Sensor devices

Abstract

The conductive polymer composition comprises a conductive polymer having a first impedance state and a second impedance state different from the first impedance state. The composition further comprises a polymer 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 includes silane treatment.

Description

Technical Field

[0001] Sensor devices useful for sterilization monitoring are described, for example, in U.S. Patent Nos. 8,492,162, 8,353,624, and 8,343,437.

Brief Description of the Drawings

[0002] The present disclosure can be more fully understood by considering the following detailed description of various embodiments of the present disclosure in connection with the accompanying drawings.

[0003] [Figure 1] A sterilization system that can be used in connection with the sensor of the present disclosure is illustrated. [Figure 2] A sensor device according to some embodiments of the present disclosure is shown. [Figure 3] The use of a sensor device in a sterilization system according to some embodiments of the present disclosure is illustrated. [Figure 4] The use of a sensor device in a sterilization system according to some embodiments of the present disclosure is illustrated.

[0004] The drawings identified above may not be drawn to scale and describe various embodiments of the present disclosure, but other embodiments are contemplated as would be described in a form for carrying out the invention. In all cases, the present disclosure describes the invention of the present disclosure by way of illustrative embodiments and not by way of express limitation. Many other variations and embodiments are possible for those skilled in the art, and it should be understood that they are included within the scope and spirit of the present disclosure.

Modes for Carrying Out the Invention

[0005] Chemical indicators are widely used in sterilization monitoring to ensure that the sterilization process has been accurately completed. If the sterilization cycle fails or is inadequate, the patient is put at great risk due to potential cross-contamination from reprocessed surgical instruments.

[0006] Conventional chemical indicators are based on the presence of a particular sterilizer, as well as the color change under its operating conditions, such as sterilization temperature and time. For example, a steam indicator may change color from pale yellow to black. Another type of chemical indicator, known as the Bowie-Dick test pack, is designed to detect air leaks or insufficient air removal within a sterilizer.

[0007] Current practices for visually evaluating chemical indicators require users to visually judge the color change to determine whether the indicator has undergone a proper sterilization process. However, color changes can be subjective. Consequently, a more objective system is highly desirable.

[0008] A system with a more objective basis for evaluating chemical indicators has been described. For example, previous systems utilize a conductive polymer coating solution that can shift from a first impedance state to a second impedance state in response to exposure to a sterilizer. The conductive polymer coating solution of the previous system contains metal particles dispersed in a solution of a conductive polymer and a prepolymer binder material. The metal particles are important components for interaction with the conductive polymer in that they allow redox chemistry to occur when exposed to a sterilizer suitable for consistent, high-sensitivity detection. Furthermore, with respect to such previous coating solutions, it has been found that dispersing metal particles in the coating solution is difficult for industrial applications, especially when added to a solution in a low-density organic solvent, and that uniform dispersion / concentration of particles is important for producing a reproducible coating for chemical indication.

[0009] To facilitate uniform dispersion of particles, blending of particles (e.g., tin nanoparticles) using high-shear mixers has been attempted. However, such mixing processes have been found to present many challenges in terms of manufacturability. Many types of common nanoparticles are aggregated due to electrostatic interactions during the manufacturing process and / or storage, making it extremely difficult to break up the aggregates and redisperse the particles in solution, even with high-energy inputs such as high-shear mixers or ultrasonic mixers. Furthermore, there are several drawbacks to blending nanoparticles into coating solutions using high-shear mixers or ultrasonic mixers. Firstly, the high-energy input generates heat during mixing, creating mechanical shear stress in the reactive coating solution system, which then destabilizes the coating solution and accelerates the gelation of the prepolymer binder. Moreover, the heat and mist generated from high mixing speeds ultimately alter the formulation and pose a health risk to the operator. Secondly, blending powders directly is inefficient. Since typical inorganic nanoparticles are heavy metals and incompatible with organic conductive polymer solutions, the powders are expected to settle rapidly to the bottom and then accumulate at the bottom of the container, even with a high-shear mixer, unless added sufficiently slowly, as opposed to mixing them into the solution. Thirdly, because blending powders is inefficient, some aggregates cannot be separated and dispersed to the desired size. As a result, when the coating solution passes through the in-line filter on the coating line, these nanoparticle aggregates often tend to clog the in-line filter, causing coater failure. Finally, due to the inconsistencies of directly blending powders, such as material sedimentation and loss due to in-line filtration, the actual concentration of nanoparticles in the coating solution can vary significantly from lot to lot, resulting in inconsistent performance of the coating obtained as a chemically labeled composition.

[0010] Finally, while the addition of dispersants can promote particle dispersion, the use of conventional dispersants comes with several drawbacks. For example, dispersing metal nanoparticles in organic solvents requires a considerable amount of dispersant. Many conventional dispersants, such as surfactants, are surface-active compounds and can impart undesirable properties to coating formulations. For instance, dispersants can migrate to the surface, potentially affecting the adhesion of the coating to the substrate or the electrical properties of the coated product. In addition, dispersants often alter the vapor / water penetration properties of the solution, which affects vapor detection capabilities and product stability during long-term storage.

[0011] Therefore, compositions and methods for overcoming the aforementioned problems are desirable.

