U.S. patent application number 17/166204 was filed with the patent office on 2021-06-17 for surface enhanced raman scattering substrate assembly.
The applicant listed for this patent is University of Massachusetts. Invention is credited to Haoxin Chen, Lili He, Zhuansheng Lin.
Application Number | 20210181115 17/166204 |
Document ID | / |
Family ID | 1000005420028 |
Filed Date | 2021-06-17 |
United States Patent
Application |
20210181115 |
Kind Code |
A1 |
He; Lili ; et al. |
June 17, 2021 |
SURFACE ENHANCED RAMAN SCATTERING SUBSTRATE ASSEMBLY
Abstract
The present disclosure provides a surface enhanced Raman
scattering substrate assembly for detecting an analyte. The
assembly can include an etched fiber base. The assembly can further
include a metallic nanoparticle coating disposed over at least a
portion of the surface etched fiber base.
Inventors: |
He; Lili; (Belchertown,
MA) ; Chen; Haoxin; (Amherst, MA) ; Lin;
Zhuansheng; (Boston, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
University of Massachusetts |
Boston |
MA |
US |
|
|
Family ID: |
1000005420028 |
Appl. No.: |
17/166204 |
Filed: |
February 3, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16439186 |
Jun 12, 2019 |
10942124 |
|
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17166204 |
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62685102 |
Jun 14, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 33/025 20130101;
G01N 21/658 20130101 |
International
Class: |
G01N 21/65 20060101
G01N021/65; G01N 33/02 20060101 G01N033/02 |
Goverment Interests
STATEMENT OF GOVERNMENT SUPPORT
[0002] This invention was made with Government support under Grant
#USDA-NIFA 2016-67017-24458 awarded by the National Institute of
Food and Agriculture of the United States Department of
Agriculture. The U.S. Government has certain rights in this
invention.
Claims
1. A method for detecting an analyte, the method comprising:
contacting an etched fiber base with a medium to collect the
analyte from the medium on the etched fiber base, wherein a
metallic nanoparticle coating is disposed over at least a portion
of an external surface of the etched fiber base, the metallic
nanoparticle coating comprising metallic nanoparticles that have a
largest dimension of about 25 nm to about 500 nm; and contacting
the etched fiber base comprising the analyte with an
electromagnetic emission.
2. The method of claim 2, further comprising identifying or
quantifying an analyte in the medium from the spectrum.
3. The method of claim 1, further comprising identifying an analyte
in the medium from the spectrum.
4. The method of claim 1, wherein the etched fiber base is located
in at least one of a gaseous phase, a liquid phase, or a solid
phase.
5. The method of claim 1, wherein the etched fiber base and the
medium are located in a sealed environment.
6. The method of claim 1, wherein the electromagnetic emission is a
laser emission.
7. The method of claim 1, wherein the analyte is an indicator of a
response to biotic stress.
8. The method of claim 1, further comprising heating the analyte to
a temperature sufficient to put the analyte into a gaseous
phase.
9. The method of claim 1, wherein the analyte is chosen from a
pesticide, a metabolite, a pathogen, a bacteria, a fungi, a virus,
an enzyme, a reactive oxygen species, and a mixture thereof.
10. The method of claim 9, wherein the pesticide is chosen from
O-Ethyl S-phenyl ethylphosphonodithioate, thiabendazole,
acetamiprid, iron tris(dimethyldithiocarbamate), phosmet, phorate,
isocarbophos, and mixtures thereof.
11. The method of claim 9, wherein the metabolite is chosen from
salicylic acid, phytoalexin, sulfonic acid, diphenyl sulfide, allyl
methyl sulfide, and a mixture thereof.
12. The method of claim 9, wherein the enzyme is chosen from flavin
adenine dinucleotide, nicotinamide adenine dinucleotide phosphate
oxidase, and mixtures thereof.
13. The method of claim 9, wherein the bacteria is chosen from a
gram-positive bacteria, a gram-negative bacteria, and mixtures
thereof.
14. The method of claim 13, wherein the bacteria is chosen from
Clostridium botulinum, Listeria monocytogenes, Acetic acid
bacteria, Acidaminococcus, Acinetobacter baumannii, Agrobacterium
tumefaciens, Akkermansia muciniphila, Anaerobiospirillum,
Anaerolinea thermolimosa, Anaerolinea thermophila, Arcobacter,
Arcobacter skirrowii, Armatimonas rosea, Azotobacter salinestris,
Bacteroides, Bacteroides fragilis, Bacteroides ureolyticus,
Bacteroidetes, Bartonella japonica, Bartonella koehlerae,
Bartonella taylorii, Bdellovibrio, Brachyspira, Bradyrhizobium
japonicum, Caldilinea aerophile, Cardiobacterium hominis,
Chaperone-Usher fimbriae, Christensenella, Chthonomonas
calidirosea, Coxiella burnetiid, Cyanobacteria, Cytophaga,
Dehalogenimonas lykanthroporepellens, Desulfurobacterium
atlanticum, Devosia pacifica, Devosia psychrophila, Devosia soli,
Devosia subaequoris, Devosia submarina, Devosia yakushimensis,
Dialister, Dictyoglomus thermophilum, Enterobacter, Enterobacter
cloacae, Enterobacter cowanii, Enterobacteriaceae,
Enterobacteriales, Escherichia, Escherichia coli, Escherichia
fergusonii, Escherichia hermannii, Fimbriimonas ginsengisoli,
Flavobacterium, Flavobacterium akiainvivens, Francisella novicida,
Fusobacterium necrophorum, Fusobacterium nucleatum, Fusobacterium
polymorphum, Haemophilus felis, Haemophilus haemolyticus,
Haemophilus influenzae, Haemophilus pittmaniae, Helicobacter,
Kingella kingae, Klebsiella pneumoniae, Kluyvera ascorbate,
Kluyvera cryocrescens, Legionella, Legionella clemsonensis,
Legionella pneumophila, Leptonema illini, Leptotrichia buccalis,
Levilinea saccharolytica, Luteimonas aquatic, Luteimonas composti,
Luteimonas lutimaris, Luteimonas marina, Luteimonas mephitis,
Luteimonas vadose, Megamonas, Megasphaera, Meiothermus, Meiothermus
timidus, Methylobacterium fujisawaense, Morax-Axenfeld
diplobacilli, Moraxella, Moraxella bovis, Moraxella osloensis,
Morganella morganii, Mycoplasma spumans, Neisseria cinereal,
Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria
polysaccharea, Neisseria sicca, Nitrosomonas eutropha, Nitrosomonas
halophila, Nonpathogenic organisms, OMPdb, Pectinatus, Pedobacter
heparinus, Pelosinus, Propionispora, Proteobacteria, Proteus
mirabilis, Proteus penneri, Pseudomonas, Pseudomonas aeruginosa,
Pseudomonas luteola, Pseudoxanthomonas broegbernensis,
Pseudoxanthomonas japonensis, Rickettsia rickettsia, Salinibacter
ruber, Salmonella, Salmonella bongori, Salmonella enterica,
Samsonia, Selenomonadales, Serratia marcescens, Shigella,
Shimwellia, Solobacterium moorei, Sorangium cellulosum,
Sphaerotilus natans, Sphingomonas gei, Spirochaeta,
Spirochaetaceae, Sporomusa, Stenotrophomonas, Stenotrophomonas
nitritireducens, Thermotoga neapolitana, Thorselliaceae, Trimeric
autotransporter adhesion, Vampirococcus, Verminephrobacter, Vibrio
adaptatus, Vibrio azasii, Vibrio campbellii, Vibrio cholerae,
Victivallis vadensis, Vitreoscilla, Wolbachia, Yersiniaceae,
Zymophilus, strains thereof, and mixtures thereof.
15. The method of claim 1, wherein the medium comprises a food, a
beverage, a plant, an animal, a breath, or a mixture thereof.
16. The method of claim 15, wherein the food is chosen from a
vegetable, a fruit, a meat, a dairy product, a grain, and mixtures
thereof.
