Electrospun nanofiber-based electro-chemical sensing system

Abstract

A method for detecting hazardous materials using an electro chemical sensor system by electrospinning a polymer solution to produce a dissolvable nanofiber mesh and collecting contaminant particles on the nanofiber mesh by exposing the nanofiber mesh to an aerosol containing contaminant particles. The electro chemical sensor system comprises an electrochemical cell connected to a potentiostat. The electrochemical cell comprises a working electrode comprised of a nanofiber membrane and a reference electrode.

Description

ELECTROSPUN NANOFIBER-BASED ELECTRO-CHEMICAL SENSING SYSTEMBACKGROUND

[0001] Indoor and outdoor air filtration systems in and around homes, businesses, hospitals manufacturing facilities and virtually any area in which humans work or live are in search of periodic or continuous sensors for the detection of airborne pathogens and / or toxic chemicals. There is a continuing global need for sensing technologies that can allow monitoring and detection of hazardous and / or toxic chemicals for work safety, occupational health, and environmental protection. Such monitoring and detection can decrease exposure and the related consequences, for example medical care and hospitalization. In addition, there is global attention to sensing technologies that can allow health monitoring (e.g. cancer biomarkers) and early diagnostics of analytical targets in food, environmental, and forensics fields.SUMMARY

[0002] Aspects of this disclosure are directed to use of electrospun nanofibers (ENF) in electro chemical sensing systems, apparatus and methods. Use of ENF provides for electro-chemical sensing systems of minimal size, weight, and power, and a cost-effective combined aerosol collection, detection and monitoring system design along with the advancement of real-time monitoring and altering capabilities. Two- and three-electrode setups are schematically represented in FIG. 3A and FIG. 3B, respectively, using electrospun nanofiber membranes as the electrodes for electrochemical sensing applications. The electrospun nanofiber (ENF) working electrode can absorb the airborne dust, pathogen, toxic gas or other contaminant in liquid, solid, and gaseous phases. The ENF two- and three -electrode setup, referred to in this document as ENF electrodes, will work with relevant electrical devices (e.g., aerosol collector, potentiostat and data acquisition devices) to measure the potential difference between working and reference electrodes. Due to size, shape, and material, ENF electrode-equipped electro-chemical sensing devices can offer low-cost, precise, sensitive, rapid, and quantitative detection of common analytical targetssuch as food, environmental, forensics, cancer biomarkers, and pathogenic monitoring and sensing agents.Electro-chemical systems using the ENF electrode configurations disclosed herein will not only have minimal size, weight, power and cost compared to currently available sensors but, in addition, can be used remotely in hazardous conditions.

[0003] Electro-chemical sensors with electrospun nanofiber electrodes differ from the current electrochemical sensors that utilize metal, ceramics, polymeric, or composite ink-based electrodes. The absorption capability and surface-to-volume ratio of electrospun nanofiber electrodes is higher than such materials, which is believed to lead to greater sensing capabilities. Additionally, it is expected that the cost, solution volume, and size of the ENF-based electrode will provide for a less-expensive, space efficient electro-chemical sensor system. Electrochemical sensors with ENF electrodes may be employed in a number of applications, including but not limited to biosensor applications, teaching laboratories, and systems that require two-or three-electrode configurations for chemical sensing.

[0004] The use of ENF electrodes for aerosol detection systems can be a better option than current aerosol detection sensors, for example, screen printed electrodes, due to its capturing efficiency, size, weight, power consumption, cost, robustness, additive manufacturing, and automatization advantages. Hie option of various sizes, porosity, and layers of different materials in ENF electrodes will overcome the potential problems associated with screen-printed electrodes or microfiber-based filters, such as absorbability, fragility, clogging, scalability, and cost.

