EP4701669A1

EP4701669A1 - Sensor device

Info

Publication number: EP4701669A1
Application number: EP24717296.8A
Authority: EP
Inventors: Wensheng Xia; Naiyong Jing
Original assignee: Solventum Intellectual Properties Co
Current assignee: Solventum Intellectual Properties Co
Priority date: 2023-04-24
Filing date: 2024-03-26
Publication date: 2026-03-04
Also published as: WO2024224185A1; CN120981255A

Abstract

A conductive polymer composition includes a conductive polymer having a first impedance state and a second impedance state that is different than the first impedance state. The composition further includes a polymeric binder; and surface-modified metal or metal containing particles having a longest average dimension of less than 250 nm. The surface modification of the surface-modified metal or metal containing particles comprises a silane treatment.

Description

SENSOR DEVICE

Background

Sensor devices useful for sterilization monitoring have been described in, for example, U.S. Patents 8,492,162, 8,353,624, and 8,343,437.

Brief Description of the Drawings

The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying figures, in which:

FIG. 1 illustrates a sterilization system that can be used in connection with the sensors of the present disclosure.

FIG. 2 illustrates a sensor device in accordance with some embodiments of the present disclosure.

FIG. 3 illustrates use of a sensor device in a sterilization system in accordance with some embodiments of the present disclosure.

FIG. 4 illustrates use of a sensor device in a sterilization system in accordance with some embodiments of the present disclosure.

While the above-identified drawings, which may not be drawn to scale, set forth various embodiments of the present disclosure, other embodiments are also contemplated, as noted in the Detailed Description. In all cases, this disclosure describes the presently disclosed invention by way of representation of exemplary embodiments and not by express limitations. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of this disclosure.

Detailed Description

Chemical indicators are widely used in sterilization monitoring to ensure the sterilization process has been completed correctly. Failed or insufficient sterilization cycles will put the patients in huge risk due to the potential cross-contaminations from the reprocessed surgical instruments.

Traditional chemical indicators are based on colorimetric changes in the presence of a certain sterilant and its running conditions such as sterilization temperature and sterilization time, etc. For example, a steam indicator may change color from light yellow to black. Another type chemical indicator, known as a Bowie-Dick test pack, is designed to detect air leak or insufficient air removal in a sterilizer.

In the current practice of evaluating a chemical indicator visually, a user needs to visually judge the color development to determine if the chemical indicator was subjected to an adequate sterilization process. However, color development can be subjective. As a result, a more objective system is highly desirable.

Systems having a more objective basis for evaluating chemical indicators have been described. For example, a prior system utilizes a conductive polymer coating solution that, in response to exposure to a sterilant, can shift from a first impedance state to a second impedance state. The conductive polymer coating solution of the prior systems include metal particles dispersed in a solution of a conductive polymer and pre -polymeric binder material. The metal particles are important components for interaction with conductive polymers in that they enable redox chemistries to occur when exposing to a suitable sterilant for consistent sensitive detections. Further regarding such prior coating solutions, it has been discovered that dispersing the metal particles in the coating solutions is challenging for industrial applications, especially when added to the solution in a low-density organic solvent; and that uniform dispersion/concentration of the particles is critical to generate reproducible coatings for chemical indication.

To facilitate uniform dispersion of particles, blending of the particles (e.g., tin nanoparticles) with a high sheering mixer has been attempted. Such a mixing process, however, was discovered to pose many challenges in terms of manufacturability. Since many types of common nanoparticles are in agglomerate form during the manufacturing process and/or during storage due to electric static interaction, it is extremely difficult to break the agglomerates and re -disperse the particles into a solution, even with high energy inputs, such as high sheer mixers or ultrasonic mixers. Moreover, there are several drawbacks to blend the nanoparticles into the coating solution with a high sheer mixer or an ultrasonic mixer. First, the high energy inputs generate heat during the mixing and mechanical sheer stress to the reactive coating solution system, which in turn destabilizes the coating solution and speeds up the gelling of the pre-polymeric binder. Moreover, the heat and the mist generated from the high mixing speed eventually alters the formulation and poses health hazard to operators. Second, direct powder blending is not efficient. Since common inorganic nanoparticles are heavy metals and incompatible with organic conductive polymer solutions, it thus is expected that the powder usually settles down quickly to the bottom even with a high sheer mixer if not added slowly enough and then ends up collecting on the bottom of the container, as opposed to mixing into the solution. Third, due to the inefficiency of powder blending, some agglomerates fail to separate into the desired size and disperse. Consequently, when the coating solution is run through an inline filter on a coating line, as is often the case, these nanoparticle agglomerates tend to block the inline filter and cause coater break down. Finally, due to the inconsistency of direct powder blending such as settling and loss of material via inline filtration, the actual concentration of nanoparticles in the coating solution can vary significantly from lot to lot, thus resulting in inconsistent performance of the resulting coating as a chemical indicating composition.

Lastly, while the addition of dispersants can facilitate dispersion of the particles, use of conventional dispersants is associated with several drawbacks. For example, the dispersion of metallic nanoparticles in organic solvents requires considerable amounts of dispersants. Many conventional dispersants, such as surfactants, are surface active compounds and can impart undesirable properties to the coating formulation. For instance, the dispersion agents can migrate to the surface and affect adhesion of the coating to the substrate or electrical properties of the coated product. In addition, the dispersants also often modify the steam/moisture penetration properties of the solutions, which affect the steam detection capability and product stability during long storage time.

Consequently, compositions and methods to overcome the aforementioned challenges are desirable.

Generally, the present disclosure is directed to compositions and methods that include a family of silane chemistry as a surface modifier to metal or metal containing nanoparticles intended for dispersion in certain pre -polymeric coating solutions. Such surface modification can facilitate gentle (or low energy) dispersion of the nanoparticles in the pre-polymeric coating solutions (even at very low concentrations of modifying reagent) while not negatively impacting the curing chemistry of the solution or the function of the metal or metal containing nanoparticles.