17. The method of claim 15, wherein the beverage is chosen from
milk, beer, wine, water, juice, coffee, tea, and mixtures
thereof.
18. The method of claim 1, further comprising detecting the
analyte.
19. The method of claim 1, further comprising generating a
spectrum.
20. The method of claim 1, wherein the etched fiber base has a
length range from about 3 cm to about 6 cm.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/439,186, filed Jun. 12, 2019, which claims
the benefit of priority to U.S. Patent Provisional Application No.
62/685,102, filed Jun. 14, 2018, which are incorporated by
reference herein in their entireties.
BACKGROUND
[0003] Surface enhanced Raman scattering (SERS) can be useful for
many different applications. For example, SERS can be used to
detect a wide variety of biomolecules, metabolites, or other
materials. However, a lack of portability of SERS devices and the
ability to accomplish real-time detection of analytes are problems
with some SERS systems. There is a need therefore, for improving
the portability and real-time detection of SERS systems.
SUMMARY OF THE DISCLOSURE
[0004] The present disclosure provides a surface enhanced Raman
scattering substrate assembly for detecting an analyte. The
assembly can include an etched fiber base. The assembly can further
include a metallic nanoparticle coating disposed over at least a
portion of the surface etched fiber base.
[0005] The present disclosure further provides a method for
detecting an analyte. The method includes contacting an etched
fiber base with a medium. The method further includes contacting
the medium with an electromagnetic emission. The method further
includes detecting the analyte and generating a spectrum.
[0006] The present disclosure further provides a method of making a
surface enhanced Raman scattering substrate assembly for detecting
an analyte. The assembly can include an etched fiber base. The
assembly can further include a metallic nanoparticle coating
disposed over at least a portion of the surface etched fiber base.
The method includes etching a fiber to form an etched fiber base.
The method further includes coating metallic nanoparticles on the
surface of the etched fiber base.
BRIEF DESCRIPTION OF THE FIGURES
[0007] The drawings illustrate generally, by way of example, but
not by way of limitation, various embodiments discussed in the
present document.
[0008] FIG. 1 is a schematic depiction of a surface enhanced Raman
scattering substrate assembly, in accordance with various
embodiments.
[0009] FIGS. 2A-2B are a schematic depictions of a needle for a
SERS substrate assembly, in accordance with various
embodiments.
[0010] FIG. 3 is a schematic depiction of a method of making and
using a surface enhanced Raman scattering substrate assembly, in
accordance with various embodiments.
[0011] FIGS. 4A-4H are scanning electron microscope (SEM) images
showing etched fibers and coated etched fibers, in accordance with
various embodiments.
[0012] FIG. 5 shows spectra generated from the surface enhanced
Raman scattering substrate assembly, in accordance with various
embodiments.
[0013] FIGS. 6A-6B are a spectrum and concentration chart generated
from the surface enhanced Raman scattering substrate assembly, in
accordance with various embodiments.
[0014] FIGS. 7A-7B are spectra generated from the surface enhanced
Raman scattering substrate assembly, in accordance with various
embodiments.
[0015] FIG. 8 is a surface enhanced Raman scattering substrate
assembly, in accordance with various embodiments.
[0016] FIG. 9 are spectra generated from the surface enhanced Raman
scattering substrate assembly, in accordance with various
embodiments.
[0017] FIG. 10 is a schematic depiction of the surface enhanced
Raman scattering substrate assembly located partially within a
tomato, in accordance with various embodiments.
[0018] FIG. 11 is a spectrum generated from the surface enhanced
Raman scattering substrate assembly deployed in the tomato of FIG.
10, in accordance with various embodiments.
[0019] FIG. 12 is an SEM image showing pore size of an in-situ
filter, in accordance with various embodiments.
DETAILED DESCRIPTION
[0020] Reference will now be made in detail to certain embodiments
of the disclosed subject matter, examples of which are illustrated
in part in the accompanying drawings. While the disclosed subject
matter will be described in conjunction with the enumerated claims,
it will be understood that the exemplified subject matter is not
intended to limit the claims to the disclosed subject matter.
[0021] Throughout this document, values expressed in a range format
should be interpreted in a flexible manner to include not only the
numerical values explicitly recited as the limits of the range, but
also to include all the individual numerical values or sub-ranges
encompassed within that range as if each numerical value and
sub-range is explicitly recited. For example, a range of "about
0.1% to about 5%" or "about 0.1% to 5%" should be interpreted to
include not just about 0.1% to about 5%, but also the individual
values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to
0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The
statement "about X to Y" has the same meaning as "about X to about
Y," unless indicated otherwise. Likewise, the statement "about X,
Y, or about Z" has the same meaning as "about X, about Y, or about
Z," unless indicated otherwise.
[0022] In this document, the terms "a," "an," or "the" are used to
include one or more than one unless the context clearly dictates
otherwise. The term "or" is used to refer to a nonexclusive "or"
unless otherwise indicated. The statement "at least one of A and B"
has the same meaning as "A, B, or A and B." In addition, it is to
be understood that the phraseology or terminology employed herein,
and not otherwise defined, is for the purpose of description only
and not of limitation. Any use of section headings is intended to
aid reading of the document and is not to be interpreted as
limiting; information that is relevant to a section heading may
occur within or outside of that particular section.
[0023] In the methods described herein, the acts can be carried out
in any order without departing from the principles of the
disclosure, except when a temporal or operational sequence is
explicitly recited. Furthermore, specified acts can be carried out
concurrently unless explicit claim language recites that they be
carried out separately. For example, a claimed act of doing X and a
claimed act of doing Y can be conducted simultaneously within a
single operation, and the resulting process will fall within the
literal scope of the claimed process.
[0024] The term "about" as used herein can allow for a degree of
variability in a value or range, for example, within 10%, within
5%, or within 1% of a stated value or of a stated limit of a range
and includes the exact stated value or range.
[0025] The term "substantially" as used herein refers to a majority
of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%,
96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999%
or more, or 100%.
[0026] Analysis of target compounds (analytes) from complex
matrices, such as food or biological samples, is challenging with
traditional analytical methods. In particular, interference from
other components in the matrices can occur during analysis. For
this reason, many analytical processes involved complicated and
multi-step sample preparations to improve sensitivity of the
analysis. These processes can involve invasive and destructive
sampling.
[0027] Discussed herein is a method and assembly, in various
embodiments, that allows for high speed analysis of analytes in
complex matrices without destructive or invasive sampling. The
method and assembly can include, in various embodiments, a
micro-extraction device enabling in-situ extraction and detection
of analytes using surface enhanced Raman spectroscopy (SERS)
technology.
[0028] FIG. 1 is a schematic depiction of SERS substrate assembly
100. Surface enhanced Raman scattering substrate assembly 100 can
include many suitable components for detecting an analyte. Examples
of such components for surface enhanced Raman scattering substrate
assembly 100 include etched fiber base 102 and metallic
nanoparticle coating 104, which is disposed over at least a portion
of the surface of etched fiber base 102. Needle 106 at least
partially circumscribes etched fiber base 102. Needle 106 is an
optional component. If needle 106 is present, needle 106 may be any
suitable needle such as a hypodermic needle capable of puncturing a
material. Optionally, needle 106 can be used to puncture an opening
in the medium, then removed before etched fiber base 102 is
inserted. In some embodiments, assembly 100 is in a transparent
container to allow SERS analysis.
[0029] Etched fiber base 102 can include any suitable material.
Factors to consider in choosing the material include the ability
etch the material, the durability of the material at elevated
temperatures, and the ability of the material to participate in a
reduction reaction during coating of the nanoparticles of metallic
nanoparticle coating 104. An example of a suitable material for
etched fiber base 102 includes stainless steel. In other
embodiments, etched fiber base 102 may include copper, lead,
chromium, tin, magnesium, aluminum, zinc, manganese, calcium,
alloys thereof, and mixtures thereof.
[0030] Etched fiber base 102 can have any elongated suitable shape.
