U.S. patent application number 17/172078 was filed with the patent office on 2022-01-06 for method of detecting a substance.
This patent application is currently assigned to Purdue Research Foundation. The applicant listed for this patent is Purdue Research Foundation. Invention is credited to Nikhil Bajaj, George Tsu-Chih Chiu, Allison Kelly Murray, Eric A. Nauman, Jeffrey Frederick Rhoads, Mackenzie Tweardy, Michael Wadas.
Application Number | 20220003760 17/172078 |
Document ID | / |
Family ID | 1000005841739 |
Filed Date | 2022-01-06 |
United States Patent
Application |
20220003760 |
Kind Code |
A1 |
Rhoads; Jeffrey Frederick ;
et al. |
January 6, 2022 |
METHOD OF DETECTING A SUBSTANCE
Abstract
A method of detecting a substance, wherein the method includes
functionalizing a plurality of sensors, wherein the functionalizing
the plurality of sensors comprises depositing a first material
using a piezoelectrically actuated pipette system, wherein the
first material includes a polymer, a receptor, and a solvent,
wherein the solvent comprises dimethylformamide. The method further
includes evaporating a solution of the first material, wherein a
residue after the evaporation comprises a functionalized chemical.
Additionally, the method includes introducing a control material to
a first set of sensors of the plurality of sensors using the
piezoelectrically actuated pipette system. Further, the method
includes introducing a test material to a second set of sensors of
the plurality of sensors using the piezoelectrically actuated
pipette system, wherein the test material comprises an analyte.
Moreover the method includes determining a difference between a
first resonant frequency shift in the first set of sensors of the
plurality of sensors and a second resonant frequency shift in the
second set of sensors of the plurality of sensors.
Inventors: |
Rhoads; Jeffrey Frederick;
(Lafayette, IN) ; Nauman; Eric A.; (West
Lafayette, IN) ; Tweardy; Mackenzie; (West Lafayette,
IN) ; Wadas; Michael; (West Lafayette, IN) ;
Murray; Allison Kelly; (Canton, IN) ; Chiu; George
Tsu-Chih; (West Lafayette, IN) ; Bajaj; Nikhil;
(West Lafayette, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Purdue Research Foundation |
West Lafayette |
IN |
US |
|
|
Assignee: |
Purdue Research Foundation
West Lafayette
IN
|
Family ID: |
1000005841739 |
Appl. No.: |
17/172078 |
Filed: |
February 10, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16040504 |
Jul 19, 2018 |
10948489 |
|
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17172078 |
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62534374 |
Jul 19, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07K 16/18 20130101;
G01N 2333/4727 20130101; G01N 33/54373 20130101; C08L 25/06
20130101; G01N 33/54393 20130101; G01N 33/547 20130101 |
International
Class: |
G01N 33/543 20060101
G01N033/543; G01N 33/547 20060101 G01N033/547; C07K 16/18 20060101
C07K016/18 |
Claims
1. A method of detecting a substance, wherein the method comprises:
functionalizing a plurality of sensors, wherein the functionalizing
the plurality of sensors comprises depositing a first material,
wherein the first material comprises a polymer, a receptor, and a
solvent, wherein the solvent comprises dimethylformamide;
evaporating a solution from the first material, wherein a residue
after the evaporation comprises a functionalized chemical;
introducing a control material to a first set of sensors of the
plurality of sensors; introducing a test material to a second set
of sensors of the plurality of sensors, wherein the test material
comprises an analyte; and determining a difference between a first
resonant frequency shift in the first set of sensors of the
plurality of sensors and a second resonant frequency shift in the
second set of sensors of the plurality of sensors.
2. The method of claim 1, wherein the polymer comprises polystyrene
and the receptor comprises anti-s100.beta..
3. The method of claim 2, wherein the depositing the first material
comprises depositing an amount of the suspension of polystyrene and
anti-s100.beta. in dimethylformamide on each sensor of the
plurality of sensors, wherein the amount ranges from approximately
10.sup.-12 liters to approximately 10 milliliters.