For the following defined terms, these definitions shall be applied for the entire Specification, including the claims, unless a different definition is provided in the claims or elsewhere in the Specification based upon a specific reference to a modification of a term used in the following definitions:

The terms “about” or “approximately” with reference to a numerical value or a shape means +/- five percent of the numerical value or property or characteristic, but also expressly includes any narrow range within the +/- five percent of the numerical value or property or characteristic as well as the exact numerical value. For example, a temperature of “about” 100°C refers to a temperature from 95°C to 105°C, but also expressly includes any narrower range of temperature or even a single temperature within that range, including, for example, a temperature of exactly 100°C. For example, a viscosity of “about” 1 Pa-sec refers to a viscosity from 0.95 to 1.05 Pa-sec, but also expressly includes a viscosity of exactly 1 Pa-sec. Similarly, a perimeter that is “substantially square” is intended to describe a geometric shape having four lateral edges in which each lateral edge has a length which is from 95% to 105% of the length of any other lateral edge, but which also includes a geometric shape in which each lateral edge has exactly the same length.

The term “substantially” with reference to a property or characteristic means that the property or characteristic is exhibited to a greater extent than the opposite of that property or characteristic is exhibited. For example, a substrate that is “substantially” transparent refers to a substrate that transmits more radiation (e.g. visible light) than it fails to transmit (e.g. absorbs and reflects). Thus, a substrate that transmits more than 50% of the visible light incident upon its surface is substantially transparent, but a substrate that transmits 50% or less of the visible light incident upon its surface is not substantially transparent.

The terms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a material containing “a compound” includes a mixture of two or more compounds.

"Adequate sterilization process" refers to a sterilization process that achieves a sterility assurance level of 10 ⁶, or 12 log reduction of Bacillus Subtilis var. Niger. The sterility assurance level is related to a probability that a sterilized unit remains nonsterile after undergoing the sterilization process. "Adequate environmental condition" refers to environmental conditions inside of a sterilization chamber that correspond to the adequate sterilization process.

The phrase "comprises at least one of" followed by a list refers to comprising any one of the items in the list and any combination of two or more items in the list. The phrase "at least one of" followed by a list refers to any one of the items in the list or any combination of two or more items in the list.

Although the term “impedance” is used, the term “impedance” is the reciprocal of the “admittance”. Depending on the context, either impedance or admittance can be used as changes in the impedance of a material also change the admittance of the material.

The term "and/or" means one or all of the listed elements or a combination of any two or more of the listed elements.

All numerical ranges are inclusive of their endpoints and nonintegral values between the endpoints unless otherwise stated (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

Before any embodiments of the present disclosure are explained in detail, it is understood that the present disclosure is not limited in its application to the details of use, construction, and the arrangement of components set forth in the following description. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways that will become apparent to a person of ordinary skill in the art upon reading. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure.

Unless otherwise indicated, all numbers expressing quantities or ingredients, measurement of properties and so forth used in the Specification and embodiments are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached listing of embodiments can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claimed embodiments, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

In some embodiments, the present disclosure relates to a sterilization system and associated sensor device having a sterilant-responsive switch that may be responsive to environmental conditions (including the presence of a sterilant such as steam) in a sterilization process. Generally, the sensor devices of the present disclosure enable electronic reporting of information (e.g., pass/fail information, accept/reject information) regarding each sterilization cycle to avoid subjective judgments that can lead to errors (e.g., perceived change in color by the human eye). Also, the systems and devices of the present disclosure enable digitalization of sterilization results which, in turn, will free technicians from manual document and physical storage. FIG. 1 illustrates a sterilization system 100 in which a sensor device of the present disclosure may be employed. As shown in FIG. 1, the sterilization system 100 may include a chamber 110 into which a sterilant stream 120 may be directed. The sterilization system 100 may be of a type commonly used by hospitals and other medical facilities to sterilize reusable medical devices. Various types of sterilization systems 100 can be employed for purposes of the present disclosure. For example, the sterilization systems 100 can be based on steam or hydrogen peroxide (e.g., vaporized hydrogen peroxide), and each type can have different sterilization process conditions. Examples of sterilizer systems using hydrogen peroxide as a sterilant are commercially available from Steris (Mentor, OH) or Tuttnauer (Israel). Examples of sterilizers using steam as a sterilant are commercially available from Steris (Mentor, OH) or Getinge (Gothenburg, Sweden).

In some embodiments, the chamber 110 can have one or more environmental conditions. The environmental conditions can be related to conditions inside of the chamber 110 and can include, for example, exposure time, sterilant (presence, concentration, etc.), temperature, pressure, or combinations thereof. In some embodiments, a first environmental condition can exist pre- sterilization process and a second environmental condition can exist during the sterilization process.

In some embodiments, the present disclosure is directed to a sensor device that is configured to determine whether a sterilization process within a sterilization system is carried out in accordance with a predetermined guideline or whether an adequate sterilization process was achieved. An adequate sterilization process can vary based on the sterilant used, the manufacturer of the sterilizer, or the articles to be sterilized. For example, Guideline for Disinfection and Sterilization in Healthcare Facilities, Center for Disease Control (2008), which is herein incorporated by reference in its entirety, provides minimum cycle times for sterilization of various article types and sterilant s.

Referring to FIG. 2, a sensor device 130 in accordance with some embodiments of the present disclosure is depicted. The sensor device 130 may include a first electrode 135, a second electrode 140 (sometimes, collectively, referred to as an electrode pair), and a sterilant -responsive electrical bridge 145 which may facilitate electrical communication between the first electrode 135 and the second electrode 140. In some embodiments, each of the first electrode 135 and the second electrode 140 may be in electrical communication, or electrically coupled, (either via physical contact or via an intermediate such as a conductive member (e.g., an electrically conductive wire)) via the sterilant - responsive electrical bridge 145.

As shown in FIG. 2, in some embodiments, at least one end of each of the first electrode 135 and the second electrode 140 may be in physical contact with the sterilant -responsive electrical bridge 145. For example, the electrical bridge 145 may be formed as a layer of material that is deposited onto and spans across the first electrode 135 and the second electrode 140. In such embodiments, the electrical bridge may be deposited or coated on the first and second electrodes 135, 140 at a thickness of between 0.1 and 100 microns, between 1 and 50 microns, or between 5 and 25 microns.

In some embodiments, absent the sterilant -responsive electrical bridge 145, the electrode pair

135, 140 may not be capable of electrical communication (i.e., the electrodes are not physically touching or are spaced apart at least a distance such that there is no electrical communication without an intervening conductive member such as the electrical bridge 145).

In some embodiments, the first and second electrodes 135, 140 may include a metal such as aluminum, iron, zinc, tungsten, molybdenum, tin, nickel, copper, or alloys thereof, or carbon black, graphene, carbon nanotubes, or a conducting polymer.