For example, etched fiber base 102 can be substantially
cylindrically shaped, substantially conically shaped, or
substantially rectangular shaped. Etched fiber base 102 can have
any suitable dimensions with respect to length Li or width Wi. The
term "length" is meant to apply to a largest dimension of etched
fiber base 102. In some embodiments the etched fiber base has a
length ranging from about 3 cm to about 6 cm. The term "width"
applies to a largest dimension of etched fiber base 102
substantially orthogonal to the length. In embodiments where etched
fiber base 102 is substantially cylindrically shaped, the width may
correspond to a largest diameter of etched fiber base 102. In some
embodiments the etched fiber base has a width ranging from about
100 .mu.m to about 400 .mu.m or from about 0.5 cm to about 5 cm.
Etched fiber base 102 can be, for example, from about 1 cm to about
10 cm (e.g., about 3 cm to about 6 cm). Etched fiber base 102 can
have, for example, a thickness of about 50 .mu.m to about 400 .mu.m
(e.g., about 50 .mu.m to about 100 .mu.m). Fiber length and
thickness can alternatively be determined based on the sample vial
or the sample itself, in addition to the needle size if a needle is
used.
[0031] Etched fiber base 102 can be etched to form a predetermined
pattern or a random pattern of grooves, depressions, ridges, pores,
or the like. Etching can be accomplished using any suitable method
such as acid etching or laser etching. Etching patterns may be
formed using a screen or mask to selectively expose certain regions
to the etchant.
[0032] Etching can be desirable for several reasons. For example,
etching a fiber increases the surface area of the fiber as compared
to a corresponding fiber that is free of etching, or etched to a
lesser degree, that shares substantially the same length and width
as etched fiber base 102. The increased surface area can be helpful
in embodiments where surface enhanced Raman scattering substrate
assembly 100 is used to detect an analyte in a liquid or gaseous
phase. This can be because the increased surface area increases the
contact points that the analyte has available to interact with upon
metallic nanoparticle coating 104. The increased surface area on
etched fiber base 102 can further allow for an increased number of
metallic nanoparticles to be included in metallic nanoparticle
coating 104.
[0033] Metallic nanoparticle coating 104 is dispersed over about
50% to about 100% of the total surface area of etched fiber base
102, about 70% to about 100%, about 90% to about 98%, or less than,
equal to, or greater than about 70%, 75, 80, 85, 90, 95, or about
100%. Metallic nanoparticle coating 104 includes a plurality of
metallic nanoparticles. The total surface area of etched fiber base
102 is the total external surface area inclusive of pores or other
non-planar aspects of the surface.
[0034] Individual metallic nanoparticles can include any suitable
material. For example, individual metallic nanoparticles of the
plurality of nanoparticles can include Ag.sub.2O, elemental silver,
elemental gold, elemental copper, elemental platinum, mixtures
thereof, alloys thereof, or combinations thereof. In some
embodiments, each metallic nanoparticle is the same material. For
example, in some embodiments of surface enhanced Raman scattering
substrate assembly 100 each metallic nanoparticle can include
elemental gold.
[0035] Individual metallic nanoparticles can have any suitable
morphology. For example, individual metallic nanoparticles can have
a morphology such as a nanosphere, a nanochain, a nanoreef, a
nanobox, or a nanostar. In some embodiments, each metallic
nanoparticle of metallic nanoparticle coating 104 can have the same
morphology. In other embodiments, however, metallic nanoparticle
coating 104 can include a mixture of metallic nanoparticles having
different morphologies. In some embodiments, surface enhanced Raman
scattering substrate assembly 100 can further include a layer of
metallic microparticles disposed on etched fiber base 102.
Microparticles are generally understood to refer to particles
individually having at least one dimeson (e.g., length, width,
thickness, diameter, or height) in the micrometer range. The
micrometer range can include any distance from about 1 .mu.m to
about 1000 .mu.m, about 100 .mu.m to about 500 .mu.m, or less than,
equal to, or greater than about 1 .mu.m, 100, 200, 300, 400, 500,
600, 700, 800, 900, or about 1000 .mu.m. Nanoparticles are
generally understood to refer to individual particles having at
least one dimension (e.g., length, width, thickness, diameter, or
height) in the nanometer range. The nanometer range can include any
distance from about 1 nm to about 10000 nm, about 100 nm to about
500 nm, or less than, equal to, or greater than about 1 nm, 1000,
2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, or about 10000
.mu.m. Individual metallic nanoparticles can have any suitable
size. For example, a largest dimension of an individual metallic
nanoparticle can be in a range of from about 25 nm to about 500 nm,
about 50 nm to about 100 nm, or less than, equal to, or greater
than about 25 nm, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85,
90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155,
160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220,
225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285,
290, 295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350,
355, 360, 365, 370, 375, 380, 385, 390, 400, 405, 410, 415, 420,
425, 430, 435, 440, 445, 450, 455, 460, 465, 470, 475, 480, 485,
490, 495, or about 500 nm.
[0036] Etched fiber base 102 having metallic nanoparticle coating
104 disposed thereon can be deployed into an environment as a
stand-alone component. Alternatively, etched fiber base 102 having
metallic nanoparticle 104 disposed thereon can be at least
partially disposed within another component. For example, as shown
in FIG. 1, etched fiber base 102 having metallic nanoparticle 104
disposed thereon is at least partially circumscribed and disposed
in needle 106. In other embodiments, etched fiber base 102 having
metallic nanoparticle 104 disposed thereon can be disposed at least
partially within a container such as a straw.
[0037] FIGS. 2A-2B are schematic depictions of a needle 206 for a
SERS substrate assembly (e.g., assembly 100 in FIG. 1). Needle 206
can include, for example, etched fiber base 202 and metallic
nanoparticle coating 204, which is disposed over at least a portion
of the surface of etched fiber base 202. Needle 206 at least
partially circumscribes etched fiber base 202. Assembly 200
additionally includes in-situ filter 208. Components 202 and 204,
are similar to the corresponding components described in reference
to FIG. 1 and are connected in a similar fashion.
[0038] FIG. 2A shows needle 206 separate from a medium. FIG. 2B
shows needle 206 in a medium 210 with analyte 212. The medium in
FIG. 2B can be a gaseous medium, a liquid medium, a semi-solid
medium, or a medium that is a mixture of states. For example, the
medium could be a gaseous or liquid solvent holding an analyte,
such as a beverage, or could be the interior of a fruit, vegetable,
meat, a dairy product, a grain, or other solid material being
tested for analytes as discussed in depth below.
[0039] In-situ filter 208 caps needle 206, allowing the medium and
analyte to pass through in-situ filter 208 prior to reaching etched
fiber base 202 with metallic nanoparticle coating 204. In-situ
filter 208 allows analyte to pass to etched fiber base 202 for
analysis but prevents impurities (i.e., other components of the
medium or matrix) from affecting etched fiber base 202. Examples of
impurities include a pesticide, a metabolite, a pathogen, a
bacteria, a fungi, a virus, an enzyme, a reactive oxygen species,
and a mixture thereof. These are discussed in more detail below.
Filtration by in-situ filter 208 can be mechanical (e.g.,
filtration by size of particles or impurities due to pore size of
filter 208) or chemical (e.g., filter 208 could include ligands or
other chemical components that are likely to capture certain
impurities). By reducing impurities, in-situ filter 208 also
increases sensitivity of etched fiber base 202 to the analyte of
interest.
[0040] Needle 206 can be a metallic (e.g., stainless steel copper,
lead, chromium, tin, magnesium, aluminum, zinc, manganese, calcium,
alloys thereof, and mixtures thereof), or plastic need suitable for
puncturing a material for example, a hypodermic needle. Needle 206
can be a hollow needle (e.g., an extraction needle shell). Needle
206 can have, for example, a tapered end to allow for puncturing of
a medium. In contrast, etched fiber base 202 can be blunt. In-situ
filter 208 can be integral with needle 206, and etched fiber base
202 can be inserted into needle 206. In some embodiments, etched
fiber base 202 is aligned with the outside end of needle 206.