[0012] Generally, this disclosure relates to compositions and methods comprising a family of silane chemistry as surface modifiers for metal or metal-containing nanoparticles intended to be dispersed in a particular prepolymer coating solution. Such surface modification can promote the gentle (or low-energy) dispersion of nanoparticles in a prepolymer coating solution (even at very low concentrations of the modifying reagent) without adversely affecting the curing chemistry of the solution or the function of the metal or metal-containing nanoparticles.

[0013] With respect to the terms defined below, these definitions shall apply to the entire Specified

[0014] The terms “approximately” or “about” in relation to numerical values ​​or shapes mean + / - 5 percent of a numerical value or characteristic or feature, but explicitly include any narrower range within + / - 5 percent of the numerical value or characteristic or feature, as well as the exact numerical value. For example, a temperature of “approximately” 100°C refers to temperatures between 95°C and 105°C, but explicitly includes any narrower range of temperatures, or even a single temperature within that range, such as exactly 100°C. For example, a viscosity of “approximately” 1 Pa·s refers to a viscosity between 0.95 and 1.05 Pa·s, but explicitly includes a viscosity of exactly 1 Pa·s. Similarly, a “substantially square” perimeter is intended to describe a geometric shape having four side edges, each having a length between 95% and 105% of the length of any other side edge, but also includes a geometric shape where each side edge has exactly the same length.

[0015] With respect to properties or characteristics, the term "substantially" 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 is one that transmits more radiation (e.g., visible light) than a substrate that is not transparent (e.g., absorbs and reflects). Therefore, a substrate that transmits more than 50% of the visible light incident on its surface is substantially transparent, while a substrate that transmits 50% or less of the visible light incident on its surface is not substantially transparent.

[0016] The terms “a,” “an,” and “the” refer to multiple objects unless their content clearly indicates otherwise. Therefore, for example, a reference to a material containing a “compound” includes mixtures of two or more compounds.

[0017] "Appropriate sterilization process" refers to the 10% sterilization of Bacillus subtilis niger. -6 This refers to a sterilization process that achieves a sterility assurance level of 12 log reduction. The sterility assurance level is related to the probability that a sterilized unit remains non-sterile after undergoing the sterilization process.

[0018] "Appropriate environmental conditions" refers to the environmental conditions inside the sterilization chamber that correspond to an appropriate sterilization process.

[0019] The phrase "including at least one of..." following an enumeration means that it includes either any one of the items in the enumeration, or any combination of two or more items in the enumeration.

[0020] The term "impedance" is used, but "impedance" is the reciprocal of "admittance." Depending on the context, a change in the impedance of a material also changes its admittance, so either impedance or admittance can be used.

[0021] The term "and / or" means one or all of the enumerated elements, or any combination of two or more of the enumerated elements.

[0022] All numerical ranges include non-integer values ​​at their endpoints and between them unless otherwise specified (for example, 1-5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0023] Before describing any embodiment of this disclosure in detail, it should be understood that this disclosure is not limited in its application to the details of use, configuration, and arrangement of components described below. Other embodiments of this disclosure are possible and can be implemented or performed in various ways that will be apparent to those skilled in the art. It should also be understood that the expressions and terms used herein are for illustrative purposes only and should not be considered limiting. The use of “including,” “comprising,” or “having” and their variations herein means that they encompass the items listed below and their equivalents, as well as additional items. It should be understood that other embodiments may be utilized and structural or logical modifications may be made without departing from the scope of this disclosure.

[0024] Unless otherwise indicated, all numbers used herein and in the embodiments, such as quantities or components, measured values ​​of properties, etc., should be understood in all cases to be modified by the term “approximately.” Therefore, unless otherwise indicated, the numerical parameters described in the foregoing specification and the appended list of embodiments may vary depending on the desired properties that a person skilled in the art would seek to obtain using the teachings of this disclosure. Each numerical parameter should be interpreted, at least with regard to the number of significant figures reported, by applying ordinary rounding techniques, not as an attempt to limit the application of the doctrine of equivalents to the scope of the claimed embodiments.

[0025] In some embodiments, the present disclosure relates to a sterilization system having a sterilant-responsive switch that can respond to environmental conditions (including the presence of a sterilant such as steam) in a sterilization process and a related sensor device. Generally, the sensor devices of the present disclosure enable the electronic reporting of information regarding each sterilization cycle (e.g., pass / fail information, approval / rejection information), avoiding subjective judgments that can lead to errors (e.g., color changes perceptible to the human eye). Also, the systems and devices of the present disclosure enable the digitization of sterilization results, which will, in turn, free technicians from manual documentation and physical memory.

[0026] FIG. 1 shows a sterilization system 100 in which the sensor device of the present disclosure can be used. As shown in FIG. 1, the sterilization system 100 may include a chamber 110 that can direct a sterilant stream 120. The sterilization system 100 may be of the type commonly used by hospitals and other medical facilities to sterilize reusable medical devices. Various types of sterilization systems 100 can be used for the purposes of the present disclosure. For example, the sterilization system 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 sterilization systems that use hydrogen peroxide as a sterilant are commercially available from Steris (Mentor, OH) or Tuttnauer (Israel). Examples of sterilizers that use steam as a sterilant are commercially available from Steris (Mentor, OH) or Getinge (Gothenburg, Sweden).

[0027] In some embodiments, the chamber 110 can have one or more environmental conditions. The environmental conditions can relate to the conditions inside 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 prior to the sterilization process, and a second environmental condition can exist during the sterilization process.