4. The method of claim 3, wherein a concentration of polystyrene
ranges from approximately 0.01 milligrams per milliliter to
approximately 10 milligrams per milliliter, and a concentration of
anti-s100.beta. ranges from 0.01 milligrams per milliliter to
approximately 10 milligrams per milliliter.
5. The method of claim 1, wherein the solution of the first
material comprises dimethylformamide.
6. The method of claim 1, wherein the residue comprises a coating,
wherein the coating comprises polystyrene and anti-s100.beta..
7. The method of claim 1, wherein the control material comprises
phosphate buffered saline or water.
8. The method of claim 1, wherein the introducing the control
material comprises introducing an amount of the control material to
each sensor of the first set of sensors of the plurality of
sensors, wherein the amount ranges from approximately 10.sup.-12
liters to approximately 10 milliliters.
9. The method of claim 1, wherein the analyte comprises
s100.beta..
10. The method of claim 1, wherein the introducing the test
material comprises introducing an amount of the test material to
each sensor of the second set of sensors of the plurality of
sensors, wherein the amount ranges from approximately 10.sup.-12
liters to approximately 10 milliliters.
11. The method of claim 9, wherein a concentration of s100.beta.
ranges from approximately 10.sup.-12 grams per milliliter to
approximately 10 milligrams per milliliter.
12. The method of claim 1, wherein the determining the resonant
frequency shift comprises using a lock-in amplifier.
13. The method of claim 1, wherein each sensor of the plurality of
sensors is a quartz crystal resonator.
14. The method of claim 1, wherein each sensor of the plurality of
sensors has a dimension of 3.2 mm by 2.5 mm.
15. The method of claim 2, wherein the depositing the first
material comprises depositing an amount of the suspension of
polystyrene and anti-s100.beta. in dimethylformamide on each sensor
of the plurality of sensors, wherein the amount is approximately 5
nano-liters.
16. The method of claim 3, wherein a concentration of polystyrene
is approximately 1.333 mg/mL and a concentration of anti-s100.beta.
is approximately 0.106 mg/mL.
17. The method of claim 1, wherein the introducing the control
material comprises introducing 5.0 nL of the control material to
each sensor of the first set of sensors of the plurality of
sensors.
18. The method of claim 9, wherein a concentration of s100.beta. is
19.6 .mu.g/mL.
19. The method of claim 1, wherein the introducing the test
material comprises introducing 5.0 nL of the test material to each
sensor of the second set of sensors of the plurality of
sensors.
20. The method of claim 1, wherein the polymer comprises
polycarbonate, Poly(methyl methacrylate), Acrylonitrile butadiene
styrene, a synthetic polymer, Polybenzimidazole, Polycarbonate,
Polyether sulfone, polyoxymethylene, polyetherether ketone,
polyetherimide, polyethylene, polypropylene, or Poly(lactic acid).
Description
TECHNICAL FIELD
[0001] The present application relates to a method of detecting a
substance by determining first resonant frequency shift.
BACKGROUND
[0002] Piezoelectrically transduced resonant microsystems have
emerged as a promising detection tool. Their high sensitivities
make them excellent candidates for the mass-based detection of
substances such as biomarkers, metals, biological compounds etc.
Detection of some of these substances can help diagnose certain
diseases and medical conditions, or even be helpful in other
industries.
SUMMARY
[0003] The mechanism for detection relies on the relationship
between the mass and resonant frequency of a lumped-mass system.