In some embodiments, the electrical bridge 145 may be configured to have a first impedance state (e.g., high impedance/no or low conductivity) and a second impedance state that is markedly different than the first impedance state (e.g., low impedance/high conductivity (or vice versa). For example, in some embodiments, in a first state, the electrical bridge exhibits a low impedance and in a second state exhibits a high impedance (relative to the low impedance state). In some alternative embodiments, in a first state, the electrical bridge exhibits a low electric capacitance and in a second state exhibits a high electric capacitance (relative to the low electric capacitance state) or vice versa.

In some embodiments, referring still to FIG. 2, the electrical bridge 145 may include a conductive polymer composition configured to exhibit the above described first and second impedance states. In some embodiments, the conductive polymer compositions of the present disclosure may be composite materials that include a conductive polymer, a plurality of one or more types of surface-modified metal or metal containing particles, and a polymeric binder.

Generally, the conductive polymer of the conductive polymer composition can be any polymeric material that is shiftable between a first impedance state and a second impedance state. In some embodiments, suitable conductive polymers may be those capable of being converted from a first impedance state to a second impedance state in response to a change of environmental conditions (e.g., transitioning from the first state to the second state upon contact with a sterilant, or transitioning from the first state to the second state upon achievement of an adequate sterilization process within a sterilizer system). In some embodiments, the first state can be a low impedance state and the second state can be a high impedance state (or vice versa). In some embodiments, the low impedance state can be a doped (e.g., acid doped) electrically conductive state and the high impedance state can be a de-doped (e.g., by inclusion and activation of a basic material) electrically non -conductive (or at least a conductivity lower than that of the electrically conductive state). In some embodiments, a low impedance state refers to a state having an admittance sufficient to electrically bridge an open circuit, e.g., having an admittance of at least 2 siemens.

In some embodiments, the conductive polymer of the conductive polymer composition can have a repeat unit of: aniline, acetylene, pyrrole, phenylene, phenylene vinylene, phenylene ethynylene, phenylene sulfide, fluorene, pyrene, azulene, naphthalene, carbazole, indole, thiophene, ethylene dioxy thiophene, or combinations thereof. The conductive polymer material can be doped or undoped with various dopants such as dinonylnaphthalene sulfonic acid (DNNSA), dodecylbenzenesulfonic acid (DBSA), arsenic pentafluoride, triiodide, camphorsulfonate, methanesulfonic acid, halogens or polyhalogen ions, methanol, hydrogen sulfate, hydrochloric acid, tetrafluoroborate, sodium sulfite, or combinations thereof. In some embodiments, the conductive polymer of the conductive polymer composition may include (or consist essentially of) poly aniline (PANI). In some embodiments, the conductive PANI is in a form of electrolytes, polyelectrolytes, or PANI salts which can be readily achieved by acid-doping of PANI. PANI can be in one of three oxidation states (leucoemeraldine, emeraldine (in the salt or base forms), and per(nigraniline)). The emeraldine can be non-conductive in the base form and conductive in the polyelectrolyte form or the salt form. The emeraldine salt can be converted into the leucoemeraldine salt or per(nigraniline) which are non-conductive, via a redox reaction. The conductive polymer can be converted to non-conductive polymer via a de-doping reaction. In some embodiments, the conductive polymer material of the present disclosure may be present, initially, in the emeraldine salt form and be convertible to the leucoemeraldine salt form upon exposure to a sterilant.

In some embodiments, conductive polymer may be present in the conductive polymer composition in an amount of at least 5 wt. %, at least 10 wt. %, at least 30 wt. %, at least 50 wt. %, or at least 90 wt. %, based on the total weight of the conductive polymer composition (or composite material that forms the electrical bridge 145).

In some embodiments, suitable metal or metal containing particles may include electrically conductive metal particles. Additionally, or alternatively, in some embodiments, the metal particles may be characterized as redox particles (i.e., particles that facilitate a chemical reaction in the electrical bridge 145 in the presence of a sterilant (e.g., steam) that involves loss of one or more electrons by one molecule (oxidation - metal redox particle) and simultaneous gain by another (reduction - conductive polymer)). In some embodiments, suitable metal redox particles may include aluminum, tin, bismuth, nickel, lead, Indium, chromium, gallium, iron, vanadium, cadmium, titanium, zirconium, nobelium, tungsten, thallium, germanium, or lanthanides. In some embodiments, the metal particles may include tin. In some embodiments, suitable metal particles may include metal alloy, such as silver-tin alloy, gold-tin alloy, or indium-tin alloy.

In some embodiments, useful metal redox particles may be those that can release electrons upon exposure to a sterilant (e.g., steam). For example, suitable metal redox particles may include those that can be activated to release electrons to reduce PANI electrolytes or polyelectrolytes (protonated forms) to its leucoemeraldine salt form. An examples of such a mechanism is below:

Emeraldine Salt (conductive) Leucoemeraldine Salt (Less/non-conductive)

In some embodiments, suitable metal or metal containing particles may include electrically conductive metal particles, non-conductive metal oxides, metal complexes or a combination thereof, which may be characterized as catalyst particles (i.e., particles that catalyze a chemical reaction in the electrical bridge 145 in the presence of a sterilant (e.g., hydrogen peroxide) that involves the formation of byproducts that result in a local pH increase near the conductive polymer). In some embodiments, suitable metal catalyst particles may include magnesium, copper, cobalt, manganese, zinc, iron, silver, platinum, osmium, iridium, lead palladium, ruthenium, rhodium, gold, chromium, iron, vanadium, cadmium, titanium, zirconium, nobelium, tungsten, thallium or their oxidates and complexes. In some embodiments, suitable metal containing catalyst particles may include magnesium oxide, iron oxide, manganese oxide, zinc oxide, iron oxide, potassium dichromate, vanadyl acetylacetonate, 1 :1 copper(II)-, manganese (II)-, cobalt(TT)- or nickel(II)-hexamine complexes. In some embodiments, suitable metal catalyst particles may include copper.