[0028] In some embodiments, this disclosure relates to a sensor device configured to determine whether a sterilization process within a sterilization system has been carried out in accordance with predetermined guidelines, or whether an appropriate sterilization process has been achieved. An appropriate sterilization process may vary depending on the sterilizer used, the manufacturer of the sterilizer, or the articles being sterilized. For example, the Guideline for Disinfection and Sterilization in Healthcare Facilities, Center for Disease Control (2008), which is incorporated herein by reference in its entirety, provides minimum cycle times for sterilization of various article types and sterilizers.

[0029] Referring to Figure 2, a sensor device 130 according to several embodiments of the present disclosure is shown. The sensor device 130 may include a first electrode 135, a second electrode 140 (sometimes collectively referred to as an electrode pair), and a sterilizer-responsive electric bridge 145 that can facilitate electrical communication between the first electrode 135 and the second electrode 140. In some embodiments, the first electrode 135 and the second electrode 140 may communicate or be electrically coupled via the sterilizer-responsive electric bridge 145 (either via physical contact or via an intermediate such as a conductive member (e.g., a conductive wire)).

[0030] As shown in Figure 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 sterilizer-responsive electrical bridge 145. For example, the electrical bridge 145 may be deposited on the first electrode 135 and the second electrode 140, forming a layer of material spanning them. In such embodiments, the electrical bridge may be deposited or coated on the first electrode 135 and the second electrode 140 with a thickness of 0.1 to 100 microns, 1 to 50 microns, or 5 to 25 microns.

[0031] In some embodiments, in the absence of the sterilizer-responsive electrical bridge 145, the electrode pairs 135, 140 may not be able to communicate electrically (i.e., the electrodes are not in physical contact or are separated by at least a certain distance, and there is no electrical communication without an intervening conductive member such as the electrical bridge 145).

[0032] In some embodiments, the first electrode 135 and the second electrode 140 may include metals such as aluminum, iron, zinc, tungsten, molybdenum, tin, nickel, copper, or alloys thereof, or carbon black, graphene, carbon nanotubes, or conductive polymers.

[0033] In some embodiments, the electric bridge 145 may be configured to have a first impedance state (e.g., high impedance / no conductivity or low conductivity) and a second impedance state that is significantly different from the first impedance state (e.g., low impedance / high conductivity (or vice versa)). For example, in some embodiments, in the first state, the electric bridge exhibits low impedance, and in the second state, it exhibits high impedance (relative to the low impedance state). In some alternative embodiments, in the first state, the electric bridge exhibits low capacitance, and in the second state, it exhibits high capacitance (relative to the low capacitance state), or vice versa.

[0034] In some embodiments, with further reference to Figure 2, the electrical bridge 145 may include a conductive polymer composition configured to exhibit the first and second impedance states described above. In some embodiments, the conductive polymer composition of the present disclosure may be a composite material comprising a conductive polymer, one or more types of surface-modified metals or metal-containing particles, and a polymer binder.

[0035] Generally, the conductive polymer in a conductive polymer composition may be any polymer material that is shiftable between a first impedance state and a second impedance state. In some embodiments, a suitable conductive polymer may be capable of being converted from a first impedance state to a second impedance state in response to changes in environmental conditions (e.g., transitioning from a first state to a second state upon contact with a sterilizer, or transitioning from a first state to a second state when a suitable sterilization process is achieved in a sterilizer system). In some embodiments, the first state may be a low impedance state and the second state may be a high impedance state (or vice versa). In some embodiments, the low impedance state may be a doped (e.g., acid-doped) conductive state and the high impedance state may be a dedoped (e.g., by inclusion and activation of a basic material) nonconductive (or at least less conductive than the conductivity of the conductive state). In some embodiments, the low impedance state refers to a state having sufficient admittance to electrically bridge an open circuit, e.g., having an admittance of at least 2 Siemens.

[0036] In some embodiments, the conductive polymer of the conductive polymer composition may have repeating units of aniline, acetylene, pyrrole, phenylene, phenylenevinylene, phenyleneethynylene, phenylene sulfide, fluorene, pyrene, azulene, naphthalene, carbazole, indole, thiophene, ethylenedioxythiophene, or combinations thereof. The conductive polymer material can be doped or undoped with various dopants such as dinonylnaphthalenesulfonic acid (DNNSA), dodecylbenzenesulfonic acid (DBSA), arsenic pentafluoride, triiodide, camphor sulfonate, methanesulfonic acid, halogen or polyhalogen ions, methanol, bisulfate, hydrochloric acid, tetrafluoroborate, sodium sulfite, or combinations thereof.

[0037] In some embodiments, the conductive polymer in a conductive polymer composition may contain (or essentially consist of) polyaniline (PANI). In some embodiments, the conductive PANI is in the form of an electrolyte, a polyelectrolyte, or a PANI salt, which can be readily achieved by acid doping of PANI. PANI can be one of three oxidation states (leucoemeraldine, emeraldine (in salt or base form), and per(niguluaniline)). Emeraldine is nonconductive in its base form and can be conductive in its polyelectrolyte or salt form. Emeraldine salts can be converted to nonconductive leucoemeraldine salts or per(niguluaniline) via redox reactions. Conductive polymers can be converted to nonconductive polymers via dedoping reactions. In some embodiments, the conductive polymer material of the present disclosure may initially exist in emeraldine salt form and be convertible to leucoemeraldine salt form upon exposure to a sterilizing agent.