[0005] ENF electrodes in accordance with this disclosure can be used in electro-chemical sensors, which may be two- or three-electrode sensors. A two-electrode sensor is schematically illustrated in FIG.1A and comprises a working (W) 100 and reference (R) 110 electrode, which create the two-electrode setup or a two-electrode electrochemical cell 120. A three-electrode sensor is schematically illustrated in FIG. IB and comprises a working (W) 100, reference (R) 110, and counter (C) 140 electrode, which create the three- electrode setup or a three-electrode electrochemical cell 150. A working electrode 100, also known as a research or sensing electrode, is used where the study solution is placed for a reaction to occur on the electrode. The use of a reference electrode 110 in the two-electrode setup allows for measuring the unpolarized electrode potentials, Emeas, between the reference 110 and working electrodes 100 (FIG. 2A). The working electrode 100 needs to be polarized to measure the quantitative kinetic information of the sensing system. For this purpose, a counter electrode 130 is added that yields the three-electrode setup. FIG. 2B shows the configuration of a three-electrode setup that consists of a working electrode 100, a reference electrode 110, and a counter electrode 130. Ideally, the counter electrode 130 is placed comparatively far from the position of the working electrode 100, and the reference electrode 110 is placed close to the working electrode 100. The electrochemical sensors may be connected to a multimeter 130 which measures the voltage difference created when the system is exposed to a target contaminant, pathogen, (e.g. a toxic gas) or other toxic chemical. The electro-chemical sensor functions by reacting to the target pathogen and produces an electric signal that reflects the amount of the target contaminant that exists in the medium in which the target gas exists (air. for example). Current electrochemical sensing systems utilize electrode configurations in which the electrodes are screen printed electrodes (SPE) comprised of a selected material, for example, metal, ceramics, polymeric, or composite ink-based material. Such SPEs may include carbon, silver, gold or platinum, deposited on plastic, ceramic or other known substrates.

[0006] Using current microsensor platfonns (e.g., screen printed electrodes) to detect the presence of pathogens, toxic chemicals, volatile organic compounds (VOCs) and other known contaminants can be inadequate for sensing the contaminants, a time-consuming process and such systems can be expensive. The disclosed ENF electrodes all for n electro chemical sensing system that effectively collects, detects and monitors for target contaminants, including for example airborne pathogens and toxic chemicals and overcomes the difficulties of past microsensor platforms.BRIEF DESCRIPTION OF THE FIGURES

[0007] Various aspects of the present disclosure are illustrated in the following detailed description and accompanying figures.

[0008] FIGS. 1A and IB are schematic illustrations of two and three electrode electro-chemical sensing systems.

[0009] FIGS. 2 A and 2B are additional schematic illustrations of two and three electrode setups used in electro-chemical sensing systems.

[0010] FIGS. 3A and 3B are exemplary schematic illustrations of two and three electrode setups of a specific shape that can be created by depositing nanofiber on a collector and cutting the resulted cloth.

[0011] FIG. 4 schematically shows the production and application of ENF sensors form electorspinning to a data acquisition system which can be integrated with the ENF sensors to send real time data to cloud-based loT or other computing systems to alert the presence of aerosol with contaminants.

[0012] FIG. 5A and 5B are schematic representations of production of a nanofiber with cross aligned fibers, and its subsequent use with solvent liquid containing target contaminants delivered to an electrode sensor using the electrospun nanofiber and delivered to other sensors.

[0013] FIG. 6A is an image of PCL ENF electrodes produced using the systems disclosed herein. The PCL ENF electrodes were produced by laser cut from a PCL cloth.

[0014] FIG. 6B is an image of PCL-MgO ENF electrodes produced using the systems disclosed herein. Tire PCL -Metal Oxide ENF electrodes were created by knife cut from a PCL- MgO cloth.

[0015] FIG. 7A is a scanning electron microscope (SEM) image of PCL membranes.

[0016] FIG. 7B is a scanning electron microscope (SEM) image of PCL-MgO membranes.

[0017] FIG. 8 is a schematic illustration of an electrospinning apparatus of FIG. 4.

[0018] FIG. 9 is a schematic illustration of the system of FIG. 5 A.DETAILED DESCRIPTION

[0019] Particular aspects of the present invention and / or disclosure are described in greater detail below. The terms and definitions provided herein control if in conflict with terms and / or definitions incorporated by reference.

[0020] As used herein, the terms ‘"comprises,” ‘"comprising;” or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, composition, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements notexpressly listed or inherent to such process, method, composition, article, or apparatus. The temr "exemplary" is used in the sense of “example” rather than “ideal.”

[0021] As used herein, the singular forms “a,” “an," and “the” include plural reference unless the context dictates otherwise. The terms “approximately” and “about” refer to being nearly the same as a referenced number or value. As used herein, the terms “approximately” and “about” should be understood to encompass ± 5% of a specified amount or value.

[0022] As used herein, loT stands for “internet of things” and refers to a network of devices that are connected to the internet and can exchange data with each other and other devices and systems connected to the internet.