The relationship is denoted by .omega..sup.2=K/m, where w is the
resonant frequency, K is the effective spring constant and m is the
effect mass associated with the vibration mode of interest. The
mass added to the resonator as a result of the adsorption of a
substance (such as a biomarker), .DELTA.m, is then approximated as:
.DELTA.m=K((1/.omega..sub.1.sup.2)-(1/.omega..sub.2.sup.2)),
wherein .omega..sub.1.sup.2 and with .omega..sub.1.sup.2 are the
resonant frequencies of the resonator before and after the
adsorption of the substance, respectively. This relationship
implies that a change in the mass on the surface of a resonator
caused by the binding of the substance will induce a resonant
frequency shift. Furthermore, the sensitivity of the resonator
increases as the resonant frequency increases, making
high-frequency resonators excellent candidates for biomarker
detection. If the surface of such a resonator can be functionalized
to allow for the specific adsorption of a biomarker, metal, or of a
biological compound of interest, the binding of that substance will
cause a change in mass that is detectable via frequency response
analysis.
[0004] One aspect of the present disclosure includes a method of
detecting a substance, wherein the method includes functionalizing
a plurality of sensors, wherein the functionalizing the plurality
of sensors comprises depositing a first material using a
piezoelectrically actuated pipette system, wherein the first
material includes a polymer, a receptor, and a solvent, wherein the
solvent comprises dimethylformamide. The method further includes
evaporating a solution of the first material, wherein a residue
after the evaporation comprises a functionalized chemical.
Additionally, the method includes introducing a control material to
a first set of sensors of the plurality of sensors using the
piezoelectrically actuated pipette system. Further, the method
includes introducing a test material to a second set of sensors of
the plurality of sensors using the piezoelectrically actuated
pipette system, wherein the test material comprises an analyte.
Moreover the method includes determining a difference between a
first resonant frequency shift in the first set of sensors of the
plurality of sensors and a second resonant frequency shift in the
second set of sensors of the plurality of sensors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] One or more embodiments are illustrated by way of example,
and not by limitation, in the figures of the accompanying drawings,
wherein elements having the same reference numeral designations
represent like elements throughout. It is emphasized that, in
accordance with standard practice in the industry, various features
may not be drawn to scale and are used for illustration purposes
only. In fact, the dimensions of the various features in the
drawings may be arbitrarily increased or reduced for clarity of
discussion.
[0006] FIG. 1 illustrates a method of detecting a substance in
accordance with one or more embodiments.
[0007] FIG. 2 illustrates a 16 MHz plate-style resonator prior to
and after functionalization, in accordance with one or more
embodiments.
[0008] FIG. 3 illustrates a piezoelectrically actuated pipette
system, in accordance with one or more embodiments.
[0009] FIG. 4 illustrates a frequency response of a 16 MHz
resonator driven by a 200 mV amplitude signal both before and after
exposure to a solution of PBS containing s100.beta., in accordance
with one or more embodiments.
[0010] FIG. 5 illustrates frequency shifts of 28 resonators in an
experimental group that were exposed to PBS and s100.beta. and 19
sensors in the control group that were exposed to PBS only, in
accordance with one or more embodiments.
DETAILED DESCRIPTION
[0011] In the following description, some aspects will be described
in terms that would ordinarily be implemented as software programs.
Those skilled in the art will readily recognize that the equivalent
of such software can also be constructed in hardware, firmware, or
micro-code. Because data-manipulation algorithms and systems are
well known, the present description will be directed in particular
to algorithms and systems forming part of, or cooperating more
directly with, systems and methods described herein. Other aspects
of such algorithms and systems, and hardware or software for
producing and otherwise processing the signals involved therewith,
not specifically shown or described herein, are selected from such
systems, algorithms, components, and elements known in the art.
Given the systems and methods as described herein, software not
specifically shown, suggested, or described herein that is useful
for implementation of any aspect is conventional and within the
ordinary skill in such arts.
[0012] Various embodiments of the present disclosure relate to
methods of detecting a substance. In one or more embodiments, the
present methodology can be used for a wide variety of analytes such
as such as biomarkers, metals, biological compounds, etc. In at
least one embodiment, the versatility of the present process allows
for a wide range of polymers and their associated solvents to be
used for the purposes of functionalizing the sensors with
receptors. A non-exhaustive list of receptor-analyte combination,
along with polymer-solvent combination is disclosed herein as well.