[0038] In some embodiments, the conductive polymer may be present in the conductive polymer composition (or composite material forming the electrical bridge 145) in an amount of at least 5% by weight, at least 10% by weight, at least 30% by weight, at least 50% by weight, or at least 90% by weight, based on the total weight of the conductive polymer composition (or composite material forming the electrical bridge 145).

[0039] In some embodiments, suitable metals or metal-containing particles may include conductive metal particles. Additionally or alternatively, in some embodiments, metal particles can be characterized as redox particles (i.e., particles that facilitate chemical reactions within the electrical bridge 145 in the presence of a sterilizer (e.g., steam), involving the loss of one or more electrons by one molecule (oxidation - metal redox particle) and simultaneous gain by another molecule (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, tin may be given as a metal particle. In some embodiments, suitable metal particles may include metal alloys such as silver-tin alloys, gold-tin alloys, or indium-tin alloys.

[0040] In some embodiments, useful metal redox particles may be capable of releasing electrons when exposed to a sterilizing agent (e.g., vapor). For example, suitable metal redox particles may include those that, when activated, release electrons and can reduce PANI electrolytes or polymer electrolytes (in protonated form) to their leucoemeraldine salt form. An example of such a mechanism is as follows:

[0041] [ka] That is correct.

[0042] In some embodiments, suitable metals or metal-containing particles may include conductive metal particles, nonconductive metal oxides, metal complexes, or combinations thereof, which can be characterized as catalyst particles (i.e., particles that catalyze chemical reactions within the electrical bridge 145 in the presence of a sterilizer (e.g., hydrogen peroxide), with the formation of by-products that increase the local pH 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 oxides and complexes thereof. In some embodiments, suitable metal-containing catalyst particles may include magnesium oxide, iron oxide, manganese oxide, zinc oxide, iron oxide, potassium dichromate, vanadylacetylacetonate, 1:1 copper(II)-, manganese(II)-, cobalt(II)-, or nickel(II)-hexamine complexes. In some embodiments, the preferred metal catalyst particles may include copper.

[0043] In some embodiments, useful metal catalyst particles may include those capable of catalyzing a reaction with a sterilizing agent (e.g., hydrogen peroxide) to produce hydroxide anions and water as byproducts. The presence of hydroxide anions then increases the local pH near the conductive polymer, which leads to proton capture and neutralization of the PANI electrolyte or polymer electrolyte (protonated form) to its neutral or low-protonated emeraldine form. An example of such a set of reactions (using hydrogen peroxide as the sterilizing agent) is as follows:

[0044] [ka] That is correct.

[0045] In some embodiments, useful metals or metal-containing particles may include those that, when activated by a sterilizing agent (e.g., vapor or hydrogen peroxide), can generate free electrons, hydrides, or hydrogen that can reduce a conductive polymer from a first conductive state to a second conductive state (e.g., converting PANI from an emeraldine salt (ES) state to a leucoemeraldine salt (LS) state). An example of such a set of reactions is given below:

[0046] [ka] The (imbalance formula) is shown below.

[0047] As described above, in some embodiments, metal or metal-containing nanoparticles may be treated with a surface treatment agent to facilitate the dispersion of particles in the coating solution. Generally, such a surface treatment agent may have a first end that adheres to the particle surface (covalently, ionically, or via strong physicoadsorption) and a second end that imparts compatibility between the particles and the coating solution. In some embodiments, the surface treatment agent may include silane. Surface modification can be achieved either following or after mixing in the coating solution. In some embodiments, the silane surface treatment agent may be reacted with the particle or nanoparticle surface before being incorporated into the coating solution. The amount of surface modifier may depend on factors such as particle size, particle type, modifier molecular weight, and modifier type. Generally, a single layer of modifier is deposited on the surface of the particles. The required deposition procedure or reaction conditions also depend on the surface modifier used. In the case of silane, the surface treatment can be carried out under acidic or basic conditions, at high temperature, for a period of about 1 to 24 hours.

[0048] In some embodiments, preferred silane surface treatment agents include isooctyltrimethoxysilane, N-(3-triethoxysilylpropyl)methoxyethoxyethoxyethyl carbamate (PEG3TES), SILQUEST® A1230, N-(3-triethoxysilylpropyl)methoxyethoxyethoxyethyl carbamate (PEG2TES), 3-(methacryloyloxy)propyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-(methacryloyloxy)propyltriethoxysilane, 3-(methacryloyloxy)propylmethyldimethoxysilane, 3-(acryloyloxypropyl)methyldimethoxysilane, 3-(methacryloyloxy)propyldimethylethoxysilane, 3-(methacryloyloxy)propyldimethylethoxysilane, vinyldimethylethoxysilane, and It may contain one or any combination of two or more of the following: sobutyltrimethoxysilane, (3,3,3-trifluoropropyl)trimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, vinylmethyldiacetoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris-isobutoxysilane, vinyltriisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, styrylethyltrimethoxysilane, mercaptopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. In some embodiments, suitable silane surface treatment agents may include one or any combination of two or more of vinyldimethylethoxysilane, isobutyltrimethoxysilane, 3,3,3-trifluoropropyl)trimethoxysilane, n-octyltrimethoxysilane, and propyltrimethoxysilane.