Alternatively, etched fiber base 202 can extend beyond the outside
end of needle 206 (see, for example, FIG. 10).
[0041] In-situ filter 208 can, for example, cover just an end of
the needle 206, or partially cover the sides of the needle 206, or
can fill the end or a portion of needle 206, depending on the
extent of protection of etched fiber base 202 desired. In some
embodiments, protection of etched fiber base 202 with in-situ
filter 208 allows for "naked" etched fiber base 202 without
metallic nanoparticle coating 204.
[0042] In-situ filter 208 can be a polymeric porous membrane
attached to in needle 206. In-situ filter 208 can be made, for
example, by a polymer coating that can be cured to the end of
needle 206. For example, in-situ filter 208 can be made of
cellulose, nitrocellulose, polytetrafluoroethylene (PTFE), nylon,
polycarbonate, acrylic based polymers, methacrylic based polymers,
and combinations thereof. In-situ filter 208 can chemically or
physically immobilize active absorbents or catalytic compounds in
the medium. Alternatively, the in-situ filter 208 can remove or
breakdown interfering compounds from the medium.
[0043] In-situ filter 208 can be a porous material so as to allow
passage of the analyte through toward etched fiber base 202. This
can also allow in-situ filter 208 to have a large surface area for
absorbing or interacting with impurities. FIG. 12 shows an SEM
photograph of an example in-situ filter. In-situ filter 208 can
have, for example, an average pore size (across the longest point
of the pore) of about 5 .mu.m to about 35 .mu.m (i.e., about 10
.mu.m to about 25 .mu.m, preferably from about 12 .mu.m to about 20
.mu.m). In-situ filter 208 allows for passage of medium 212 through
into needle 206, where the medium is now filtered medium 211,
containing less impurities.
[0044] In-situ filter 208 can be pre-prepared and inserted into
needle 206 or prepared directly in needle 206 via in-situ
polymerization. The in-situ filter 208 can contain a cavity that
allows insertion of the etched fiber base 202.
[0045] In operation, surface enhanced Raman scattering substrate
assembly 100 or 200 can be used to detect an analyte. A method for
using surface enhanced Raman scattering substrate assembly 100 or
200, illustrated in FIG. 3, can include contacting etched fiber
base 102 or 202 having metallic nanoparticle 104 or 204 disposed
thereon with a medium. Etched fiber base 102 or 202 having metallic
nanoparticle 104 or 204 disposed thereon can then be removed from
contact with the medium and contacted with a laser emission. A
spectrum can then be generated and analyzed for the presence or
absence of an analyte. The amount of analyte present or the
concentration of the analyte in solution can also be quantitatively
determined from the spectrum that is generated.
[0046] Surface enhanced Raman scattering substrate assembly 100 or
200 can be adapted to collect and subsequently detect an analyte
that is in any one of the gaseous phase, liquid phase, or solid
phase. To that end, etched fiber base 102 or 202 having metallic
nanoparticle 104 or 204 disposed thereon can be disposed in a
gaseous phase, a liquid phase, or a solid phase. In some
embodiments, substrate assembly 100 or 200 can be disposed in all
three phases or any two of the three phases simultaneously. For
example, a first region of etched fiber base 102 or 202 can be
located in a gaseous phase, a second region of etched fiber base
102 or 202 can be located in a liquid phase (e.g., in an organic
liquid phase, in an aqueous liquid phase, or both), and a third
region of etched fiber base 102 or 202 can be located in a solid
phase. According to some embodiments, each region of etched fiber
base 102 or 202 can be specifically configured for collection of
analytes in a specific phase. Disposing etched fiber base 102 or
202 across multiple phases can allow for simultaneous collection of
analytes on etched fiber base 102 or 202 across those phases.
[0047] After the analyte or analytes are collected on etched fiber
base 102 or 202, etched fiber base 102 or 202 can be removed for
detection of the analyte or analytes by SERS. Alternatively, SERS
can be carried out in situ if, for example, substrate assembly 100
or 200 is configured to allow electromagnetic radiation to interact
with etched fiber base 102 or 202.
[0048] As an example, as shown in FIG. 1, etched fiber base 102 or
202 having metallic nanoparticle 104 or 204 disposed thereon is
placed in a sealed environment and is disposed within a gaseous
medium. Analytes of interest are collected on etched fiber base 102
or 202. Etched fiber base 102 or 202 can then be analyzed via SERS
either by removing etched fiber base 102 or 202 from needle 106 or
206, or as mentioned above, in some cases can be analyzed through
assembly 100 or 200 if the vial is transparent to electromagnetic
radiation.
[0049] Surface enhanced Raman scattering substrate assembly 100 or
200 can be used in conjunction with many different types of
analytes. Suitable examples of mediums include a food, a beverage,
a plant, an animal, or a mixture thereof. Suitable examples of food
include a vegetable, a fruit, a meat, a dairy product, a grain, and
mixtures thereof. Suitable examples of beverages include milk,
beer, wine, water, juice, coffee, tea, and mixtures thereof. In
still further embodiments, the medium can be generated from a
living organism. For example, the medium can be living organism's
breath. In some embodiments, the medium, and therefore the analyte,
can be heated to put the analyte into a gaseous phase for
detection.
[0050] The analyte can be any analyte of interest. For example, the
analyte can be a pesticide, a metabolite, a pathogen, a bacteria, a
fungi, a virus, an enzyme, a reactive oxygen species, and a mixture
thereof. Examples of a suitable pesticide is O-Ethyl S-phenyl
ethylphosphonodithioate (fonofos), thiabendazole, acetamiprid,
(iron tris(dimethyldithiocarbamate) (ferbam), phosmet, phorate,
isocarbophos, and mixtures thereof. Examples of suitable
metabolites include salicylic acid, phytoalexin, sulfonic acid,
diphenyl sulfide, allyl methyl sulfide, and a mixture thereof. In
general, any compound including sulfur may be an analyte of
interest. Examples of a suitable enzyme include an enzyme including
adenine (e.g., flavin adenine dinucleotide), nicotinamide adenine
dinucleotide phosphate oxidase. Suitable bacteria for examination
may include a gram-positive bacteria, a gram-negative bacteria, and
mixtures thereof. In some embodiments, the bacteria is chosen from
Clostridium botulinum, Listeria monocytogenes, Acetic acid
bacteria, Acidaminococcus, Acinetobacter baumannii, Agrobacterium
tumefaciens, Akkermansia muciniphila, Anaerobiospirillum,
Anaerolinea thermolimosa, Anaerolinea thermophila, Arcobacter,
Arcobacter skirrowii, Armatimonas rosea, Azotobacter salinestris,
Bacteroides, Bacteroides fragilis, Bacteroides ureolyticus,
Bacteroidetes, Bartonella japonica, Bartonella koehlerae,
Bartonella taylorii, Bdellovibrio, Brachyspira, Bradyrhizobium
japonicum, Caldilinea aerophile, Cardiobacterium hominis,
Chaperone-Usher fimbriae, Christensenella, Chthonomonas
calidirosea, Coxiella burnetiid, Cyanobacteria, Cytophaga,
Dehalogenimonas lykanthroporepellens, Desulfurobacterium
atlanticum, Devosia pacifica, Devosia psychrophila, Devosia soli,
Devosia subaequoris, Devosia submarina, Devosia yakushimensis,
Dialister, Dictyoglomus thermophilum, Enterobacter, Enterobacter
cloacae, Enterobacter cowanii, Enterobacteriaceae,
Enterobacteriales, Escherichia, Escherichia coli, Escherichia
fergusonii, Escherichia hermannii, Fimbriimonas ginsengisoli,
Flavobacterium, Flavobacterium akiainvivens, Francisella novicida,
Fusobacterium necrophorum, Fusobacterium nucleatum, Fusobacterium
polymorphum, Haemophilus felis, Haemophilus haemolyticus,
Haemophilus influenzae, Haemophilus pittmaniae, Helicobacter,
Kingella kingae, Klebsiella pneumoniae, Kluyvera ascorbate,
Kluyvera cryocrescens, Legionella, Legionella clemsonensis,
Legionella pneumophila, Leptonema illini, Leptotrichia buccalis,
Levilinea saccharolytica, Luteimonas aquatic, Luteimonas composti,
Luteimonas lutimaris, Luteimonas marina, Luteimonas mephitis,
Luteimonas vadose, Megamonas, Megasphaera, Meiothermus, Meiothermus
timidus, Methylobacterium fujisawaense, Morax Axenfeld
diplobacilli, Moraxella, Moraxella bovis, Moraxella osloensis,
Morganella morganii, Mycoplasma spumans, Neisseria cinereal,
Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria
polysaccharea, Neisseria sicca, Nitrosomonas eutropha, Nitrosomonas
halophila, Nonpathogenic organisms, OMPdb, Pectinatus, Pedobacter
heparinus, Pelosinus, Propionispora, Proteobacteria, Proteus
mirabilis, Proteus penneri, Pseudomonas, Pseudomonas aeruginosa,
Pseudomonas luteola, Pseudoxanthomonas broegbernensis,
Pseudoxanthomonas japonensis, Rickettsia rickettsia, Salinibacter
ruber, Salmonella, Salmonella bongori, Salmonella enterica,
Samsonia, Selenomonadales, Serratia marcescens, Shigella,
Shimwellia, Solobacterium moorei, Sorangium cellulosum,
Sphaerotilus natans, Sphingomonas gei, Spirochaeta,
Spirochaetaceae, Sporomusa, Stenotrophomonas, Stenotrophomonas
nitritireducens, Thermotoga neapolitana, Thorselliaceae, Trimeric
autotransporter adhesion, Vampirococcus, Verminephrobacter, Vibrio
adaptatus, Vibrio azasii, Vibrio campbellii, Vibrio cholerae,
Victivallis vadensis, Vitreoscilla, Wolbachia, Yersiniaceae,
Zymophilus, strains thereof, and mixtures thereof.