In some embodiments, useful metal catalyst particles may include those that can catalyze a reaction with the sterilant (e.g., hydrogen peroxide) to generate hydroxide anions and water as byproducts. The presence of hydroxide anions may, in turn, increase the local pH near the conductive polymer, which may result in the capture of protons to neutralize PANI electrolytes or polyelectrolytes (protonated forms) to its neutral or less protonated emeraldine form. An example of such a set of reactions (using hydrogen peroxide as the sterilant) is below:

OH_(5ds) + f ■■ OH - (2)

2OH" -r 2H'^;' 2H₂O. (3)

In some embodiments, useful metal or metal containing particles may include those that can be activated by a sterilant (e.g., steam or hydrogen peroxide) to generate free electrons, hydrides, or hydrogen which are capable of reducing a conductive polymer from a first conductive state to a second conductive state (e.g., converting PANI from the emeraldine salt (ES) state to the leucoemeraldine salt (LS) state). Examples of such a set of reactions are shown below (unbalanced equations): M + H20 (steam) MO + H⁺ + e

M + H2O (steam) MO + H"

M H₂

M can be monovalent or multivalent metals

As discussed above, in some embodiments, the metal or metal containing nanoparticles may be treated with a surface treatment agent to facilitate dispersion of the particles in a coating solution. In general, such surface treatment agents may have a first end that will attach to the particle surface (covalently, ionically or through strong physiosorption) and a second end that imparts compatibility of the particle with the coating solution. In some embodiments, the surface treatment agents may include silanes. Surface modification can be accomplished either subsequent to mixing in the coating solution or after mixing. In some embodiments, silane surface treatment agents may be reacted with the particle or nanoparticle surface before incorporation into the coating solution. The amount of surface modifier can depend on factors such as particle size, particle type, modifier molecular weight, and modifier type. In general, a monolayer of modifier is attached to the surface of the particle. The attachment procedure or reaction conditions required also depend on the surface modifier used. For silanes, surface treatment may take place at elevated temperatures under acidic or basic conditions during a period of about 1 hour up to about 24 hours.

In some embodiments, suitable silane surface treatment agents may include one of or any combination of two or more of isooctyl trimethoxy-silane, N-(3-triethoxysilylpropyl) methoxyethoxyethoxyethyl carbamate (PEG3TES), SILQUEST™ A1230, N- (3 -triethoxy silylpropyl) methoxyethoxyethoxyethyl carbamate (PEG2TES), 3-(methacryloyloxy)propyltrimethoxysilane, 3- acryloxypropyltrimethoxysilane, 3 -(methacryloyloxy)propyltriethoxysilane, 3 -(methacryloyloxy) propylmethyldimethoxy silane, 3 -(acryloyloxypropyl)methyldimethoxysilane, 3 -

(methacryloyloxy)propyldimethylethoxysilane, 3 -(methacryloyloxy) propyldimethylethoxysilane, vinyldimethylethoxysilane, isobutyltrimethoxysilane, (3,3,3-Trifluoropropyl)trimethoxysilane, n- octyltrimethoxysilane, dodecyl trimethoxy silane, octadecyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, vinylmethyldiacetoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrimethoxy silane, vinyltriphenoxy silane , vinyltri -t-butoxy silane , vinyl tris -isobutoxy silane , vinyl triisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, styrylethyltrimethoxysilane, mercaptopropyltrimethoxysilane, and 3 -glycidoxypropyltrimethoxy silane. In some embodiments, suitable silane surface treatment agents may include one of or any combination of two or more of vinyldimethylethoxysilane, isobutyl trimethoxy silane, (3,3,3- Trifluoropropyl)trimethoxysilane, n-octyltrimethoxy silane, and propyltrimethoxy silane .

In some embodiments, suitable silane surface treatment agents may include one of or any combination of two or more of any fluorinated or non-fluorinated short alkyl chain trimethoxysilane or dimethoxy silane compound having from 1 to 8 carbon atoms.

In some embodiments, the surface modifying agent may be added to the particles at an extremely low concentration. For example, the surface modifying agent may be added to the particles in an amount of between 0.005 wt.% and 5 wt.% or between 0.02 wt.% and 0.5 wt. %, based on the total weight of the nanoparticles. It was discovered that even at such low concentrations of surface modifying agent, the function of the particles (e.g., redox properties) was maintained while not impacting the curing of the prepolymeric binder components of the coating solution.

In some embodiments, the surface modifying agent may cover the surface area of the particles in an average amount of between 5% and 100%, between 10% and 90 %, or between 40% and 80%, based on the total surface area of the particles.

In some, the surface modified metal or metal containing particles may be nanoparticles. In this regard, the particles may have an average size (in terms of average longest dimension) of between 0.01 microns and 0.1 micron or between 0.001 micron and 1 micron; or no greater than 5 microns; or no greater than 250 nanometers (nm); or no greater than 200 nm. In some embodiments, the surface modified metal or metal containing particles may be spherical, non -spheric al, or a combination thereof.

In some embodiments, the surface modified metal or metal containing particles may be present in the conductive polymer composition in an amount of at least 0.01 wt. %, at least 0.1 wt. %, at least 1.0 wt. %, at least 5 wt. %, or at least 20 wt. %, based on the total weight of the conductive polymer composition (or the composite material that forms the electrical bridge 145); or between 0.1 wt. % and 30 wt. %, between 0.5 wt. % and 20 wt. %, between 0.5 wt. % and 10 wt. %, or between 1 wt. % and 15 wt.%, based on the total weight of the conductive polymer composition (or the composite material that forms the electrical bridge 145). Generally, the amount of metal or metal containing particles present in the electrical bridge may be that which is necessary to convert the conductive polymer from the first impedance state to the second impedance state acid state upon exposure to a sterilant.

In some embodiments, the conductive polymer compositions of the present disclosure may include a polymeric binder. Suitable polymeric binders may include a polyurethane, a polyvinyl butyral, a polyacrylate, polyvinyl acetate, polystyrene, polystyrene acrylate, a polyurea, a polyimide, an amide, an epoxy, a glycidyl-Si-Zr-containing solgel, a polyester, a phenoxy resin, a polysulfide, or mixtures thereof.

In some embodiments, polymeric binder may be present in the electrical bridge 145 in an amount of at least 5 wt. %, at least 10 wt. %, at least 40 wt. %, at least 50 wt. %, or at least 90 wt. %, based on the total weight of the conductive polymer composition (or the composite material that forms the electrical bridge 145); or between 5 wt. % and 99 wt. %, between 10 wt. % and 95 wt. %, between 20 wt. % and 95 wt.%, or between 40 wt. % and 95 wt.%, based on the total weight of the conductive polymer composition (or the composite material that forms the electrical bridge 145).