[0023] As used herein, potentiometer is intended to mean a three -terminal variable resistor that allows for adjustable voltage division in an electrical circuit.

[0024] Tire present disclosure addresses the needs described above through the use of nanofiber membranes in electrochemical sensing systems and applications. In one aspect, the electrodes used in the systems are comprised of ENF membranes. In another aspect, ENF membranes are used to collect target contaminants contained in aerosols or other mediums. The membranes are dissolvable, so that the resulting liquid can be brought into contact with the electrodes in an electrochemical sensing system. One aspect of the disclosure is the use of an electro chemical sensor to detect aerosolized pathogens and toxic gases.

[0025] In some aspects, this disclosure is directed to the production of two- or three-electrode electro-chemical sensors in which the electrodes are conductive polymer composites comprised ofconductive nanofiber and nanoparticles completely or partially laminated by thennoplastic polymer films. Single or composite electrospun nanofiber-based two-electrode (FIG. 3A) and three-electrode (FIG. 3B) systems 300 can be manufactured with electrospun nanofiber deposited on substrates and cut in a specific design architecture. A nanofiber electrospinning system can be used to produce the laminated or without laminated conductive polymer. Upon creating the nanofiber membrane, polymer cutting techniques (e.g., knife, laser, die, ultrasonic, wire electrical discharge machining) can be utilized to generate the desired electrode shapes. FIG. 3A and FIG. 3B show examples of different shapes that can be created from the membrane. The electrode designs in FIGS. 3A and 3B resemble the shapes of typical screen-printed electrodes (SPEs).

[0026] As will be further explained below7, a nanofiber membrane may be comprised of a conductive composite polymer solution ejected from an infusion pump glass syringe via a charged needle from a high-voltage power source. A wide range of high voltage may be used in an electrospinning setup (5-40 KV) for different nanofiber matrix production, 9 KV for PCL-based fiber matrix. The tip-to-collector distance is varied for fiber collection by controlling the solution feeding rate. The fiber mats deposit on a grounded collector. Typically, samples are prepared at room temperature. The nanofiber matrix obtained from electrospinning is dried to remove the residual solvent. Hie nanofiber membrane may be cut into a small piece.

[0027] Referring to FIGS. 4 and 8, a typical electrospinning system can contain a syringe 803 (plastic / glass), metallic needle 550„ high-power voltage supply 560 (0-50 kV, as seen in FIG. 5A), a collector 815 (drum, parallel wire / disc, flat plate), and a syringe pump 530. The high voltage pow7er issupplied between the needle tip and the collector, the positive electrode being connected to the needle tip and the ground connected to the collector 815 More than 5 kV is usually applied, but this can vary’ depending upon the characteristics of the polymer solution. This electric voltage causes evaporation of the solvent and tends to alter the stability of the solution by charging the solution, and then repulsing action takes place. This would force the solution to enter a bending stage by stretching the solution jet. A collector 815 can collect the fiber deposited in different forms. The collector 815 can be a rotating drum or a set of parallel plate electrodes depending upon the applications of the fiber.

[0028] Representative drawings of the electrospinning system shown in FIG. 4A are seen in FIG. 8. Multilayers of fibers can be deposited on a drum collector 815 automatically using a micro relay controller 801, where the first layer material is different from the second layer. Micro relay controller 801 can alternatively power on / off syringes 803 and 805 producing the alternating polymer layers from media# 1 807 and media#2 809. For example, two motors in the syringe pump that can be operated by the micro relay controlled on / off switch to flow alterative solution passing through the charged needle during the electrospinning process. If desired, at least one of the medias may include conductive nanoparticles, for example graphite, silver, nickel, copper and / or gold. If both have conductive nanoparticles, the particles can be different types of conductive nanoparticle. Also, the polymer of each media can be different or the same. The media from syringes 803 or 805, is introduced into electrospin apparatus 811 and the resulting nanofiber 813 is collected on drum collector 815. It will be realized that the system can also be used to produce a mesh out of single media as opposed to two differing media. It is also understood that nanofiber can be produced using only one syringe.