Based on the explanation in the Summary section, differences in
resonances between when the potential analyte is adsorbed by the
receptor, and the control material are calculated, thereby
rendering differences in mass. These differences in mass help
identify if there is a presence of an analyte of interest.
[0013] FIG. 1 is a flow chart of a method of detecting a substance
in accordance with one or more embodiments. Method 100 begins with
operation 105 which includes functionalizing a plurality of
sensors, wherein the functionalizing the plurality of sensors
comprises depositing a first material using a piezoelectrically
actuated pipette system, wherein the first material comprises a
polymer, a receptor, and a solvent. The deposition techniques in
operation 105 include inkjet printing, evaporation based
deposition, or spin coat deposition. Method 100 then continues with
operation 110 which includes evaporating a solution from the first
material, wherein a residue after the evaporation comprises a
functionalized chemical.
[0014] Method 100 continues with operation 115 which includes
introducing a control material to a first set of sensors of the
plurality of sensors using the piezoelectrically actuated pipette
system. Method 100 further continues with operation 120 which
includes introducing a test material to a second set of sensors of
the plurality of sensors using the piezoelectrically actuated
pipette system, wherein the test material comprises an analyte.
Method 100 additionally continues with operation 125 which includes
determining a difference between a first resonant frequency shift
in the first set of sensors of the plurality of sensors and a
second resonant frequency shift in the second set of sensors of the
plurality of sensors.
[0015] In at least one embodiment as it relates to method 100, the
polymer includes polystyrene, the receptor includes
anti-s100.beta., the solvent includes dimethylformamide, and the
analyte includes s100.beta.. In at least one embodiment, the
depositing the first material includes depositing an amount of the
suspension or solution of polymer (e.g. polystyrene) and receptor
(e.g. anti-s100.beta.) in solvent (e.g. dimethylformamide) on each
sensor of the plurality of sensors. In some embodiments, the amount
ranges from approximately 10.sup.-12 liters to approximately 10
milliliters. In some embodiments, the amount is approximately 5
nano-liters.
[0016] In one or more embodiments, a concentration of polymer (e.g.
polystyrene) ranges from approximately 0.01 milligrams per
milliliter to approximately 10 milligrams per milliliter, and a
concentration of receptor (e.g. anti-s100.beta.) ranges from
approximately 0.01 milligrams per milliliter to approximately 10
milligrams per milliliter. In some embodiments, a concentration of
polymer (e.g. polystyrene) is approximately 1.333 mg/mL and a
concentration of receptor (e.g. anti-s100.beta.) is approximately
0.106 mg/mL. In some embodiments, the solution of the first
material includes dimethylformamide, or another chemical, depending
on the type of solvent used for the polymer.
[0017] After the evaporation step (i.e. operation 110), the residue
is a coating of a polymer (e.g. polystyrene) and a receptor (e.g.
anti-s100.beta.). Because this coating is functionalized, it is now
able to adsorb specific substances (such as s100.beta.).
[0018] Operation 115 additionally includes the control material,
where the control material includes phosphate buffered saline, an
inert substance, a protein that is neither the receptor or the
analyte, or water. The amount of control material to each sensor
ranges from approximately 10.sup.-12 liters to approximately 10
milliliters. In some embodiments, the introducing the control
material includes introducing 5.0 nL of the control material to
each sensor of the first set of sensors of the plurality of
sensors.
[0019] Operation 120 additionally includes introducing an amount of
the test material to each sensor of the second set of sensors of
the plurality of sensors. In some embodiments, the amount ranges
from approximately 10.sup.-12 liters to approximately 10
milliliters. In at least one embodiment, the analyte of operation
120 includes s100.beta.. In one or more embodiments, a
concentration of analytes (e.g. s100.beta.) ranges from
approximately 10.sup.-12 grams per milliliter to approximately 10
milligrams per milliliter. In some embodiments, a concentration of
analytes (e.g. s100.beta.) is approximately 19.6 .mu.g/mL. In at
least one embodiment, the introducing the test material includes
introducing 5.0 nL of the test material to each sensor of the
second set of sensors of the plurality of sensors.