In some embodiments, the conductive polymer compositions of the present disclosure may be formed by dry down of a pre-polymer solution that is the combination of the above-described conductive polymer, a pre -polymeric (curable) form of the polymeric binder, and a solvent-based dispersion of the surface modified nanoparticles.

In some embodiments, the conductive polymer may be present in the pre-polymer solution in an amount of between 5 wt. % and 60 wt. %, between 10 wt. % and 50 wt. %, or between 20 wt. % and 40 wt. %, based on the total weight of the pre-polymer solution.

In some embodiments, the pre-polymeric (curable) form of the polymeric binder may be present in the pre-polymer solution in an amount of between 1 wt. % and 100 wt. %, between 20 wt. % and 80 wt. %, or between 30 wt.% and 70 wt. %, based on the total weight of the pre-polymer solution. In some embodiments, the pre-polymeric (curable) form of the polymeric binder may be curable via thermal cure or electromagnetic radiation cure (e.g., UV light).

In some embodiments, the solvent-based dispersion may include a solvent and the surface modified nanoparticles. Suitable solvents may include xylene, heptane, hexane, MIBK, ethyl acetate, butyl acetate, toluene, or combinations thereof. Solvent may be present in the solvent-based dispersion in an amount of between 50 wt. % and 99 wt. %, between 40 wt.% and 80 wt. %, or between 50 wt.% and 70 wt. %, based on the total weight of the solvent-based dispersion. Surface modified nanoparticles may be present in the solvent-based dispersion in an amount of between 10 wt.% and 99 wt. %, between 40 wt.% and 80 wt. %, or between 50 wt.% and 70 wt. %, based on the total weight of the solvent-based dispersion.

In some embodiments, the solvent-based dispersion may be present in the pre-polymer solution in an amount of between 0.1 wt.% and 20 wt. %, between 0.5 wt.% and 10 wt. %, or between 1 wt.% and 5 wt. %, based on the total weight of the pre-polymer solution.

In some embodiments, the present disclosure is further directed to methods of making the above-described pre-polymer solution. The methods may include preparing a first composition that includes the conductive polymer and the pre-polymeric (curable) form of the polymeric binder. The method may then include preparing a second composition (the pre -dispersed particle solution) that includes the surface-modified particles and solvent. The method may then include mixing (e.g., gentle mixing via a magnetic mixer or a mechanic blender) of the first and second compositions to form the above-described pre-polymer solution.

In an effort to overcome some the manufacturing and consistency issues discussed above, it was discovered that by employing the above-described silane chemistry to modify the particles in solvent(s), the particles could be successfully dispersed a highly concentrated solution. The subsequent gentle mixing of the pre-dispersed solvent-based solution into a composition that includes the conductive polymer and pre-polymeric binder without aggressive blending force rendered very consistent performance for coatings produced from deposition of the pre-polymer coating solutions of the present disclosure. The employment of pre-dispersed particles also improved the pot life of the coating solution that effectively avoided the unexpected and sudden gelling of the coating solution during coating process, which contributed to coating line breakdown due to blockages in process equipment (e.g. coating head, pump, pipes, etc.)

In some embodiments, as a function of change in impedance state, the electrical bridge 145 may exhibit a change in color. For example, in embodiments in which the electrical bridge 145 includes PANI, the electrical bridge 145 may begin in a first impedance state having a first color (e.g., green) and a second impedance state having a second color (e.g., blue or yellow). In this manner, visual determination of the adequacy of a sterilization cycle may be carried out.

In some embodiments, upon deposition and/or curing of the pre-polymer solution, the surface modified particles of the present disclosure may be uniformly distributed within the resulting conductive polymer composition, or composite material. In this context, “uniformly distributed” means that the density of particles in any first portion of the composite material does not vary by more than 40%, more than 25%, more than 10%, or more than 5% when compared with any second, different portion of the composite material.

In some embodiments, upon deposition and/or curing of the pre-polymer solution, the conductive polymer, polymeric binder, and surface modified particles may be uniformly distributed within the resulting conductive polymer composition, or composite material. In this context, “uniformly distributed” means that the density of any one component in any first portion of the composite material does not vary by more than 20%, more than 15%, more than 10%, or more than 5% when compared with any second, different portion of the composite material.

Referring now to FIG. 3, use of the sensor device 130 in sterilization system 100 in accordance with some embodiments of the present disclosure is illustrated. As shown, the sensor device 130 may be disposed within the chamber 110 of sterilization system 100. In some embodiments, the sensor device 130 may be disposed within the chamber 110 such that it may interact with the component(s) of the sterilant stream 120 upon entry into the chamber 110.

In some embodiments, the sensor device 130 may be a stand-alone device that can be placed into a sterilization system 100. In further embodiments, the sensor device 130 may be incorporated into another device (e.g., sterilization process challenge device with a torturous path such as porous matrix or a lumen channel, Bowie -Dick test pack, or the like) which may include a housing and one or more internal components or materials that are configured to facilitate assurance that adequate sterilization conditions are present during a sterilization cycle.

In some embodiments, a reader device 160 may also be provided. The reader device 160 may be configured to receive signals from the sensor device 130 and translate the received signal into a determination that relates to the adequacy of a sterilization cycle (e.g., a pass/fail determination). For example, the reader device 160 may be configured to interrogate the sensor device 130 such that the reader device 160 measures the impedance across the electrode pair (e.g., induvial readings or continuous or semi-continuous readings over time) which can correspond to whether various environmental conditions were or were not achieved in the sterilization process, or whether an adequate sterilization process was achieved. In some embodiments, when exposed to a first environmental condition (e.g., ambient conditions), the reader device 160 (if interrogating the sensor device) would measure a first impedance value that is indicative of whether the conductive polymer of the electrical bridge 145 is in a first impedance state or a second impedance state. As described above, an environmental condition change (or second environmental condition) within the chamber 110 can change the impedance state of the conductive polymer and, in turn, the impedance across the electrode pair measured by the reader device 160. In some embodiments, when the conductive polymer is in the first impedance state a first resistance is measurable across the first and second electrode, and when the conductive polymer is in the second impedance state a second resistance is measurable across the first and second electrode, and the first resistance is different than the second resistance.