[0029] In one embodiment, polycaprolactone (PCL)-metal oxide nanofibers may be used to create the nanofiber membrane 410. The PCL may be seeded with metal-oxide nanoparticles which may in one embodiment be MgO. Other metal oxides such as ZnO, TiO;. Zeolite, and Metal-organic frameworks (MOFs) may also be used. The addition of tire metal oxide nanoparticles will aid in the absorption qualities of the produced nanofibers. Using the custom-made electrospun nanofiber production unit, various porosities of PCL nanofiber cloths, or membranes 410 are produced (Fig. 4). The membrane 410 of FIG. 4 can be cut to a specific shape to act as an electrochemical sensor's working 100, reference 110 and counter electrodes 140 (FIG. 3A and 3B). The membrane 410 may be cut using known techniques, such as for example razor or laser cutting. Hie composite fibrous working ENF electrode will absorb or otherwise collect the aerosolized pathogen and toxic gases when an aerosol passes through the nanofiber membrane 410. This chemical absorbance in the working electrode 100 will change the voltage (electrode potential) between the working 100 and reference electrode 110. FIGS. 6A and 6B show PCL and PCL-metal oxide ENF electrodes respectively produced with the system of FIG 4. Tire PCL ENF electrodes, which may include conductive nanoparticles as described above, were produced by laser cutting from a PCL membrane and the PCL-Metal Oxide ENF electrodes were created by knife cut from a PCL-Metal Oxide membrane. Scanning electron microscope (SEM) images of the PCL and PCL-metal oxide membranes are shown in FIGS. 7 A and 7B.

[0030] An ENF electrode cartridge 420 (containing the ENF electrode) can be used with and / or in an aerosol collector 430 such that the ENF electrode cartridge 420 is in communicated with the inlet port of an aerosol collector 430 as shown in FIG. 4. The electrode cartridge 420 will provide for aerosol to bedelivered through port 422 to only the working electrode 100 comprised of the nanofiber membrane 410.The aerosol collector 430 serves the purpose of gathering and concentrating aerosol particles or molecules present in the air or gas streams. The electro-chemical system with ENF working 100, reference 110 and counter electrodes 140 will analyze and detect aerosol particles or molecules of the target pathogen or other contaminant in the air or other gas streams.

[0031] The potentiostat 160 applies a controlled potential (voltage) between the working electrode 100 and the reference electrode 110, which allows the study of the electrochemical reactions, the measurement of the redox potential, and the detection of analytes in solution based on their electrochemical properties. A data acquisition system 440 can be connected to record the electrical signals generated during the electrochemical measurements. The electrochemical sensors can be integrated with loT devices 450 via the data acquisition system 440 to send real-time sensor data from the aerosol sampler to a cloud-based computing system to monitor and alert users.

[0032] In another embodiment, depicted in FIG. 5A and FIG. 9, single or multiple layers (variable thickness) of highly water-soluble nanofiber-based filter 410 assembled in a cartridge 590 may be used to capture aerosol bioparticles, such as bacteria, viruses, pollen fungal spores, VOCs and other chemicals or pathogens. Such filters 410 designed to capture such particles and chemicals may have pore sizes configured to capture the desired particles and may be for example in the range of about 0.2 to about 5 micrometers to capture bioaerosols while allowing air to pass through with minimum airflow resistance.

[0033] FIG. 5 A shows the production of a nanofiber membrane. Drawings representative of the of the FIG. 5 A system used to produce the membrane are shown in FIG. 9. FIG. 9 illustrates production of abi-directional fiber mesh. The produced nanofiber 913 can be deposited so as to produce a bi-direction fiber mesh. The fibers can be deposited on a collector 917 automatically using a micro relay controller 919, where the direction of fiber collection is ~90° between two adjacent layers. Two sets of parallel plates 921 and 923 can be charged in an alternating period to produce bi-direction fiber mesh. When one set of parallel plates is charged, the other set is uncharged and vice versa. In doing so, the bidirectional fibers are deposited on the collector 917.