[0051] Detection of any analyte can be used to assess many
parameters of a medium. For example, the presence of pesticides can
be used to determine whether food is safe for consumption.
Detection of certain analytes can be used to generate a profile of
a medium. For example, a medium such as wine can be analyzed for
certain analytes that can be used to grade wine using artificial
analysis. This can be used to perform a uniform analysis of the
wine having the subjectivity of a human wine tester removed. As a
further example the medium can be a person's breath. The breath can
be analyzed for certain analytes that may be indicators of bad
breath or certain health issues. Furthermore, the presence of
certain analytes such as metabolites can be indicators of biotic
stress in a plant. This can be monitored continuously to assess the
health of a plant.
[0052] Surface enhanced Raman scattering substrate assembly 100 or
200 can be manufactured in many suitable manners. For example, a
fiber can be etched to form etched fiber base 102 or 202. As
described herein, the fiber can be etched with a laser or by
exposing the fiber to an etchant. The etchant can be an acid such
as hydrochloric acid.
[0053] Following etching, the metallic nanoparticles are coated on
the surface of etched fiber base 102 or 202. Coating can be
accomplished by at least partially immersing etched fiber base 102
in a solution comprising the metal of the metallic nanoparticle.
The metal in the solution is then reduced thereon. In some
embodiments in which metallic nanoparticle layer 104 or 204
includes gold nanoparticles, the solution comprising the metal can
be HAuCl.sub.4.
[0054] In general, the assemblies 100, 200, disclosed herein allow
for analysis of target compounds (analytes) in complex mediums such
as food or biological samples without complex sampling methods. An
in-situ micro-extraction device used with a SERS needle can improve
sensitivity to analytes with minimally invasive techniques.
EXAMPLES
[0055] Various embodiments of the present disclosure can be better
understood by reference to the following Examples which are offered
by way of illustration. The present disclosure is not limited to
the Examples given herein.
Example 1
[0056] In this Example, a highly sensitive surface enhanced Raman
scattering method coupled with headspace and solid phase
micro-extraction (SPME) to detect volatile pesticide fonofos using
an etched fiber having a metallic nanoparticle coating disposed
thereon is described. Fonofos, or O-ethyl S-phenyl
ethylphosphonodithiolate, is selected as a model for detection
using this method because of its volatility (i.e., boiling point is
130.degree. C. at 0.1 mm Hg). It is one of the organophosphate soil
insecticides that can control pests such as corn rootworms.
According to Environmental Protection Agency regulatory document,
the oral exposure to fonofos can induce acethylcholinesterase
inhibition and cause acute toxicity. The chronic reference dose for
fonofos is 0.002 mg/kg/day, the health reference level is 10 ppb,
and the minimum reporting level is 0.5 ppb. A gold-nanoparticle
coated fiber was fabricated using a chemical etching and coating
method. The characterization of the fabricated fibers and their
performance in headspace-SPME and dip-SPME methods followed by SERS
analysis were determined in water and complex matrix (i.e. apple
juice).
[0057] Materials. Analytical grade standard of fonofos (>99.9%),
hydrogen tetrachloroaurate hydrate (99.999%), and sodium chloride
(>99.5%) were procured from Sigma Aldrich (St. Louis, Mo., USA).
Hydrochloric acid (34%-37.5%), Acetonitrile (99.9%), ethanol (100%)
and methanol (99.9%) were purchased from Fisher Scientific (Fair
Lawn, N.J., USA). The Langres.RTM. apple juice was purchased from
local Stop & Shop supermarket (Amherst, Mass., USA). The
stainless-steel wire (SUS304, .phi.140 .mu.m) was purchased from
the Small Parts, Inc. Stock solution of fonofos was prepared in
acetonitrile at 100 ppm and further diluted by distilled water or
apple juice.
[0058] Preparation of gold nanoparticles-coated fibers. An acid
etching reaction was used to increase the roughness of a wire fiber
as well as strengthen the binding between the gold-nanoparticles
coating and the porous stainless wire with the increased surface.
The stainless-steel wire (5 cm) was washed with methanol, ethanol
and distilled water in an ultrasonic bath for 10 min respectively
and then chemically etched in hydrochloric acid (37.5%) to create
the roughness of the wire fiber. The etched fiber was washed again
with methanol and distilled water in the ultrasonic bath for 5 min
respectively, then dried at 60.degree. C. The etched fiber was then
immersed into HAuCl.sub.4 solution (0.05%, w/w) to introduce gold
to its porous surface as demonstrated in FIG. 3. The coating
reaction is the replacement reaction between iron and gold that is
shown below.
Fe+[AuCl.sub.4].sup.-=Fe.sup.3++Au+4Cl.sup.-
The surface morphology of acid-etched fiber and gold-nanoparticles
coated fiber were characterized under microscopes and SEM.
[0059] Detection of pesticides using headspace-SPME and dip-SPME
methods. Each test pesticide stock solution of 100 mg/L (ppm) was
prepared with acetonitrile and further diluted to needed
concentrations (0.5 ppm to 0.005 ppm) with distilled water or apple
juice prior to use. 5 mL of working solution was mixed with 3 mL of
20% sodium chloride solution in a 16-mL vial with an open top
polypropylene closure and PTFE/silicone septa. The addition of 20%
NaCl solution can increase the ionic strengths and thus decreases
the solubility of organic analytes in the aqueous phase in
headspace-SPME detection. In the headspace-SPME method, the fiber
was inserted through the silicon septum into the headspace above
the working solution to extract the volatile compounds. The
extraction condition was 75.degree. C. for 30 min. After
extraction, the fiber was fixed on a slide for SERS analysis. In
the dip-SPME detection, working solution remains the same while the
fiber dipped into the working solution without salt for 30 min
under room temperature. The fiber was then air-dried and measured
using Raman microscopy.
[0060] Instruments and data analysis. The surface morphology of
etched fiber and gold-nanoparticles coated fiber were characterized
by FEI Magellan 400 scanning electron microscope (SEM, Hillsboro,
Oreg.) with the voltage of 5.0 kV.