In some embodiments, the reader device 160 may be in electronic communication (or capable of electronic communication) (continuously or at any desired interval) with the sensor device 130 (e.g., wireless communication such as Bluetooth, RF, or Near-Field communication, or wired communication via a suitable electronic connection (e.g., a pair of electrical leads that may be coupled to an electrode pair of the sensor device 130)). In some embodiments, the reader device 160 may be a device for measuring electrical resistance (e.g., an electrical multimeter).

Referring now to FIG. 4, use of the sensor device 130 in a sterilization system 100 in accordance with some embodiments of the present disclosure is illustrated. As shown, the sensor device 130 may again be disposed within the chamber 110 of sterilization system 100 such that it may interact with the component(s) of the sterilant stream 120 upon entry into the chamber 110. Additionally, one or more medical devices 165 to be sterilized may be disposed with the chamber 110. For example, as shown, the sensor device 130 and the one or more medical devices 165 may be housed to together in a package 170 (often referred to in industry as a tray). It is to be appreciated that each package 170 may house any number of medical devices 165 or number of sensor devices 130. Alternatively, the sensor device 130 and the one or more medical devices 165 may be housed separately within the chamber 110. As shown, embodiments, a reader device 140 may also be provided.

In some embodiments, the present disclosure further relates to methods of using the sensor device 130 in a sterilization system 100. The method may begin with a user placing the sensor device 130 in the chamber 110. As previously discussed, the sensor device 130 may be placed alone in the chamber 110 or may be placed with one or more medical devices to be sterilized (and may be packaged in a tray with medical devices or disposed in the chamber 110 separate from the medical device or medical device tray). After the sensor device is placed in the chamber, the chamber 110 can be sealed from the environment. In some embodiments, a user can then activate a sterilization process of the sterilizer and the sensor device can be exposed to a sterilant and/or one or more environmental conditions in a sterilization process. For example, if the sterilant is steam, then the sterilant may be at least 95% saturated steam/water vapor and the sterilization process may include achieving a temperature within the chamber 110 of at least 132 or at least 134 degrees Celsius for at least 2 minutes or at least 121 degrees Celsius for at least 8 minutes or at least 10 minutes. As an additional example, if the sterilant is hydrogen peroxide, then the sterilant may be in an atmosphere containing at least 30% hydrogen peroxide vapor and the sterilization process may be carried out at least 50 degrees Celsius for at least 60 minutes. Various standards for each sterilant can exist and may vary based on the manufacturer, article to be sterilized, or combinations thereof.

In some embodiments, as discussed above, exposing the sensor 130 to the sterilant and/or the conditions within the chamber 110, may result in a change of the impedance state of the conductive polymer of the electrical bridge 145.

In some embodiments, the method may further include continuously, intermittently, or at any desired time, the reader device 160 receiving signals from the sensor device 130 and translating such received signal into a determination that relates to the adequacy of a sterilization cycle (e.g., a pass/fail determination). As discussed above, the received signals may relate to a measured impedance across the electrode pair, which corresponds to various environmental conditions that were or were not achieved in the sterilization process. For example, a measured impedance above or below a predetermined value may be used to determine whether adequate sterilization process conditions were achieved within the chamber 110.

Examples

These examples are merely for illustrative purposes only and are not meant to be limiting on the scope of the appended claims. All parts, percentages, ratios, etc. in the examples and the rest of the specification are by weight, unless noted otherwise. Solvents and other reagents used were obtained from FUJIFILM Wako Pure Chemical Corp, or Sigma-Aldrich Chemical Company; Milwaukee, Wisconsin unless otherwise noted. The following abbreviations are used: mm = millimeters; mL = milliliters; in = inches; g = grams; mg = milligrams; kg = kilograms; hrs = hours; nm = nanometers.

Table 1. Materials.

Example 1

Preparation of C8-silane samples: Four portions of octyltrimethoxysilane (C8) weighing 12.6, 26, 50 and 111 mg were weighed into 20 mL glass vials. Then 13.6 g of 1:1 (w/w) xylene and MIBK were added to each vial and mixed well. To each resulting solution, 2.4 g of tin nanoparticles were added and then sonicated in a sonication bath for two hours.

Preparation of PEG-Silane samples: The same procedure was followed as for C8-silane. Two samples were prepared using 20 mg and 48 mg PEG-silane to make 15% tin concentration.

Preparation of Cl -silane and vinyl-Silane samples: The same procedure was followed as C8-silane using 50 mg Cl to make 15% tin concentration.

A control sample was prepared without addition of any dispersants by adding 2.4 grams of tin nanoparticles to 13.6 of 1:1 (w/w) xylene/MIBK and sonication for 2 hours.

All samples were allowed to sit still on a bench top for 48 hours and the particle settling behavior was observed. Results are shown in Table 2. Table 2. Particle suspension results from sonication treatment with selected silane modifiers. Vinyl (50 mg) tin partially suspended

Example 2

Sixty grams tin nanoparticles were pre-dispersed in 340 g of 1 : 1 (w/w) xylene/MIBK by sonication for 2 hours, then 0.15 g TMFS was added and sonication continued at 40°C for two hours. A control sample was prepared using the same procedure without a modifying compound. The samples were allowed sit still on a bench top and observed for particle settling for two weeks. Table 3 shows the particle dispersion properties.

Table 3. Particle suspension results from sonication treatment with selected silane modifiers.

Example 3

Sixty grams of tin nanoparticles were mixed with 170 g xylene and 170 g MIBK. The mixture was shaken a few times by hand and then 0.3 g of TFMS was added and the mixture was shaken again. The resulting suspension was transferred to a jacketed beaker with a circulation temperature of 40°C. The suspension was stirred with a magnetic stirring bar to create a swirling suspension. A sonicator head was placed into the solution and the suspension was sonicated. About 2 mF of sample solution was drawn at 0.5 and 1 hr. Each sample was diluted by 1 : 1 xylene/MIBK to 1 % for particle analysis with a Horiba Particle Analyzer. Table 4 shows the particle analysis data for 0.5 hr sonication and Table 5 for 1 hr sonication.

Table 4. Particle size distribution of modified tin nanoparticles with sonication for 0.5 hr.

Size (d.nmj: % Intensity: St Dev (d.n...

Peak l : 1245 55.7 657.4

Peak 2: 185.6 39.7 60.36

Peak 3: 4634 4.6 741 .3

Table 5. Particle size distribution of modified tin nanoparticles with sonication for 1 hr.