[0049] In some embodiments, a suitable silane surface treatment agent may include one or any combination of two or more fluorinated or non-fluorinated short-chain alkyltrimethoxysilane or dimethoxysilane compounds having 1 to 8 carbon atoms.

[0050] In some embodiments, the surface modifier may be added to the particles at extremely low concentrations. For example, the surface modifier may be added to the particles in amounts of 0.005% to 5% by weight, or 0.02% to 0.5% by weight, based on the total weight of the nanoparticles. It has been found that even at such low concentrations of the surface modifier, the functionality of the particles (e.g., redox properties) is maintained, while the curing of the prepolymer binder component of the coating solution is not affected.

[0051] In some embodiments, the surface modifier can cover the surface area of ​​the particles in an average amount of 5% to 100%, 10% to 90%, or 40% to 80%, based on the total surface area of ​​the particles.

[0052] In some embodiments, the surface-modified metal or metal-containing particles may be nanoparticles. In this regard, the particles may have an average size (with respect to the average longest dimension) of 0.01 microns to 0.1 microns or 0.001 microns to 1 micron, or 5 microns or less, or 250 nanometers (nm) or less, or 200 nm or less. In some embodiments, the surface-modified metal or metal-containing particles may be spherical, non-spherical, or a combination thereof.

[0053] In some embodiments, the surface-modified metal or metal-containing particles may be present in the conductive polymer composition (or composite material forming the electrical bridge 145) in amounts of at least 0.01% by weight, at least 0.1% by weight, at least 1.0% by weight, at least 5% by weight, or at least 20% by weight, based on the total weight of the conductive polymer composition (or composite material forming the electrical bridge 145); or in amounts of 0.1% to 30% by weight, 0.5% to 20% by weight, 0.5% to 10% by weight, or 1% to 15% by weight, based on the total weight of the conductive polymer composition (or composite material forming the electrical bridge 145). Generally, the amount of metal or metal-containing particles present in the electrical bridge may be the amount necessary to convert the conductive polymer from a first impedance state to a second impedance state (acidic state) when exposed to a sterilizer.

[0054] In some embodiments, the conductive polymer compositions of the present disclosure may include a polymer binder. Suitable polymer binders may include polyurethane, polyvinyl butyral, polyacrylate, polyvinyl acetate, polystyrene, polystyrene acrylate, polyurea, polyimide, amide, epoxy, glycidyl-Si-Zr-containing sol gel, polyester, phenoxy resin, polysulfide, or mixtures thereof.

[0055] In some embodiments, the polymer binder may be present in the electrical bridge 145 in amounts of at least 5% by weight, at least 10% by weight, at least 40% by weight, at least 50% by weight, or at least 90% by weight, based on the total weight of the conductive polymer composition (or composite material forming the electrical bridge 145); or in amounts of 5% to 99% by weight, 10% to 95% by weight, 20% to 95% by weight, or 40% to 95% by weight, based on the total weight of the conductive polymer composition (or composite material forming the electrical bridge 145).

[0056] In some embodiments, the conductive polymer compositions of the present disclosure can be formed by drying a prepolymer solution which is a solvent dispersion of the above-mentioned conductive polymer, a polymer binder in a prepolymer (curable) form, and surface-modified nanoparticles.

[0057] In some embodiments, the conductive polymer may be present in the prepolymer solution in amounts of 5% to 60% by weight, 10% to 50% by weight, or 20% to 40% by weight, based on the total weight of the prepolymer solution.

[0058] In some embodiments, the polymer binder in prepolymer (curable) form may be present in the prepolymer solution in amounts of 1% to 100% by weight, 20% to 80% by weight, or 30% to 70% by weight, based on the total weight of the prepolymer solution. In some embodiments, the polymer binder in prepolymer (curable) form may be curable by thermal curing or electromagnetic radiation curing (e.g., UV light).

[0059] In some embodiments, the solvent dispersion may contain a solvent and surface-modified nanoparticles. Suitable solvents may include xylene, heptane, hexane, MIBK, ethyl acetate, butyl acetate, toluene, or combinations thereof. The solvent may be present in the solvent dispersion in amounts of 50% to 99% by weight, 40% to 80% by weight, or 50% to 70% by weight, based on the total weight of the solvent dispersion. The surface-modified nanoparticles may be present in the solvent dispersion in amounts of 10% to 99% by weight, 40% to 80% by weight, or 50% to 70% by weight, based on the total weight of the solvent dispersion.

[0060] In some embodiments, the solvent dispersion may be present in the prepolymer solution in amounts of 0.1% to 20% by weight, 0.5% to 10% by weight, or 1% to 5% by weight, based on the total weight of the prepolymer solution.

[0061] In some embodiments, the disclosure further relates to a method for producing the above-mentioned prepolymer solution. This method may include preparing a first composition comprising a conductive polymer and a polymer binder in a prepolymer (curable) form. The method may then include preparing a second composition (a pre-dispersed particle solution) comprising surface-modified particles and a solvent. The method may then include mixing the first composition and the second composition (for example, gently mixing them via a magnetic mixer or mechanical blender) to form the above-mentioned prepolymer solution.