[0020] Operation 125 additionally includes determining the resonant
frequency shift using a lock-in amplifier, in at least one
embodiment. In one or more embodiments, each sensors of the
plurality of sensors in method 100 is a quartz crystal resonator,
MEMs resonator, or a nano resonator. In some embodiments, each
sensor of the plurality of sensors has a dimension of 3.2 mm by 2.5
mm. In some embodiments, each sensor of the plurality of sensors
has a dimension of X mm by Y mm, where X ranges from 10.sup.-6 m to
10 mm and Y ranges from 10.sup.-6 m to 10 mm.
[0021] The polymer used in the above process includes
polycarbonate, Poly(methyl methacrylate), Acrylonitrile butadiene
styrene, a synthetic polymer, Polybenzimidazole, Polycarbonate,
Polyether sulfone, polyoxymethylene, polyetherether ketone,
polyetherimide, polyethylene, polypropylene, or Poly(lactic
acid).
[0022] One of ordinary skill in the art would recognize that
operations are added or removed from method 100, in one or more
embodiments. One of ordinary skill in the art would also recognize
that an order of operations in method 100 is able to be changed, in
some embodiments. A non-exhaustive, but exemplary list of polymers
and their associated solvents which can be used in method 100 is
illustrated in Table 1. Additionally, a non-exhaustive, but
exemplary list of receptors and their associated analytes which can
be used in method 100 is illustrated in Table 2.
TABLE-US-00001 TABLE 2 Analyte Receptor/anti-body Alpha-Synuclein
Alpha-Synuclein antibody A.beta.40 A.beta.40 antibody A.beta.42
A.beta.42 antibody BDNF BDNF antibody c-MET c-MET antibody
C-Peptide C-Peptide antibody CA 19-9 CA 19-9 antibody CA-125 CA-125
antibody Cathepsin S Cathepsin S CCL-11/Eotaxin Assay Kit
CCL-11/Eotaxin Assay Kit antibody CEA CEA antibody CRP CRP antibody
CXCL13 CXCL13 antibody Cytokine 3-Plex A TNF.alpha., Cytokine
3-Plex A TNF.alpha., IL-6, IL-10 IL-6, IL-10 antibody Cytokine
3-Plex B TNF.alpha., Cytokine 3-Plex B TNF.alpha., IL-6, IL-17A
IL-6, IL-17A antibody G-CSF G-CSF antibody GFAP GFAP antibody
GM-CSF GM-CSF antibody GM-CSF (mouse) GM-CSF (mouse) antibody
HE4/WFDC2 HE4/WFDC2 antibody HIV p24 HIV p24 antibody IFN-.gamma.
IFN-.gamma. antibody IFN.alpha. IFN.alpha. antibody IL-10 IL-10
antibody IL-12 p70 IL-12 p70 antibody IL-12p40/IL-23 IL-12p40/IL-23
antibody IL-13 IL-13 antibody IL-15 IL-15 antibody IL-17A IL-17 A
antibody IL-17A (mouse) IL-17A (mouse) antibody IL-17A/F (mouse)
IL-17A/F (mouse) antibody IL-17C IL-17C antibody IL-17F IL-17F
antibody IL-17F (mouse) IL-17F (mouse) antibody IL-18 IL-18
antibody IL-1.alpha. IL-1.alpha. antibody IL-1.alpha. (mouse)
IL-1.alpha. (mouse) antibody IL-1.beta. IL-1.beta. antibody
IL-1.beta. (mouse) IL-1.beta. (mouse) antibody IL-2 IL-2 antibody
IL-22 (mouse) IL-22 (mouse) antibody IL-22 (Total) IL-22 (Total)
antibody IL-23 IL-23 antibody IL-23 (mouse) IL-23 (mouse) antibody
IL-28A IL-28A antibody IL-3 IL-3 antibody IL-33 IL-33 antibody
IL-363 IL-363 antibody IL-4 IL-4 antibody IL-6 IL-6 antibody IL-6
(mouse) IL-6 (mouse) antibody IL-8 IL-8 antibody IP-10 IP-10
antibody Leptin Leptin antibody LIF LIF antibody MCP-1 MCP-1
antibody MCP-3 MCP-3 antibody MIP-1.beta. MIP-1.beta. antibody
NF-light .RTM. NF-light .RTM. antibody NSE NSE antibody NT-proBNP
NT-proBNP antibody PD-1 PD-1 antibody PD-L1 PD-L1 antibody PIGF
PIGF antibody pNF-Heavy pNF-Heavy antibody PSA PSA antibody Tau Tau
antibody Tau (mouse) Tau (mouse) antibody TGF.alpha. TGF.alpha.
