubated for 20 minutes at
room temperature to permit cystamine to bind to the gold on the
container wall. The remaining cystamine solution was then removed
from the container. An aqueous solution containing 110 .mu.L of
glutaraldehyde (2.5% in PBS solution at pH 7.2) was then added into
the container and incubated for 20 minutes at room temperature to
permit glutaraldehyde to bind to the cystamine.
[0058] After removing the remaining glutaraldehyde solution from
the container, an aqueous solution of 110 .mu.L of commercially
available anti-Enterovirus 71 monoclonal antibodies was added into
the container and incubated for 20 minutes at room temperature to
permit anti-Enterovirus 71 monoclonal antibodies to bind to the
glutaraldehyde crosslinker. Unbound anti-Enterovirus 71 monoclonal
antibody was then removed from the container by a draining pump of
the sensor through a hole at the bottom of the glass container. An
aqueous solution of 0.5M glycine was then added to the container to
react with residual unbound glutaraldehyde. Finally, glycine was
removed from and PBS was added to the container.
[Sample Detection]
[0059] The sensor further includes a visible light source and a
light detector for detection of Enterovirus 71. Visible light was
transmitted from the visible light source and passed through an
optical filter. The optical filter was configured to filter the
visible light and only the light having a 560 nm wavelength can
pass the optical filter. The light (i.e., having the wavelength of
560 nm) then passed through the glass container set forth above.
After passing through the glass container, the light was eventually
received by the light detector. FIG. 6A is a chart illustrating the
signal strength during detection of Enterovirus 71 in a 10% diluted
sample collected from an infected patient. The sample was collected
by a throat swab from the infected patient.
[0060] The sensor was turned on so that light transmitted from the
light source of the sensor passed through the container and over
the probes on the inner surface of the container. At this stage,
the container contained PBS as set forth above. The signal detected
with PBS (as shown at 601 in FIG. 6A) was used as a reference.
[0061] After about 1 minute, PBS was removed from the container and
the 10% Enterovirus 71 diluted sample was added to the container.
Data was collected for 10 minutes. Light detected from the
container is shown at 603 in FIG. 6A. After 10 minutes, the
Enterovirus 71 diluted sample was removed from the container.
[0062] PBS was added to rinse the container to remove
nonspecifically bound Enterovirus 71. The rinsing was repeated
several times. The rinsing caused various sharp peaks as shown at
605 in FIG. 6A. After rinsing, PBS was added to the container and
data was collected for 3 minutes to collect data for light detected
from the container (as shown at 607 in FIG. 6A). The difference
between the light signal detected at 607 and the signal detected at
601 indicated presence of Enterovirus 71 in the sample.
Comparative Example 1
[0063] FIG. 6B is a chart illustrating the signal strength during
detection of a control sample collected from a healthy person. The
detection approach was the same as the approach of the detection of
the 10% Enterovirus 71 diluted sample set forth above.
[0064] The sensor was turned on so that a light transmitted from a
light source of the sensor passed through the container and over
the probes on the inner surface of the container. At this stage,
the container contained PBS. The signal detected with PBS (as shown
at 611 in FIG. 6B) was used as a reference.
[0065] After about 1 minute, PBS was removed from the container and
the control sample was added to the container. Data was collected
for 10 minutes. Light detected from the container is shown at 613
in FIG. 6B. After 10 minutes, the control sample was removed from
the container.
[0066] PBS was added to rinse the container to remove
nonspecifically bound material. The rinsing was repeated several
times. The rinsing caused various sharp peaks as shown at 615 in
FIG. 6B. After rinsing, PBS was added to the container and data was
collected for 3 minutes to collect data for light detected from the
container (as shown at 617 in FIG. 6B). The similar signal strength
of 611 and 617 showed no existence of Enterovirus 71 in the control
sample.
Example 2
Probe Immobilization
[0067] A glass container configured to contain a sample was placed
in a plastic holder and the glass container and the plastic holder
were then placed in pTricorder.RTM. sensor (Vsense Medtech, Taipei,
Taiwan). Gold was disposed on an inner surface of the container in
the form of a film having an uneven thickness from about 0.5 nm to
about 30 nm. Before introducing probes into the container, the gold
film was cleaned with a 0.1M hydrochloric acid solution, purified
water, 0.1M sodium hydroxide, and purified water, in sequence.