[0062] To overcome some of the manufacturing and consistency problems described above, it was discovered that particles could be successfully dispersed in high-concentration solutions by modifying them in the solvent using the silane chemistry described above. Subsequently, by gently mixing the pre-dispersed solvent system into a composition containing a conductive polymer and a prepolymer binder without using strong blending forces, highly consistent performance was achieved for coatings produced from the deposition of the prepolymer coating solution of this disclosure. The use of pre-dispersed particles also improved the pot life of the coating solution, thereby effectively avoiding unexpected sudden gelation of the coating solution during the coating process, which can be a cause of coating line failure due to blockages in process equipment (e.g., coating heads, pumps, pipes, etc.).

[0063] In some embodiments, the electrical bridge 145 may exhibit a change in color depending on the change in impedance state. For example, in embodiments in which the electrical bridge 145 includes PANI, the electrical bridge 145 may start in a first impedance state having a first color (e.g., green) and in a second impedance state having a second color (e.g., blue or yellow). In this way, the validity of the sterilization cycle can be visually determined.

[0064] In some embodiments, during the deposition and / or curing of the prepolymer solution, the surface-modifying particles of the present disclosure can 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 part of the composite material does not change by more than 40%, more than 25%, more than 10%, or more than 5% compared to any second different part of the composite material.

[0065] In some embodiments, during the deposition and / or curing of the prepolymer solution, the conductive polymer, polymer binder, and surface-modifying particles can 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 part of the composite material does not change by more than 20%, more than 15%, more than 10%, or more than 5% compared to any second different part of the composite material.

[0066] Referring now to Figure 3, the use of a sensor device 130 in a sterilization system 100 according to some embodiments of the present disclosure is illustrated. As shown, the sensor device 130 may be located inside the chamber 110 of the sterilization system 100. In some embodiments, the sensor device 130 may be located inside the chamber 110 so that it can interact with components of the sterilizing agent flow 120 once it enters the chamber 110.

[0067] In some embodiments, the sensor device 130 may be a standalone device that can be placed within the sterilization system 100. In further embodiments, the sensor device 130 may be incorporated into another device (e.g., a sterilization process challenge device having a meandering pathway such as a porous matrix or luminal channel, such as a Bowie-Dick test pack) which may include a housing and one or more internal components or materials configured to facilitate the assurance that appropriate sterilization conditions are present during the sterilization cycle.

[0068] In some embodiments, a reader device 160 may also be provided. The reader device 160 may be configured to receive a signal from the sensor device 130 and convert the received signal into a determination regarding the validity of the sterilization cycle (e.g., pass / fail determination). For example, the reader device 160 may be configured to query the sensor device 130 to measure the impedance between electrode pairs (e.g., individual readings, or continuous or semi-continuous readings over time) that can correspond to whether various environmental conditions have been achieved in the sterilization process or whether a suitable sterilization process has been achieved. In some embodiments, when exposed to a first environmental condition (e.g., ambient conditions), the reader device 160 (if querying the sensor device) measures a first impedance value indicating whether the conductive polymer of the electrical bridge 145 is in a first impedance state or a second impedance state. As described above, changes in the environmental conditions within the chamber 110 (or second environmental conditions) can change the impedance state of the conductive polymer, and subsequently change the impedance between the electrode pairs measured by the reader device 160. In some embodiments, when the conductive polymer is in a first impedance state, a first resistance is measurable between the first and second electrodes, and when the conductive polymer is in a second impedance state, a second resistance is measurable between the first and second electrodes, and the first resistance is different from the second resistance.

[0069] In some embodiments, the reader device 160 may communicate electronically with the sensor device 130 (continuously or at any desired intervals) (or may be capable of electronic communication) (e.g., wireless communication such as Bluetooth, RF, or short-range wireless communication, or wired communication via a suitable electronic connection (e.g., a pair of electrical leads that can be coupled to the 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).

[0070] Referring now to Figure 4, the use of a sensor device 130 in a sterilization system 100 according to several embodiments of the present disclosure is illustrated. As shown, the sensor device 130 may be placed again within the chamber 110 of the sterilization system 100 so that it can interact with the components of the sterilizing agent flow 120 once it enters the chamber 110. Furthermore, one or more medical devices 165 to be sterilized may be placed together with the chamber 110. For example, as shown, the sensor device 130 and one or more medical devices 165 may be housed together in a package 170 (often referred to in the industry as a tray). It should be understood that each package 170 can house any number of medical devices 165 or any number of sensor devices 130. Alternatively, the sensor device 130 and one or more medical devices 165 may be housed separately within the chamber 110. As shown, in embodiments, a reader device 140 may also be provided.

[0071] In some embodiments, the disclosure further relates to a method of using a sensor device 130 in a sterilization system 100. This method may begin with a user placing the sensor device 130 inside a chamber 110. As previously stated, the sensor device 130 may be placed alone inside the chamber 110, or together with one or more medical devices to be sterilized (and may be packaged in a tray together with the medical devices, or may be placed inside the chamber 110 separately from the medical devices or medical device tray). After the sensor device is placed inside the chamber, the chamber 110 can be sealed from the environment.