[0061] A DXR Raman microscope (Thermo Fisher Scientific, Madison,
Wis., U.S.A.) with a 780 nm laser and a 50.times. confocal
microscope objective (0.8 mm spot diameter and 2 cm.sup.-1 spectral
resolution) was used in this study. Each spectrum was scanned from
2000 to 800 cm.sup.-1 with 1 mW laser power and a 50 mm slit width
for 2 seconds integration time. OMNIC.TM. software version 9.1 was
used to control the Raman instrument. Fifteen scans were selected
from each fiber and then averaged by the software.
[0062] The Raman spectra were analyzed using Thermo Scientific TQ
Analyst 8.0 software. All Raman intensities were calculated from at
least three replicates and standard deviations were recorded. The
peak at 1571 cm.sup.-1 Raman shift of fonofos was chosen for
further characteristic analysis due to its good consistency and
least interference with the AuNPs background and apple juice
signals.
[0063] Characterization of fiber substrate and fonofos SERS
spectra. The etched fiber has rough surface as shown in FIG. 4A to
4D. After replacement reaction, the coated fiber showed golden
color which indicates the successful coating of Au in FIG. 4E and
FIG. 4F. Under SEM, the nanoparticles were at around 100 nm and
evenly and densely distributed in FIG. 4G and FIG. 4H. This
fabrication method shows great advantage as a simple and rapid way
for coating nanoparticles onto a stainless-steel fiber comparing to
other fabrication methods including laser ablation, annealing and
chemical reaction layer by layer.
[0064] After the fiber was fabricated, its SERS-active capability
and extraction efficiency were tested in 1 ppm fonofos water
solution with dip and headspace methods. In headspace-SPME
approach, 20% NaCl solution was added to the sample as the addition
of salt usually increases the ionic strengths and decreases the
solubility of organic analytes in the aqueous phase. From FIG. 5,
the fiber has minimal background noise between 800 to 2000 cm'
Raman shift, providing no interference to pesticide signals. In dip
and headspace tests, the four most obvious peaks of fonofos on
1001, 1024, 1081 and 1576 cm.sup.-1 Raman shift were observed and
characterized in FIG. 5. The peak at 1576 cm.sup.-1 is attributed
to .nu.(C.dbd.C)phenyl stretch which is used for quantitative
analysis later. The peaks at 1081, 1024 and 1001 cm' are
respectively attributed to .nu.(S--C phenyl)+.delta.(C--H)phenyl,
.delta.(C--H)phenyl+.nu.(S--C phenyl), and .delta.(CCC)phenyl (20).
Moreover, headspace method presents higher intensity of signals and
minimal interference compared to dip method, indicating the
advantage and feasibility of headspace approach for fonofos
detection.
[0065] To investigate the sensitivity and quantitative reliability
of the method, the headspace-SPME-SERS were applied to detect
fonofos of various concentrations (0.005 ppm to 0.5 ppm) in water
as shown FIG. 6A. The lowest detectable concentration at 5 ppb
(0.005 ppm) was reached. Current SERS studies in detecting fonofos
report higher detectable concentration at 10 ppm, and their limit
of detection ranges from 0.1 ppm to 1 ppm. In comparison, the
disclosed method offers a huge improvement on sensitivity due to
the use of the headspace method for capturing volatile fonofos.
Peak intensity at 1576 cm.sup.-1 was selected for quantitative
analysis and the linear range was obtained from 0.025 ppm to 0.5
ppm in FIG. 6B. Fonofos concentration and Raman intensity present a
nice linear relation with coefficient of determination (R.sup.2) as
0.9883. The Limit of Detection (LOD) value was calculated to be
0.0052 ppm according to the equation of 3.3 .sigma./S, where
.sigma. is the standard deviation of the blank, and S is the slope
of the calibration curve. The LOD value is confirmed by the
detection of 0.005 ppm (5 ppb) fonofos in FIG. 6A. The theoretical
Limit of Quantification (LOQ) value can be extended to 0.015 ppm
according to the equation of 10 .sigma./S. Yet, the error bars
revealed that the method had large variations that needs to be
further reduced. The variation may come from varied sizes and
aggregations of the gold-nanoparticles on the fiber which may be
improved by using a stainless wire fiber with a higher quality and
purity and further optimizing the coating reaction conditions.
[0066] To further illustrate the advantage of headspace method in
detecting a volatile pesticide in a real matrix, the headspace
method was applied and compared with the dip method to detect
fonofos in apple juice. From FIG. 7A, the dip-SPME-SERS method
detected 50 ppb fonofos spiked in apple juice and cannot detect
lower concentration at 10 ppb because it was affected by the
inferencing compounds from apple juice. On the other hand,
headspace-SPME-SERS detected 5 ppb fonofos spiked in apple juice
(FIG. 7B). This data demonstrates the headspace method is more
sensitive and effective than the dip method when detecting fonofos
in complex matrices. It is because in the headspace, only volatile
compounds occupy the space and have the chance to bind to the
fiber. While in the dip detection, other components from the sample
matrix may bind to the fiber and cause interference. The lowest
detectable concentration at 5 ppb in a food sample is comparable to
the nano-liquid chromatography and the common GC method in complex
samples detection, which are 5.3 ppb and 30 ppb, respectively.
Example 2
[0067] SERS techniques were applied to monitor plant metabolites
and physiological changes to provide insight into biochemical plant
responses to biotic stress. The study was used to monitor SERS
signals of salicylic acid (SA), nicotinamide adenine dinucleotide
phosphate oxidase (NADPH oxidase), and camalexin. Each molecule is
SERS sensitive and each SERS fingerprint is different based on
their chemical structures. This allows for sensitive and selective
monitoring of response signals in plant matrixes without overlap in
spectral analyses. The presence of NADPH oxidase is also associated
with reactive oxide species (ROS) and SA and emerges rapidly within
a host. NADPH oxidase and SERS analyses allow for detection of
plant responses to biotic stress within minutes. The presence of
camalexin specifically indicates a plant response to biotic stress
and this relationship can be assessed using SERS.
[0068] Tomato plant (Solanum lycopersicum) was fostered as a model.
Fusarium proliferatum, a common tomato plant pathogen, was
administered onto the surface of the plant tissues. The plant
response was monitored in real-time in-situ locally and
systemically with a field-based portable Raman instrument. SERS
detection was performed by adding penetrable Gold nanoparticles
(AuNPs) onto the surface of leaves or flowers. On fruits, a smart
`SERS needle` device was utilized which is composed of a real
clinical needle and an inserted AuNPs coated fiber. SERS detection
can be carried out by removing the fiber from the plant tissue for
fiber-based collections of SERS spectra. The SERS needle device
also allows for the injection of biotic stress factors directly
into the fruit using a syringe wherein it is possible to monitor
biomolecular stress responses in real-time locally or
systemically.
Example 3
[0069] To analyze a person's breath a straw was inserted into a
vial, with the gold-nanoparticles coated fiber put inside the
straw. This assembly is shown in FIG. 8. Three individuals were
asked to blow in the straw for 1 minute. Then the straw was folded
to seal the breathing gas, and the fiber could be fully exposed to
the gas. After 5 minutes of exposure and extraction, the fiber was
measured with Raman scattering with 5 mW laser power. Resulting
spectra are shown in FIG. 9.
Example 4
[0070] To detect the presence of an analyte such as a pesticide in
food a surface enhanced Raman scattering substrate assembly was
placed partially within a tomato. This is schematically shown in
FIG. 10. As shown in FIG. 10, the needle is positioned within a
solid phase, liquid phase, and gaseous (e.g., headspace) phase of
the tomato.
[0071] 100 ppm of the pesticide thiabendazole was injected on one
side of the tomato. The pesticide was left to translocate through
the tomato for a time period of 48 hours. After 48 hours, the
surface enhanced Raman scattering substrate was used to detect the
presence of the pesticide in the tomato. Detection was performed
across the solid, liquid, and gaseous phases although detection can
be optionally limited to any one phase of sub-combination of
phases. FIG. 11 is a spectrum showing the presence of thiabendazole
in the tomato.