[0068] After cleaning, an aqueous solution containing 110 .mu.L of
cystamine (20 mM in phosphate buffered saline (PBS) solution at pH
7.2) was added into the container and incubated for 20 minutes at
room temperature to permit cystamine to bind to the gold on the
container wall. The remaining cystamine solution was then removed
from the container. An aqueous solution containing 110 .mu.L of
glutaraldehyde (2.5% in PBS solution at pH 7.2) was then added into
the container and incubated for 20 minutes at room temperature to
permit glutaraldehyde to bind to the cystamine.
[0069] After removing the remaining glutaraldehyde solution from
the container, an aqueous solution of 110 .mu.L of commercially
available anti-Influenza A antibody (20 .mu.g/ml in PBS solution at
pH 7.2) was added into the container and incubated for 20 minutes
at room temperature to permit the anti-Influenza A antibody to bind
to the glutaraldehyde crosslinker. Unbound anti-Influenza A
antibody was then removed from the container by a draining pump of
the sensor through a hole at the bottom of the glass container. An
aqueous solution of 0.5M glycine was then added to the container to
react with residual unbound glutaraldehyde. Finally, glycine was
removed from and PBS was added to the container.
[Sample Detection]
[0070] The sensor further includes a visible light source and a
light detector for detection of Influenza A. Visible light was
transmitted from the visible light source and passed through an
optical filter. The optical filter was configured to filter the
visible light and only the light having a 560 nm wavelength can
pass the optical filter. The light (i.e., having the wavelength of
560 nm) then passed through the glass container set forth above.
After passing through the glass container, the light was eventually
received by the light detector. FIG. 7A is a chart illustrating the
signal strength during detection of Influenza A in a 10% diluted
sample collected from an infected patient. The sample was collected
by a throat swab from the infected patient's throat.
[0071] The sensor was turned on so that light transmitted from a
light source of the sensor passed through the container and over
the probes on the inner surface of the container. At this stage,
the container contained PBS as set forth above. The signal detected
with PBS (as shown at 701 in FIG. 7A) was used as a reference.
[0072] After about 1 minute, PBS was removed from the container and
the 10% Influenza A diluted sample was added to the container. Data
was collected for 10 minutes. Light detected from the container is
shown at 703 in FIG. 7A. After 10 minutes, the Influenza A diluted
sample was removed from the container.
[0073] PBS was added to rinse the container to remove
nonspecifically bound material. The rinsing was repeated several
times. The rinsing caused various sharp peaks as shown at 705 in
FIG. 7A. After rinsing, PBS was added to the container and data was
collected for 3 minutes to collect data for light detected from the
container (as shown at 707 in FIG. 7A). The difference between the
light signal detected at 707 and the signal detected at 701
indicated presence of Influenza A in the sample.
Comparative Example 2
[0074] FIG. 7B is a chart illustrating the signal strength during
detection of a control sample collected from a healthy person. The
detection approach was the same as the approach of the detection of
the Influenza A diluted sample set forth above.
[0075] The sensor was turned on so that a light transmitted from a
light source of the sensor passed through the container and over
the probes on the inner surface of the container. At this stage,
the container contained PBS. The signal detected with PBS (as shown
at 711 in FIG. 7B) was used as a reference.
[0076] After about 1 minute, PBS was removed from the container and
the control sample was added to the container. Data was collected
for 10 minutes. Light detected from the container is shown at 713
in FIG. 7B. After 10 minutes, the control sample was removed from
the container.
[0077] PBS was added to rinse the container to remove
nonspecifically bound material. The rinsing was repeated several
times. The rinsing caused various sharp peaks as shown at 715 in
FIG. 7B. After rinsing, PBS was added to the container and data was
collected for 3 minutes to collect data for light detected from the
container (as shown at 717 in FIG. 7B). The similar signal strength
of 711 and 717 showed no existence of Influenza A in the control
sample.
Example 3
Probe Immobilization
[0078] A glass container configured to contain a sample was placed
in a plastic holder and the glass container and the plastic holder
were then placed in pTricorder.RTM. sensor (Vsense Medtech Taipei,
Taiwan). Gold was disposed on an inner surface of the container in
the form of a film having an uneven thickness from about 0.5 nm to
about 30 nm. Before introducing probes into the container, the gold
film was cleaned with a 0.1 M hydrochloric acid solution, purified
water, 0.1 M sodium hydroxide, and purified water, in sequence.