Size (d.nm): % Intensity: St Dev (d.n

Peak ! : 152.2 97.7 38.15

Peak 2: 5224 2.3 459.2

Peak 3: 0.000 0.0 0.000

From Tables 4 and 5, one can see that a majority of particles were 1 micron size (-56%). However, after 1 hr of sonication time, almost 98% particles were converted to around 150 nm with only 2% of particles near 5 microns. Example 4

60 grams of tin nanoparticles were mixed with 170 g of xylene and 170 g of MIBK. The mixture was shaken a few times by hand and then 0.3 g of TFMS was added and then mixture shaken again. The resulted suspension was transferred to a jacketed metal beaker with a circulation temperature at 40°C. An Omni Ultra Shear homogenizer (Lab M Model) was used to mix the suspension for 4 hours at 10,000 rpm. Samples were taken from the concentrated suspension and diluted in 1 :1 xylene/MIBK to determine the particle size distribution with a Horiba particle analyzer. Table 6 shows the particle distribution after 4 hours of homogenizer mixing. 100% of the tin nanoparticles were converted to less than 80 nm size. The suspended solution at 15% was diluted to 3% with 1 :1 xylene/MIBK solvent mix and passed through a 10 microliter polypropylene filter (VWR). The solids content of the resulting filtered solution was determined by evaporating the solvent at 150°C for 2 hours. A sample without TFMS was sonicated for 20 minutes in 1/1 xylene/MIBK solvent mix at 3 wt% tin nanoparticles and was used as a control. Table 7 shows the final filtration effect and final solid content.

Table 6. Particle size distribution of modified tin nanoparticles with high shearing mixing

Size (d.nm): % Number: St Dev (d.n...

Peak 1 1000 67.17

Peak 2: 0.000 0.0 0.000

Peak 3: 0.000 0.0 0 000

Table 7. Percent solid for 3% modified tin in solvent.

Example 5

A coating solution comprising poly aniline and polyurethane was prepared as shown in Table 8. The solution was stirred with a small magnetic stirring bar for one hour before coating. To the solution, 15% TFMS -modified tin solution was added to the PANI/PU mix at 1:10 ratio and gently mixed with a magnetic stirring bar made through Example 1 and Example 3. A control sample was used to add tin nanoparticle directly at 1.5% of the total solution and sonicated for 20 min. A silver/carbon printed open circuit (Molex LLC, Naperville, IL) was coated with the solution using a #16 Mayer bar and then cured at 140°C for 4 minutes with tin concentration around 6.93% in final coated film. This coated silver/carbon printed open circuit was attached to a blotter paper card from a 3M Comply Bowie Dick test pack, providing a silver circuit card. The initial electric resistance of the coated silver printed open circuit was measured with a multimeter. Table 8. PANI/PU coating solution.

A commercial COMPLY Bowie-Dick test pack (3M Company, St. Paul, MN) was carefully opened by cutting a slit along the tip of the wrapping paper located underneath the label stock. This test pack comprises a pack or deck of blank blotter paper cards with a Bowie-Dick chemical indicator card in the middle of the blank blotter paper cards, all of which are wrapped with paper. The silver circuit cards were used to replace two of the original blotter paper cards in the opened Bowie -Dick test pack. One silver circuit card (card 1) replaced the fifth card ahead of the chemical indicator card and another silver circuit card (card 2) replaced the card immediately after the chemical indicator card. The chemical indicator card was maintained in its original position. This modified card stack was re-wrapped with the original wrapping paper and sealed with a small piece of SCOTCH tape (3M Company, St. Paul, MN) to close the opening on the label stock.

This modified Bowie-Dick test pack was then subjected to a Bowie-Dick test cycle with a sterilization time of 3.5 minutes at 132°C in an AMSCO Eagle 3013 steam sterilizer (Steris pic, Mentor, OH). After completion of the Bowie -Dick test cycle, the test pack was opened, the silver circuit cards were removed, and the conductivity of the attached circuits measured with a multimeter. Table 9 shows the electric resistance measurement results. The results showed that a silver circuit coated with lithium carbonate doped PANI can serve as an electric chemical indicator in an air removal test.

Table 9. Bowie-Dick test pack testing results. Example 6

Five samples of 17.5 wt% tin nanopowder dispersed in 1:1 xylenes/MIBK were made. To these dispersions were added silanes in the noted amounts. The dispersions were then sonicated at room temperature overnight. The dispersion stability was monitored over time and the results are provided in Table 10. Stability refers to the time before significant sedimentation occurred.

Table 10. Stability of tin nanoparticle suspensions of Example 6.

Example 7

Five samples of 17.5 wt% tin nanopowder dispersed in 1:1 Xylenes/MIBK were made. To these dispersions were added silanes in the noted amounts. The dispersions were then sonicated at 40 °C for 1.5 hours. The dispersion stability was monitored over time. Water in methanol (1:9 PECf McOH) was added to the samples in the noted amounts and the samples were vortexed to mix and then sonicated again at 40 °C for 1.5 hours. The dispersion stability was again monitored over time and the results are provided in Table 11. Stability refers to the time before significant sedimentation occurred.

Table 11. Stability of tin nanoparticle suspensions of Example 7 Example 8

Five samples of 17.5 wt% tin nanopowder dispersed in 1:1 Xylenes/MIBK were made. To these dispersions were added silanes and water in methanol (1:9 EhCkMeOH) in the noted amounts. The dispersions were vortexed to mix and then sonicated at 40°C for 1.5 hours. The dispersion stability was monitored over time and the results are provided in Table 12. Stability refers to the time before significant sedimentation occurred.

Table 12. Stability of tin nanoparticle suspensions of Example 8.

Example 9

Sample A, B and D described in Run 3 were separately mixed with PAN/PU solution as described in Experiment 5 in weight ratios described in the following Table. The resulting mixed solutions were vortexed for 30 seconds and subsequently a sonicated for 2-3 hours. The Tin particles were well dispersed in solutions. The solutions were placed on a bench and the particles remained dispersed in the solutions for at least 2 hours and the results are provided in Table 13. Stability refers to the time before significant sedimentation occurred.

Table 13. Stability of tin nanoparticle suspensions of Example 9.