Example 5
[0072] In Example 5, an in-situ filter was synthesized in a needle
via in-situ polymerization using a high internal phase emulsion
(HIPE) technique. First, dicyclopentadiene (DCPD) was pre-mixed
with (poly(ethylene glycol)-block-poly(propylene
glycol)-block-poly(ethylene glycol (Pluronic1L-121) to create a
mixture. Then, deionized water (DI) (16 mL) was added dropwise to
the mixture under constant stirring to form high-internal phase
emulsion. A solution of
(H2IMes)(PCy3)Cl2Ru(3-phenyl-indenylid-1-ene) (M2) in toluene was
added to the solution as a catalyst.
[0073] The mixed emulsion was withdrawn into a needle shell and
cured in-situ at 80.degree. C. The cured DCPD polymer formed a
porous polymer network was used as an in-situ filter. Prior to
application, the cured HIPE filter was washed in acetone to remove
any un-cured monomers. The in-situ filter made in Example 5 can be
seen in FIG. 12. Alternative monomeric compounds could be used for
in-situ filter synthesis, such as divinylbenzene (DVB),
2-ethylhexyl acrylate (EHA) and methacrylate (EHMA), butyl acrylate
(BA) and isobornyl acrylate (IBA), methyl methacrylate (MMA), and
vinylbenzyl chloride (VBC). An etched fiber could then be inserted
into the needle with the DCPD filter for use in SERS analysis.
[0074] The terms and expressions that have been employed are used
as terms of description and not of limitation, and there is no
intention in the use of such terms and expressions of excluding any
equivalents of the features shown and described or portions
thereof, but it is recognized that various modifications are
possible within the scope of the embodiments of the present
disclosure. Thus, it should be understood that although the present
disclosure has been specifically disclosed by specific embodiments
and optional features, modification and variation of the concepts
herein disclosed may be resorted to by those of ordinary skill in
the art, and that such modifications and variations are considered
to be within the scope of embodiments of the present
disclosure.
ADDITIONAL EMBODIMENTS
[0075] The following exemplary embodiments are provided, the
numbering of which is not to be construed as designating levels of
importance:
[0076] Embodiment 1 provides a surface enhanced Raman scattering
substrate assembly for detecting an analyte, the assembly
comprising:
[0077] an etched fiber base;
[0078] a metallic nanoparticle coating disposed over at least a
portion of an external surface of the etched fiber base.
[0079] Embodiment 2 provides the assembly of Embodiment 1, wherein
the etched fiber base comprises stainless steel, copper, lead,
chromium, tin, magnesium, aluminum, zinc, manganese, calcium,
alloys thereof, and mixtures thereof.
[0080] Embodiment 3 provides the assembly of any one of Embodiments
1 or 2, wherein the etched fiber base is acid-etched.
[0081] Embodiment 4 provides the assembly of any one of Embodiments
1-3, wherein the metallic nanoparticle coating is disposed over
about 50% to about 100% of the total surface area of the etched
fiber base.
[0082] Embodiment 5 provides the assembly of any one of Embodiments
1-4, wherein the metallic nanoparticle coating is dispersed over
about 70% to about 100% of the total surface area of the etched
fiber base.
[0083] Embodiment 6 provides the assembly of any one of Embodiments
1-5, wherein the metallic nanoparticle coating is dispersed over
about 90% to about 98% of the total surface area of the etched
fiber base.
[0084] Embodiment 7 provides the assembly of any one of Embodiments
1-6, wherein a surface area of the etched fiber base is greater
than a corresponding fiber base that is free of etching.
[0085] Embodiment 8 provides the assembly of any one of Embodiments
1-7, wherein the etched fiber base has a length ranging from about
3 cm to about 6 cm.
[0086] Embodiment 9 provides the assembly of any one of Embodiments
1-8, wherein the etched fiber base has a length ranging from about
4 cm to about 5 cm.
[0087] Embodiment 10 provides the assembly of any one of
Embodiments 1-9, wherein the etched fiber base has a width ranging
from about 100 .mu.m to about 400 .mu.m.
[0088] Embodiment 11 provides the assembly of any one of
Embodiments 1-9, wherein the etched fiber base has a width ranging
from about 0.5 cm to about 5 cm.
[0089] Embodiment 12 provides the assembly of any one of
Embodiments 1-11, wherein the etched fiber base is substantially
cylindrically shaped.
[0090] Embodiment 13 provides the assembly of any one of
Embodiments 1-12, wherein the metallic nanoparticle coating
comprises a plurality of metallic nanoparticles.
[0091] Embodiment 14 provides the assembly of any one of
Embodiments 1-13, wherein each of the plurality of metallic
nanoparticles, independently comprise Ag.sub.2O, elemental silver,
elemental gold, elemental copper, elemental platinum, mixtures
thereof, alloys thereof, or combinations thereof.
[0092] Embodiment 15 provides the assembly of any one of
Embodiments 1-14, wherein each of the plurality of metallic
nanoparticles comprises elemental gold.
[0093] Embodiment 16 provides the assembly of any one of
Embodiments 1-15, wherein at least one of the plurality of metallic
nanoparticles is a nanosphere, a nanochain, a nanoreef, a nanobox,
or a nanostar.
[0094] Embodiment 17 provides the assembly of any one of
Embodiments 1-16, wherein a largest dimension of at least one of
the plurality of metallic nanoparticles has a largest dimension in
a range of from about 25 nm to about 500 nm.
[0095] Embodiment 18 provides the assembly of any one of
Embodiments 1-17, wherein a largest dimension of at least one of
the plurality of metallic nanoparticles has a largest dimension in
a range of from about 50 nm to about 100 nm.
[0096] Embodiment 19 provides the assembly of any one of
Embodiments 1-18, further comprising a metallic microparticle
coating dispersed over at least a portion of the surface of the
etched fiber base.
[0097] Embodiment 20 provides the assembly of any one of
Embodiments 1-19, further comprising a needle circumscribing at
least a portion of the fiber base.
[0098] Embodiment 21 provides the assembly of Embodiment 20,
wherein the needle comprises a metal.
[0099] Embodiment 22 provides the assembly of any one of
Embodiments 1-21, wherein the assembly is further configured to
detect the analyte in at least one of a gaseous phase, a liquid
phase and a solid phase.
[0100] Embodiment 23 provides the assembly of any one of
Embodiments 1-22, wherein the analyte is chosen from a pesticide, a
metabolite, a pathogen, a bacteria, a fungi, a virus, an enzyme, a
reactive oxygen species, and a mixture thereof.
[0101] Embodiment 24 provides the assembly of Embodiment 23,
wherein the pesticide is chosen from O-Ethyl S-phenyl
ethylphosphonodithioate, thiabendazole, acetamiprid, iron
tris(dimethyldithiocarbamate), phosmet, phorate, isocarbophos, and
mixtures thereof.
[0102] Embodiment 25 provides the assembly of Embodiment 23,
wherein the metabolite is chosen from salicylic acid, phytoalexin,
sulfonic acid, diphenyl sulfide, allyl methyl sulfide, and a
mixture thereof.
[0103] Embodiment 26 provides the assembly of Embodiment 23,
wherein the enzyme is chosen from flavin adenine dinucleotide,
nicotinamide adenine dinucleotide phosphate oxidase, and mixtures
thereof.
[0104] Embodiment 27 provides the assembly of Embodiment 23,
wherein the bacteria is chosen from a gram-positive bacteria, a
gram-negative bacteria, and mixtures thereof.