[0072] In some embodiments, the user can then initiate the sterilization process of the sterilizer, exposing the sensor device to the sterilizer and / or one or more environmental conditions during the sterilization process. For example, if the sterilizer is vapor, the sterilizer may be at least 95% saturated vapor / water vapor, and the sterilization process may include raising the temperature inside the chamber 110 to at least 132 degrees Celsius 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 sterilizer is hydrogen peroxide, the sterilizer may be in an atmosphere containing at least 30% hydrogen peroxide vapor, and the sterilization process may be carried out at at least 50 degrees Celsius for at least 60 minutes. Various standards may exist for each sterilizer, which may vary depending on the manufacturer, the articles being sterilized, or a combination thereof.

[0073] In some embodiments, as described above, exposure of the sensor 130 to a sterilizing agent and / or the conditions within the chamber 110 may result in a change in the impedance state of the conductive polymer of the electrical bridge 145.

[0074] In some embodiments, this method may further include the reader device 160 receiving signals from the sensor device 130 continuously, intermittently, or at any desired time, and converting such received signals into a determination regarding the validity of the sterilization cycle (e.g., pass / fail determination). As described above, the received signals may relate to the measured impedance between electrode pairs, which corresponds to various environmental conditions achieved or not achieved in the sterilization process. For example, a measured impedance above or below a predetermined value can be used to determine whether appropriate sterilization process conditions have been achieved in the chamber 110. [Examples]

[0075] These examples are for illustrative purposes only and are not intended to limit the scope of the appended claims. All parts, percentages, ratios, etc., in the examples and the remainder of the specification are by weight unless otherwise noted. The solvents and other reagents used were obtained from Fujifilm Wako Pure Chemical Corporation or Sigma-Aldrich Chemical Company; Milwaukee, Wisconsin. The following abbreviations are used: mm = millimeter, mL = milliliter, in = inch, g = gram, mg = milligram, kg = kilogram, hrs = hour, nm = nanometer.

[0076] [Table 1]

[0077] Example 1 Preparation of C8-silane samples: Four portions of octyltrimethoxysilane (C8) were weighed into 20 mL glass vials at weights of 12.6, 26, 50, and 111 mg. Then, 13.6 g of 1:1 (weight / weight) xylene and MIBK were added to each vial and mixed thoroughly. 2.4 g of tin nanoparticles were added to each resulting solution, and the mixture was then sonicated in an ultrasonic bath for 2 hours.

[0078] Preparation of PEG-silane samples: The same procedure as for C8-silane was followed. Two samples were prepared using 20 mg and 48 mg of PEG-silane to create a 15% tin concentration.

[0079] Preparation of C1-silane and vinyl-silane samples: Using 50 mg of C1, a 15% tin concentration was prepared following the same procedure as for C8-silane.

[0080] The control sample was prepared without any dispersant by adding 2.4 grams of tin nanoparticles to 13.6 1:1 (mW / mW) xylene / MIBK and sonicating for 2 hours.

[0081] All samples were left to stand on a benchtop for 48 hours, and the sedimentation behavior of the particles was observed. The results are shown in Table 2.

[0082] [Table 2]

[0083] Example 2 60 grams of tin nanoparticles were pre-dispersed in 340 g of 1:1 (mW / mW) xylene / MIBK by sonication for 2 hours, followed by the addition of 0.15 g of TMFS, and sonication was continued at 40°C for 2 hours. A control sample was prepared using the same procedure without the use of a modified compound. The samples were left standing on a benchtop, and particle sedimentation was observed for 2 weeks. The particle dispersion characteristics are shown in Table 3.

[0084] [Table 3]

[0085] Example 3 60 grams of tin nanoparticles were mixed with 170 g of xylene and 170 g of MIBK. The mixture was shaken manually several times, then 0.3 g of TFMS was added, and the mixture was shaken again. The resulting suspension was transferred to a jacketed beaker at a circulating temperature of 40°C. The suspension was stirred with a magnetic stirring rod to create a vortex suspension. An ultrasonic treatment head was placed in the solution, and the suspension was ultrasonically treated. Approximately 2 mL of the sample solution was collected at 0.5 hours and 1 hour. Each sample was diluted to 1% with a 1:1 xylene / MIBK ratio for particle analysis using a Horiba particle analyzer. Table 4 shows the particle analysis data for 0.5 hours of ultrasonic treatment, and Table 5 shows the data for 1 hour of ultrasonic treatment.

[0086] [Table 4]

[0087] [Table 5]

[0088] Tables 4 and 5 show that the majority of the particles were 1 micron in size (approximately 56%). However, after 1 hour of sonication, nearly 98% of the particles were converted to approximately 150 nm, with only 2% being around 5 microns.

[0089] Example 4 60 grams of tin nanoparticles were mixed with 170 g of xylene and 170 g of MIBK. The mixture was shaken manually several times, then 0.3 g of TFMS was added, and the mixture was shaken again. The resulting suspension was transferred to a jacketed metal beaker at a circulating temperature of 40°C. The suspension was mixed for 4 hours at 10,000 rpm using an Omni Ultra Shear homogenizer (Lab M Model). Samples were taken from the concentrated suspension, diluted with 1:1 xylene / MIBK, and the particle size distribution was determined using a Horiba particle analyzer. Table 6 shows the particle distribution after 4 hours of homogenization. 100% of the tin nanoparticles were converted to a size of less than 80 nm. The 15% suspension solution was diluted to 3% with a 1:1 xylene / MIBK solvent mixture and passed through a 10 microliter polypropylene filter (VWR). The solid content of the resulting filtrate was determined by evaporating the solvent at 150°C for 2 hours. Samples without TFMS were sonicated with 3 wt% tin nanoparticles in a 1 / 1 xylene / MIBK solvent mixture for 20 minutes and used as a control. Table 7 shows the final filtration effect and final solid content.