antibody TGF.beta. TGF.beta. antibody TNF.alpha. TNF.alpha.
antibody TNF.alpha. (mouse) TNF.alpha. (mouse) antibody TNF.beta.
TNF.beta. antibody TRAIL TRAIL antibody Troponin-I Troponin-I
antibody UCH-L1 UCH-L1 antibody VEGF VEGF antibody lead EDTA
(Ethylenediaminetetraacetic acid), DMSA (dimercaptosuccinic acid),
or N-acetylcysteine chromium N-acetylcysteine arsenic Thiolates,
amines, or dimercaprol mercury DMPS (sodium 2,3-dimercaptopropane
1-sulfonate)
[0023] Example 1: In one or more embodiments, an analyte which can
be identified using the above method is a biomarker by the name
s100.beta., a protein closely associated with Traumatic Brain
Injury (TBI). The concentrations of s100.beta. in the cerebrospinal
fluid of TBI victims immediately after injury typically increase
from several ng/ml to several hundreds of ng/ml, making it a
promising diagnostic biomarker for TBI.
[0024] The example starts off with using Plate-style, 16 MHz quartz
crystal resonators (Kyocera Corp., CX3225) which act as the
biomarker sensors. A single resonator measures 3.20 mm by 2.50 mm
and can be seen in FIG. 2. Each sensor was integrated with a
circuit that enables its frequency response characterization via an
HF2LI Lock-In Amplifier (Zurich Instruments). The characterization
was achieved with 1 Hz resolution over a 300 Hz frequency range
containing the sensor's resonant frequency. From the frequency
response, the peak frequency was taken to be the frequency that
yields the highest magnitude output. Any shift in the peak
frequency was assumed to be equivalent to a corresponding shift in
the resonant frequency, an approximation supported by the high
Q-factor of the resonators. A shift in the peak frequency therefore
indicated an increase in mass on the surface of the resonator, thus
enabling the detection of s100.beta..
[0025] To functionalize the sensors, polystyrene and
anti-s100.beta. (Abcam, 100 .mu.L) were suspended in
dimethylformamide (DMF), to create a solution of 1.333 mg/mL
polystyrene and 0.106 mg/mL anti-s100.beta. in DMF. A
piezoelectrically actuated pipette system (BioFluidix) was used to
deposit 5.0 nL of this solution onto each sensor, as shown in FIG.
3. A close up view of a sensor after the solution was deposited is
shown in FIG. 2.
[0026] The DMF was subsequently allowed to evaporate over a period
of approximately 3 h. This resulted in functionalized sensors with
a polystyrene/anti-s100.beta. coating that allowed for the
adsorption of s100.beta.. Polystyrene was chosen as a coating due
to its relatively low damping on the frequency response of the
resonators as compared to other polymers. Anti-s100.beta. was
chosen to functionalize the sensors because of its high degree of
specificity and affinity for s100.beta.. DMF was chosen as the
solvent because of its high evaporation rate and its ability to
dissolve polystyrene without denaturing anti-s100.beta..