[0105] Embodiment 28 provides the assembly of Embodiment 27,
wherein the bacteria is chosen from Clostridium botulinum, Listeria
monocytogenes, Acetic acid bacteria, Acidaminococcus, Acinetobacter
baumannii, Agrobacterium tumefaciens, Akkermansia muciniphila,
Anaerobiospirillum, Anaerolinea thermolimosa, Anaerolinea
thermophila, Arcobacter, Arcobacter skirrowii, Armatimonas rosea,
Azotobacter salinestris, Bacteroides, Bacteroides fragilis,
Bacteroides ureolyticus, Bacteroidetes, Bartonella japonica,
Bartonella koehlerae, Bartonella taylorii, Bdellovibrio,
Brachyspira, Bradyrhizobium japonicum, Caldilinea aerophile,
Cardiobacterium hominis, Chaperone-Usher fimbriae, Christensenella,
Chthonomonas calidirosea, Coxiella burnetiid, Cyanobacteria,
Cytophaga, Dehalogenimonas lykanthroporepellens, Desulfurobacterium
atlanticum, Devosia pacifica, Devosia psychrophila, Devosia soli,
Devosia subaequoris, Devosia submarina, Devosia yakushimensis,
Dialister, Dictyoglomus thermophilum, Enterobacter, Enterobacter
cloacae, Enterobacter cowanii, Enterobacteriaceae,
Enterobacteriales, Escherichia, Escherichia coli, Escherichia
fergusonii, Escherichia hermannii, Fimbriimonas ginsengisoli,
Flavobacterium, Flavobacterium akiainvivens, Francisella novicida,
Fusobacterium necrophorum, Fusobacterium nucleatum, Fusobacterium
polymorphum, Haemophilus felis, Haemophilus haemolyticus,
Haemophilus influenzae, Haemophilus pittmaniae, Helicobacter,
Kingella kingae, Klebsiella pneumoniae, Kluyvera ascorbate,
Kluyvera cryocrescens, Legionella, Legionella clemsonensis,
Legionella pneumophila, Leptonema illini, Leptotrichia buccalis,
Levilinea saccharolytica, Luteimonas aquatic, Luteimonas composti,
Luteimonas lutimaris, Luteimonas marina, Luteimonas mephitis,
Luteimonas vadose, Megamonas, Megasphaera, Meiothermus, Meiothermus
timidus, Methylobacterium fujisawaense, Morax Axenfeld
diplobacilli, Moraxella, Moraxella bovis, Moraxella osloensis,
Morganella morganii, Mycoplasma spumans, Neisseria cinereal,
Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria
polysaccharea, Neisseria sicca, Nitrosomonas eutropha, Nitrosomonas
halophila, Nonpathogenic organisms, OMPdb, Pectinatus, Pedobacter
heparinus, Pelosinus, Propionispora, Proteobacteria, Proteus
mirabilis, Proteus penneri, Pseudomonas, Pseudomonas aeruginosa,
Pseudomonas luteola, Pseudoxanthomonas broegbernensis,
Pseudoxanthomonas japonensis, Rickettsia rickettsia, Salinibacter
ruber, Salmonella, Salmonella bongori, Salmonella enterica,
Samsonia, Selenomonadales, Serratia marcescens, Shigella,
Shimwellia, Solobacterium moorei, Sorangium cellulosum,
Sphaerotilus natans, Sphingomonas gei, Spirochaeta,
Spirochaetaceae, Sporomusa, Stenotrophomonas, Stenotrophomonas
nitritireducens, Thermotoga neapolitana, Thorselliaceae, Trimeric
autotransporter adhesion, Vampirococcus, Verminephrobacter, Vibrio
adaptatus, Vibrio azasii, Vibrio campbellii, Vibrio cholerae,
Victivallis vadensis, Vitreoscilla, Wolbachia, Yersiniaceae,
Zymophilus, strains thereof, and mixtures thereof.
[0106] Embodiment 29 provides the assembly of any one of
Embodiments 1-28, wherein the analyte is located in a medium.
[0107] Embodiment 30 provides the assembly of Embodiment 29,
wherein the medium comprises a food, a beverage, a plant, an
animal, or a mixture thereof.
[0108] Embodiment 31 provides the assembly of Embodiment 30,
wherein the food is chosen from a vegetable, a fruit, a meat, a
dairy product, a grain, and mixtures thereof.
[0109] Embodiment 32 provides the assembly of Embodiment 30,
wherein the beverage is chosen from milk, beer, wine, water, juice,
coffee, tea, and mixtures thereof.
[0110] Embodiment 33 provides the assembly of any one of
Embodiments 1-32, further comprising:
[0111] a source of electromagnetic radiation in optical
communication with the metallic nanoparticle coating; and
[0112] a detector for detecting a signal from the metallic
nanoparticle coating.
[0113] Embodiment 34 provides a method for detecting an analyte,
the method comprising:
[0114] contacting the etched fiber base of any one of Embodiments
1-33 with the medium of any one of Embodiments 29-33;
[0115] contacting the medium with an electromagnetic emission;
[0116] detecting the analyte; and
[0117] generating a spectrum.
[0118] Embodiment 35 provides the method of Embodiment 34, further
comprising identifying an analyte in the medium from the
spectrum.
[0119] Embodiment 36 provides the method of Embodiment 35, further
comprising quantifying an amount of analyte present in the medium
from the spectrum.
[0120] Embodiment 37 provides the method of any one of Embodiments
34-36, wherein the etched fiber base is located in at least one of
a gaseous phase, a liquid phase, or a solid phase.
[0121] Embodiment 38 provides the method of any one of Embodiments
34-37, wherein the etched fiber base and the medium are located in
a sealed environment.
[0122] Embodiment 39 provides the method of any one of Embodiments
34-38, wherein the electromagnetic emission is a laser
emission.
[0123] Embodiment 40 provides the method of any one of Embodiments
34-39, wherein the analyte is an indicator of a response to biotic
stress.
[0124] Embodiment 41 provides the method of any one of Embodiments
34-40, further comprising heating the analyte to a temperature
sufficient to put the analyte into a gaseous phase.
[0125] Embodiment 42 provides a method of making the assembly of
any one of Embodiments 1-41, the method comprising:
[0126] etching a fiber to form the etched fiber base; and
[0127] coating the metallic nanoparticles on the surface of the
etched fiber base.
[0128] Embodiment 43 provides the method of Embodiment 42, wherein
the fiber is etched by exposing the fiber to an etchant.
[0129] Embodiment 44 provides the method of Embodiment 43, wherein
the etchant is an acid.
[0130] Embodiment 45 provides the method of any one of Embodiments
43 or 44, wherein the acid is hydrochloric acid.
[0131] Embodiment 46 provides the method of any one of Embodiments
42-45, wherein coating the metallic nanoparticles on the surface of
the etched fiber base comprises at least partially immersing the
etched fiber base in a solution comprising the metal of the
metallic nanoparticle and reducing the metal in the solution.
[0132] Embodiment 47 provides the method of Embodiment 46, wherein
the solution comprises HAuCl.sub.4.
[0133] Embodiment 48 provides the assembly of Embodiment 1, further
comprising a needle circumscribing at least a portion of the fiber
base, and an in-situ filter in the needle.
[0134] Embodiment 49 provides the assembly of Embodiment 1, wherein
the in-situ filter comprises of cellulose, nitrocellulose,
polytetrafluoroethylene (PTFE), nylon, polycarbonate, acrylic based
polymers, methacrylic based polymers, and combinations thereof.
[0135] Embodiment 50 provides the assembly of Embodiment 1, wherein
the in-situ filter comprises a plurality of pores each having a
size of about 5 .mu.m to about 35 .mu.m.
[0136] Embodiment 51 provides the assembly of Embodiment 50,
wherein the in-situ filter comprises a plurality of pores each
having a size of about 10 .mu.m to about 25 .mu.m.
[0137] Embodiment 52 provides the assembly of Embodiment 1, wherein
the in-situ filter is configured to filter impurities out of the
medium.
[0138] Embodiment 53 provides the assembly of Embodiment 1, wherein
the in-situ filter is configured to prevent impurities from
reaching the fiber base.
[0139] Embodiment 54 provides the assembly of Embodiment 1, wherein
the in-situ filter is located in an end of the needle.
[0140] Embodiment 55 provides the assembly of Embodiment 1, wherein
the in-situ filter is located along the walls of the needle.
* * * * *