[0034] A filter cartridge for a collector (ENF Aerosol Collector), as shown in FIG. 5A, may be produced to capture aerosol with contaminants therein (e g., dust, pathogens, and VOCs) to collect particles. Tire nanofiber membrane 410 produced as shown in FIG. 5 A is placed in the filter cartridge 590. The filter cartridge 590 is placed in an aerosol collector 430, and the aerosol (pathogen or VOCs) is passed into and through the filter cartridge 590 in the aerosol collector 430 and the aerosol is collected on the nanofiber membrane 410. The nanofiber membrane 410 will be dissolved in an aqueous solution by shaking or centrifuging the solution. The cartridge 590 will be removed after the dissolve of the nanofiber membrane 410. The dissolved solution, along with the contaminants that were captured by the nanofiber membrane 410 can then be deposited on the working electrode 100 of two or three electrode electrochemical cells which may comprise the electrospun nanofiber electrodes as described herein, or screen-printed electrode (SPE) technologies. Thus, in the embodiment of FIG. 5A, the electrodes may be those typically used in the current art, for example, screen printed electrodes of a selected material, for example, graphene-based conductive PEDOT: PSS(G-PEDOT: PSS) and Polyaniline(G-PANI) inks. The electrodes may be printed on plastic, ceramic or other known substrates. The electrodes will be connected to a potentiostat 160, andthe target contaminant will generate a voltage differential from which the amount of contaminant can be determined. Detection is enabled by the electrodes (FIG. 5A) by functionalizing tire electrode surface with specific recognition elements, including antibodies, aptamers, and peptides, for bacteria detection in water. The interaction between aerosol particles and the recognition elements generates the electrical signal that will be measured using electrochemical techniques, allowing for sensitive and selective aerosolized bacteria detection.

[0035] In the embodiment of FIGS. 5 A polyvinyl alcohol (PVA) nanofibers may be used to create the nanofiber membrane 410. PVA nanofiber material dissolves rapidly in water (generally within 2 minutes) without being influenced by aerosol particle properties (size, shape, and charge). For example, PVA powder (Sigma- Aldrich) will be mixed with deionized water with a 10 wt% of PVA concentration. The mixture will be stirred on a thermal magnetic stirrer for 5 hr. at 80°C. As shown in FIG. 5A, and in FIG. 9 two sets of parallel plates will be charged in an alternating period using a micro relayed programmed on / off switch to produce fiber cloth where the direction of fiber collection is -90° between two adjacent layers. Greater detail of the fabrication process is given in U.S. Patent Application No. 18 / 209.190. A knife punch or laser engraver will cut a PVA disc from the resulting cloth. The PVA nanofiber membrane 410 will dissolve as described, and captured particles can be delivered to downstream devices (e.g. electrode sensors, potentiostats and data acquisition systems) for analysis.

[0036] Tire systems, apparatus and methods disclosed herein include in one embodiment the use of unique ENF electrodes to detect aerosolized pathogens and toxic chemicals by absorbing, filtering, and sensing. The novel ENF-electrodes systems integrate three components: (1) a unique aerosolized pathogenand toxic chemical absorbing ENF electrode configuration, (2) a reusable and variable size device for holding the ENF electrodes and detecting the presence of the aerosolized pathogen and toxic chemical with the use of an aerosol collector 430, and (3) an loT platform 450 assembled with tire ENF electrode system for reporting and alarming the aerosolized pathogen and toxic chemical presence remotely.

[0037] The systems, apparatus and methods disclosed herein include a highly hydrolyzed electrospun nanofiber filtration membrane 410 to pull aerosol particles from the air using an aerosol collector 430 and transfer the membrane 410 into a solvent via a filter cartridge 590 for integration and detection using. A filter cartridge 590, which may be a 3D-printed filter cartridge may be used to hold electrospun polyvinyl alcohol (PVA), the best water-soluble polymer, nanofiber membrane with a specific size, porosity, and thickness for an aerosol collector. PVA cross-direction and aligned nanofiber will be produced by patent pending electrospinning technique (non-provisional U.S. Patent Application No. 18 / 209,190). The PVA membrane will capture aerosol particles when installed in an aerosol collector 430 device and deliver to solution. The solution may be poured on to electrodes, which may be for example the ENF electrodes described herein, or SPE electrodes, will generate a voltage differential as described herein to allow the detection and reporting of contaminants in the captured aerosol.

[0038] Nanofiber-based aerosol collection can be a better option than other aerosol collectors due to its capturing efficiency, size, weight, power consumption, cost, robustness, additive manufacturing, and scaling advantages. The collector may use PCL and PVA-based nanofibers without being influenced by aerosol particle properties (size, shape, and charge). Tire PCL-metal oxide based ENF working electrode in one embodiment can capture the toxic chemicals. In another embodiment, PVA nanofiber membrane candeliver the captured particles to downstream devices for analysis using microsensor platforms . It is believed that electrospun nanofiber-based particle filters have the highest airborne particle collection efficiency compared to other filtration materials. In addition, nanofiber-based filters can be produced in variable sizes and porosity, capturing defense-relevant size ranges (typically between 0.1 and 10 micrometers (pm)).