Example 10

Four lots of 3 kg each of the coating solutions provided in Table 10 were made without tin. After solutions were made, 45 g of tin (total mass based) was added slowly into the PANI/PU solution with a high shear mixer and then mixing continued for 20 minutes. The solution was again mixed for an additional 20 minutes with a high shear mixer immediately prior to coating and then transferred to a coating sump with an air mixer to keep the solution agitated. The solution was coated through a coating die after passing a 50 micrometer inline filter to coat onto a PET surface. Tin concentrations in some of the lots recovered from coating sump after coating was completed were determined by inductively coupled plasma method. Table 14 contains the observation results from each run. Table 14. Results for coatings of Example 10.

Example 11

Six grams of copper nanoparticles were mixed with 17 g of xylene and 17 g of MIBK. The mix was shaken a few times by hand and then 0.03 g of TFMS was added and shake again. The resulted suspension was sonicated at 40°C for overnight. The suspension was then diluted to 1% with 1/1 xylene and MIBK solvent mix and passed through a 10 micrometer filter. The solution was then subjected to particle size distribution analysis using a Horiba particle analyzer. As a control, the same copper suspension was prepared without TFMS, and the resulting solution was unable to pass through the 10 micron filter. Table 15 shows the particle distribution of the 1% copper nanoparticle suspension, and it can be seen that 82% of the particles were reduced to around 52 nm and 18% around 335 nm.

Table 15. Particle size distribution of modified copper nanoparticles.

Size (d.nm): % Number: St Dev (d.n

Peak 1: 335.5 18.0 198.2

Peak 2: 4252 □.0 1012

Peak 3: 52.32 81.9 10.37

Example 12

A poly aniline and polyurethane coating solution was prepared as provided in Table 16. The solution was stirred using a small magnetic stirring bar for one hour before coating. To separate portions of the solution, TFMS-modified 10% and 5% copper solutions were added to the PANI/PU mixture at 1:10 ratio and gently mixed using a magnetic stirring bar. The concentrations of tin in dried film coated from 10% and 5% copper stock suspension are 4.73% and 2.42% respectively. A control sample coating containing no copper was also prepared with the same amount of 1 :1 xylene/MIBK solution. A silver/carbon printed open circuit (Molex LLC, Naperville, IL) was coated with each solution using a #16 Mayer bar and the coating was cured at 140°C for 6 minutes. Each coated silver/carbon electrode pair was exposed to vaporized hydrogen peroxide using an ASP 100S sterilizer. The initial electric resistance and the final resistance of each coated silver printed open circuit was measured with a multimeter. Table 17 provides the resistance change of the copper nanoparticle-doped polyaniline conductive layers and the control coating before and after exposure to hydrogen peroxide. Table 16. PANI/PU coating solution.

Table 17. Resistance of circuits comprising modified copper nanoparticles before and after exposure to vaporized hydrogen peroxide.

Claims

What is claimed is:

1. A conductive polymer composition comprising: a conductive polymer having a first impedance state and a second impedance state that is different than the first impedance state; a polymeric binder; and surface -modified metal or metal containing particles having a longest average dimension of less than 250 nm, wherein the surface modification of the surface-modified metal or metal containing particles comprises a silane treatment.

2. The conductive polymer composition of claim 1, wherein the conductive polymer is present in the conductive polymer composition in an amount of at least 5 wt. %, based on the total weight of the conductive polymer composition

3. The conductive polymer composition of any one of the previous claims, wherein the surface modified metal or metal containing particles are present in the conductive polymer composition in an amount of between 0.5 wt. % and 10 wt.%, based on the total weight of the conductive polymer composition.

4. The conductive polymer composition of any one of the previous claims, wherein the polymeric binder is present in the conductive polymer composition in an amount of between 40 wt. % and 95 wt. %, based on the total weight of the conductive polymer composition.

5 The conductive polymer composition of any one of the previous claims, wherein the conductive polymer, polymeric binder, and surface modified particles are uniformly dispersed in the conductive polymer composition.

6 The conductive polymer composition of any one of the previous claims, wherein the surface modified particles are uniformly dispersed in the conductive polymer composition.

7 The conductive polymer composition of any one of the previous claims, wherein the metal or metal containing particles comprise aluminum, tin, bismuth, nickel, lead, indium, chromium, gallium, iron, vanadium, cadmium, titanium, zirconium, nobelium, tungsten, thallium, germanium, lanthanides, or alloys thereof.

8 The conductive polymer composition of any one of the previous claims, wherein the metal or metal containing particles comprise magnesium, copper, cobalt, manganese, zinc, iron, silver, platinum, osmium, iridium, palladium, lead, ruthenium, rhodium, gold, chromium, iron, vanadium, cadmium, titanium, zirconium, nobelium, tungsten, thallium or their oxidates and complexes .

9. The conductive polymer composition of any one of the previous claims, wherein the conductive polymer comprises a repeat unit of: aniline, acetylene, pyrrole, phenylene, phenylene vinylene, phenylene ethynylene, phenylene sulfide, fluorene, pyrene, azulene, nathalene, carbazole, indol, thiophene, ethylene dioxy thiophene, or combinations thereof.

10. The conductive polymer composition of any one of the previous claims, wherein the conductive polymer comprises polyaniline.

11. A sensor device comprising: a first electrode and a second electrode, each of the first and second electrodes being in electrical communication via an electrical bridge; wherein the electrical bridge comprises the conductive polymer composition of any one of claim 1-10.

12. The sensor device of claim 11, wherein the conductive polymer composition of the electrical bridge is disposed on the first and second electrodes at a thickness of between 1 micron and 50 microns.

13. The sensor device of any one of claims 11-12, wherein the electrical bridge is configured such that conductive polymer composition changes from the first impedance state to the second impedance in response to the sensor device being exposed to a sterilant.

14. The sensor device of claim 13, wherein the sterilant comprises steam or hydrogen peroxide.

15. The sensor device of any one of claims 11-14, wherein the first and second electrodes are electrically coupled to the electrical bridge such that when the conductive polymer composition is in the first impedance state, a first resistance is measurable across the first and second electrode, and when the conductive polymer composition is in the second impedance state a second resistance is measurable across the first and second electrode, and wherein the first resistance is different than the second resistance.

16. A sterilization system, the system comprising: a sterilizer having a chamber configured to receive medical devices for sterilization; and a sensor device of any one of claims 11-15 disposed in the chamber.

17. A method, the method comprising: providing a sensor device of any one of claims 11 to 15; exposing the sensor device to a sterilant in a sterilization process.

18. The method of claim 17, wherein the sterilant comprises steam or hydrogen peroxide.