[0079] After cleaning, an aqueous solution containing 110 .mu.L of
cystamine (20 mM in phosphate buffered saline (PBS) solution at pH
7.2) was added into the container and incubated for 20 minutes at
room temperature to permit cystamine to bind to the gold on the
container wall. The remaining cystamine solution was then removed
from the container. An aqueous solution containing 110 .mu.L of
glutaraldehyde (2.5% in PBS solution at pH 7.2) was then added into
the container and incubated for 20 minutes at room temperature to
permit glutaraldehyde to bind to the cystamine.
[0080] After removing the remaining glutaraldehyde solution from
the container, an aqueous solution of 110 .mu.L of commercially
available anti-Influenza B antibody (20 .mu.g/ml in PBS solution at
pH 7.2) was added into the container and incubated for 20 minutes
at room temperature to permit the anti-Influenza B antibody to bind
to the glutaraldehyde crosslinker. Unbound anti-Influenza B
antibody was then removed from the container by a draining pump of
the sensor through a hole at the bottom of the glass container. An
aqueous solution of 0.5M glycine was then added to the container to
react with residual unbound glutaraldehyde. Finally, glycine was
removed from and PBS was added to the container.
[Sample Detection]
[0081] The sensor further includes a visible light source and a
light detector for detection of Influenza B. Visible light was
transmitted from the visible light source and passed through an
optical filter. The optical filter was configured to filter the
visible light and only the light having a 560 nm wavelength can
pass the optical filter. The light (i.e., having the wavelength of
560 nm) then passed through the glass container set forth above.
After passing through the glass container, the light was eventually
received by the light detector. FIG. 8A is a chart illustrating the
signal strength during detection of Influenza B in a 10% diluted
sample collected from an infected patient. The sample was collected
by a throat swab from the infected patient's throat.
[0082] The sensor was turned on so that light transmitted from a
light source of the sensor passed through the container and over
the probes on the inner surface of the container. At this stage,
the container contained PBS as set forth above. The signal detected
with PBS (as shown at 801 in FIG. 8A) was used as a reference.
[0083] After about 1 minute, PBS was removed from the container and
the 10% Influenza B diluted sample was added to the container. Data
was collected for 10 minutes. Light detected from the container is
shown at 803 in FIG. 8A. After 10 minutes, the Influenza B diluted
sample was removed from the container.
[0084] PBS was added to rinse the container to remove
nonspecifically bound material. The rinsing was repeated several
times. The rinsing caused various sharp peaks as shown at 805 in
FIG. 8A. After rinsing, PBS was added to the container and data was
collected for 3 minutes to collect data for light detected from the
container (as shown at 807 in FIG. 8A). The difference between the
light signal detected at 807 and the signal detected at 801
indicated presence of Influenza B in the sample.
Comparative Example 3
[0085] FIG. 8B is a chart illustrating the signal strength during
detection of a control sample collected from a healthy person. The
detection approach was the same as the approach of the detection of
the Influenza B diluted sample set forth above.
[0086] The sensor was turned on so that a light transmitted from a
light source of the sensor passed through the container and over
the probes on the inner surface of the container. At this stage,
the container contained PBS. The signal detected with PBS (as shown
at 811 in FIG. 8B) was used as a reference.
[0087] After about 1 minute, PBS was removed from the container and
the control sample was added to the container. Data was collected
for 10 minutes. Light detected from the container is shown at 813
in FIG. 8B. After 10 minutes, the control sample was removed from
the container.
[0088] PBS was added to rinse the container to remove
nonspecifically bound material. The rinsing was repeated several
times. The rinsing caused various sharp peaks as shown at 815 in
FIG. 8B. After rinsing, PBS was added to the container and data was
collected for 3 minutes to collect data for light detected from the
container (as shown at 817 in FIG. 8B). The similar signal strength
of 811 and 817 showed no existence of Influenza B in the control
sample.
[0089] Although the foregoing invention has been described in some
detail by way of illustration and examples for purposes of clarity
of understanding, it will be apparent to those skilled in the art
that certain changes and modifications may be practiced without
departing from the spirit and scope of the invention. Therefore,
the description should not be construed as limiting the scope of
the invention.
[0090] All publications, patents, and patent applications cited
herein are hereby incorporated by reference in their entireties for
all purposes and to the same extent as if each individual
publication, patent, or patent application were specifically and
individually indicated to be so incorporated by reference.
* * * * *