[0039] The method and apparatus of ENF electrode systems (FIG. 4 and FIG. 5) for detecting aerosolized pathogens and toxic chemicals are innovative and have commercial values, for example; the ability to collect different particle sizes by varying the nanofiber membrane morphology, e.g., porosity in the filters and integration with the ENF electrodes, the ability to capture and detect particles in varying volumes of different aerosol by varying filter design of working electrodes in filter cartridges, the ability to utilize electrospun nanofiber (patented or patent pending) and additive manufacturing technologies for filter and electrode cartridge design for the system, the ability to use microcontroller software to operate the electrodes, detect aerosolized pathogens and toxic chemicals and report via loT without manual intervention, and the ability to integrate the above system with an unmanned aerial vehicle (UAV) due to their minimal size, weight, power and cost for collecting aerosol samples remotely in hazardous conditions.

[0040] This disclosure can be further understood by reference to the following numbered aspects, which are exemplary.

[0041] Aspect 1: A method comprising: electrospinning a polymer solution so as to produce a dissolvable nanofiber mesh;exposing the nanofiber mesh to an aerosol containing contaminant particles; and collecting the contaminant particles on the nanofiber mesh.

[0042] Aspect 2: The method of Aspect 1, further comprising: dissolving the nanofiber mesh with the collected particles in an aqueous solution to create a solution: contacting an electrochemical cell with the solution; and using a potentiostat connected to the electrochemical cell to detennine the amount of contaminant in the aerosol.

[0043] Aspect 3: The method of Aspect 1 or Aspect 2, further comprising using an loT connected to the electrochemical cell to monitor or alter the presence of contaminants in the aerosol.

[0044] Aspect 4: The method of any of Aspects 1 to 3, further comprising monitoring the contaminant in the aerosol remotely in hazardous conditions.

[0045] Aspect 5 : The method of any preceding Aspect, wherein the nanofiber membrane comprises an electrostatic polymer in combination with conductive metal nanoparticles, metal oxide nanoparticles or mixtures thereof.

[0046] Aspect 6: The method of Aspect 5, wherein the nanofiber mesh contains conductive nanoparticles, the method further comprising: creating an electrochemical cell with the conductive particle containing nanofiber mesh;exposing the electrochemical cell to an aerosol containing a target contaminant; and using a potentiostat connected to the electrochemical cell to determine the amount of target contaminant in the aerosol.

[0047] Aspect 7 : The method of any preceding Aspect, wherein the electrochemical cell is a microsensor platform selected from the group consisting of a microfluidic optical particle analyzer, a microPCR and a screen-printed electrode.

[0048] Aspect 8: The method of Aspect 7, wherein the electrochemical cell is comprised of at least two electrodes.

[0049] Aspect 9: The method of Aspect 8, wherein the electrochemical cell is comprised of a nanofiber membrane.

[0050] Aspect 10: The method of any of proceeding Aspect, wherein the polymer material is selected from the group consisting of PVA, PVP or composite of PVA-PVP.

[0051] Aspect 11 : An electro chemical sensor system comprising: a potentiostat; and an electrochemical cell connected to the potentiostat, the electrochemical cell comprising at least a working electrode and a reference electrode, wherein at least the working electrode is comprised of a nanofiber membrane.

[0052] Aspect 12: The electro chemical sensor system of Aspect 11, wherein the nanofibermembrane is electrospun.

[0053] Aspect 13: The electro chemical sensor system of Aspect 11 or Aspect 12, wherein the reference electrode is comprised of an electrospun nanofiber membrane.

[0054] Aspect 14: Tire electro chemical sensor system of any of Aspects 11 to 13, wherein the electro chemical cell chemical sensor is comprised of at least a working electrode, a reference electrode and a control electrode.

[0055] Aspect 15: The electro chemical sensor system of Aspect 14, wherein the working electrode, reference electrode and control electrode are all comprised of an elctrospun nanofiber membrane.

[0056] Aspect 16: The elcecto chemical sensor system or method of any proceeding Aspect, wherein the nanofiber membrane comprises a conductive polymer in combination with metal nanoparticles, metal oxide nanoparticles or mixtures thereof.