[0027] Confocal imaging was performed to confirm that the surface
of the functionalized sensors would promote the adsorption of
s100.beta.. A functionalized sensor was exposed via micropipette to
a solution of phosphate buffered saline (PBS) (Abcam) and a
fluorescent conjugation of s100.beta. containing a dye known as
Alexa Fluor (Abcam, 100 .mu.L). The exposed resonator was
subsequently imaged with a confocal microscope to confirm the
success of the functionalization. A 20.times. air lens was used
with a pinhole size of 18.01 AU, a laser intensity of 2%, a gain of
750, and a 1.58 .mu.s pixel dwell time. The fluorescent images
taken confirmed the adsorption of the Alexa Fluor onto the surface
of the resonator, validating the functionalization technique.
[0028] Forty seven sensors were functionalized as described. After
functionalization, the frequency response of each sensor was
obtained using the aforementioned experimental setup. An
experimental group of 28 sensors was then exposed to 5.0 nL of a
19.6 .mu.g/mL solution of s100.beta. (Abcam, 500 .mu.g) in PBS
deposited directly onto the surface of the sensor using the
piezoelectrically actuated pipette system. A control group of 19
separate sensors was exposed to 5.0 nL of PBS in the same manner.
All of the sensors were subsequently rinsed with 5.0 nL of
deionized water deposited onto each resonator again using the
piezoelectrically actuated pipette system. After drying over a
period of approximately 3 h, the frequency response of each sensor
was again obtained.
[0029] Next, the relative shift in resonant frequency between the
experimental group and the control group is calculated. An example
of this shift is shown in FIG. 4. The resonant frequency shift of
the sensor represented in FIG. 4 after exposure to s100.beta. was
23244 Hz. The resonant frequency shifts of all of the sensors
tested are presented in FIG. 5. The average frequency shift among
the 28 resonators in the experimental group was 13704 Hz with a
standard deviation of 6259 Hz. The average frequency shift among
the 19 resonators in the control group was 1504 Hz with a standard
deviation of 11431 Hz. Therefore, the average difference in the
frequency shift between the experimental and control groups was
12200 Hz.
[0030] A one-sided, two-sample t-test was performed challenging the
null hypothesis that the frequency shift experienced by the
experimental group is equal to the frequency shift of the control
group. The alternative hypothesis states that the average frequency
shift experienced by the sensors in the experimental group is
greater than the average frequency shift of the sensors in the
control group. A small significance level of .alpha.=0.001 was
chosen in order to minimize the risk of a Type I error. The
resulting probability value was p=0.000012. Therefore, the null
hypothesis was rejected, and the experiment provides strong
statistical evidence of the successful detection of s100.beta..
[0031] The total amount of s100.beta. deposited onto the sensors in
the experimental group, determined by multiplying the concentration
of s100.beta. in the exposure solution by the volume deposited, was
approximately 98 pg. This corresponds to an overall sensor
sensitivity of 124.49 Hz/pg. This is theoretically sufficient to
enable the detection of s100.beta. in victims of TBI, who typically
have s100.beta. concentrations on the order of hundreds of ng/ml in
their cerebrospinal fluid.
[0032] The invention is inclusive of combinations of the aspects
described herein. References to "a particular aspect" and the like
refer to features that are present in at least one aspect of the
invention. Separate references to "an aspect" (or "embodiment") or
"particular aspects" or the like do not necessarily refer to the
same aspect or aspects; however, such aspects are not mutually
exclusive, unless so indicated or as are readily apparent to one of
skill in the art. The use of singular or plural in referring to
"method" or "methods" and the like is not limiting. The word "or"
is used in this disclosure in a non-exclusive sense, unless
otherwise explicitly noted.
[0033] Although the present disclosure and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the disclosure as defined by the
appended claims. Moreover, the scope of the present application is
not intended to be limited to the particular embodiments of the
process, machine, manufacture, and composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure, processes, machines, manufacture, compositions of
matter, means, methods, or steps, presently existing or later to be
developed, that perform substantially the same function or achieve
substantially the same result as the corresponding embodiments
described herein may be utilized according to the present
disclosure. Accordingly, the appended claims are intended to
include within their scope such processes, machines, manufacture,
compositions of matter, means, methods, or steps.
* * * * *