[0057] Aspect 17: The electro chemical sensor system or method of Aspect 16, wherein the conductive polymer is selected from the group consisting of PCL, thermoplastic polyurethane, PEDOT: PSS(G-PEDOT: PSS) and Polyaniline(G-PANT).

[0058] Aspect 18: Tire electro chemical sensor system or method of Aspect 16 or Aspect 17, wherein the conductive metal nanoparticles are selected from the group consisting of nickel, silver, graphite, graphene, copper and gold.

[0059] Aspect 19: The electro chemical sensor system or method of any of Aspects 16 to 18, wherein the metal oxide nanoparticles are selected from the group consisting of MgO, ZnO, TiCK grapheneoxide, zeolites, and combinations thereof.

[0060] Aspect 20: The elector chemical sensor system or method of any proceeding Aspect, wherein one or more nanofiber membrane layers are assembled in a cartridge.

[0061] Aspect 21 : Tire elector chemical sensor system or method of any proceeding Aspect, wherein the one or more nanofiber membranes has a pore size of about 0.2 to about 5 micrometers.

Claims

What is claimed is:

1. An electro chemical sensor system comprising: a potentiostat; and an electrochemical cell connected to the potentiostat, the electrochemical cell comprising at least a working electrode and a reference electrode, wherein at least the working electrode is comprised of a nanofiber membrane.

2. The electro chemical sensor system of claim 1, wherein the nanofiber membrane is electrospun.

3. The electro chemical sensor system of claim 2, wherein the nanofiber membrane comprises a conductive polymer in combination with metal nanoparticles, metal oxide nanoparticles, or mixtures thereof.

4. The electro chemical sensor system of claim 3, wherein the conductive polymer is selected from the group consisting of PCL, thermoplastic polyurethane, PEDOT: PSS(G-PEDOT: PSS) and Polyanilinc(G-PANI) .

5. Tire electro chemical sensor system of claim 3, wherein the conductive metal nanoparticles are selected from the group consisting of nickel, silver, graphite, graphene, copper and gold.

6. Tire electro chemical sensor system of claim 3, wherein the metal oxide nanoparticles are selected from the group consisting of MgO, ZnO, TiCE, graphene oxide, zeolites, and combinations thereof.

7. The electro chemical sensor system of claim 1, wherein the reference electrode is comprised of an electrospun nanofiber membrane.

8. Tire electro chemical sensor system of claim 1, wherein the electro chemical cell chemical sensor is comprised of at least a working electrode, a reference electrode and a control electrode.

9. Tire electro chemical sensor system of claim 8, wherein the working electrode, reference electrode and control electrode are all comprised of an electrospun nanofiber membrane.

10. A method comprising: electrospinning a polymer solution so as to produce a dissolvable nanofiber mesh; exposing the nanofiber mesh to an aerosol containing contaminant particles; and collecting the contaminant particles on the nanofiber mesh.

11. The method of claim 10, further comprising: dissolving the nanofiber mesh with the collected particles in an aqueous solution to create a solution; contacting an electrochemical cell with the solution; and using a potentiostat connected to the electrochemical cell to determine the amount of contaminant in the aerosol.

12. Tire method of claim 11, further comprising using an loT connected to the electrochemical cell to monitor or alter the presence of contaminant in the aerosol.

13. The method of claim 12, further comprising monitoring the contaminant in the aerosol remotely in hazardous conditions.

14. Tire method of claim 11, wherein the electrochemical cell is comprised of at least two electrodes.

15. Tire method of claim 15, wherein the electrochemical cell is comprised of a nanofiber membrane.

16. Tire method of claim 18, wherein the nanofiber mesh comprises an electrostatic polymer in combination with conductive metal nanoparticles, metal oxide nanoparticles, or mixtures thereof.

17. The method of claim 11, wherein the nanofiber mesh contains conductive nanoparticles, the method further comprising: creating an electrochemical cell w ith the conductive particle containing nanofiber mesh; exposing the electrochemical cell to an aerosol containing a target contaminant: and using a potentiostat connected to the electrochemical cell to determine the amount of target contaminant in the aerosol.

18. Tire method of claim 11, wherein the electrochemical cell is a microsensor platfomr selected from the group consisting of a microfluidic optical particle analyzer, a microPCR and a screen printed electrode.

19. Tire method of claim 11, wherein the polymer material is selected from the group consisting of PVA. PVP or composite of PVA-PVP.

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