[0090] [Table 6]

[0091] [Table 7]

[0092] Example 5 A coating solution containing polyaniline and polyurethane was prepared as shown in Table 8. Before coating, the solution was stirred for 1 hour with a small magnetic stirring rod. To this solution, a 15% TFMS-modified tin solution was added to the PANI / PU mixture in a 1:10 ratio and gently mixed with the magnetic stirring rod prepared through Examples 1 and 3. Using a control sample, tin nanoparticles were directly added at 1.5% of the total solution and sonicated for 20 minutes. The solution was coated onto silver / carbon printed open circuits (Molex LLC, Naperville, IL) using a #16 Mayer bar, and then cured at 140°C for 4 minutes to achieve a tin concentration of approximately 6.93% in the final coating film. This coated silver / carbon printed open circuit was mounted on blotting paper cards from a 3M Comply Bowidic test pack to provide silver circuit cards. The initial electrical resistance of the coated silver printed open circuit was measured with a multimeter.

[0093] [Table 8]

[0094] A commercially available COMPLY Bowie-Dick test pack (3M Company, St. Paul, MN) was carefully opened by cutting a slit along the tip of the packaging paper located beneath the label stock. This test pack consists of one pack or one deck of blank blotting paper cards, with a Bowie-Dick chemical indicator card in the center of the blank blotting paper cards, all of which are wrapped in paper. Two of the original blotting paper cards in the opened Bowie-Dick test pack were replaced using silver circuit cards. One silver circuit card (card 1) was replaced with the fifth card preceding the chemical indicator card, and another silver circuit card (card 2) was replaced with the card immediately following the chemical indicator card. The chemical indicator card was left in its original position. This modified card stack was repackaged in its original packaging paper and sealed with a small piece of SCOTCH tape (3M Company, St. Paul, MN) to close the opening on the label stock.

[0095] The modified Bowie-Dick test pack was then subjected to a Bowie-Dick test cycle in an AMSCO Eagle 3013 steam sterilizer (Steris plc, Mentor, OH) at 132°C for 3.5 minutes. After the Bowie-Dick test cycle was completed, the test pack was opened, the silver circuit card was removed, and the conductivity of the installed circuit was measured with a multimeter. The results of the electrical resistance measurements are shown in Table 9. The results showed that the silver circuit coated with lithium carbonate-doped PANI could function as an electrochemical indicator in the air removal test.

[0096] [Table 9]

[0097] Example 6 Five samples of 17.5 wt% tin nanopowder dispersed in 1:1 xylene / MIBK were prepared. Silane was added to these dispersions in the amounts indicated. The dispersions were then sonicated overnight at room temperature. Dispersion stability was monitored over time, and the results are shown in Table 10. Stability refers to the time until significant sedimentation occurs.

[0098] [Table 10]

[0099] Example 7 Five samples of 17.5 wt% tin nanopowder dispersed in 1:1 xylene / MIBK were prepared. Silane was added to these dispersions in the amounts indicated. The dispersions were then sonicated at 40°C for 1.5 hours. Dispersion stability was monitored over time. Water in methanol (1:9 H2O:MeOH) was added to the samples in the amounts indicated, the samples were vortexed and mixed, and then sonicated again at 40°C for 1.5 hours. Dispersion stability was again monitored over time, and the results are shown in Table 11. Stability refers to the time until significant sedimentation occurs.

[0100] [Table 11]

[0101] Example 8 Five samples of 17.5 wt% tin nanopowder dispersed in 1:1 xylene / MIBK were prepared. To these dispersions, silane in methanol and water (1:9 H2O:MeOH) were added in the amounts indicated. The dispersions were vortexed and mixed, and then sonicated at 40°C for 1.5 hours. Dispersion stability was monitored over time, and the results are shown in Table 12. Stability refers to the time until significant sedimentation occurs.

[0102] [Table 12]

[0103] Example 9 Samples A, B, and D described in Experiment 3 were separately mixed with the PAN / PU solution described in Experiment 5 in the weight ratios shown in the table below. The resulting mixtures were vortexed for 30 seconds and then sonicated for 2-3 hours. The tin particles were well dispersed in the solution. The solution was left on a bench to allow the particles to remain dispersed in the solution for at least 2 hours, and the results are shown in Table 13. Stability refers to the time until significant sedimentation occurs.

[0104] [Table 13]

[0105] Example 10 Four 3kg lots of each of the coating solutions provided in Table 10 were prepared without tin. After preparing the solutions, 45g of tin (by total mass) was slowly added to the PANI / PU solution using a high-shear mixer, and mixing was continued for 20 minutes. This solution was mixed again for another 20 minutes using a high-shear mixer immediately before coating, and then transferred to a coating sump, where the solution was continuously stirred using an air mixer. The solution was passed through a 50-micrometer in-line filter and then through a coating die to coat the PET surface. After coating was complete, the tin concentration in a portion of the lots recovered from the coating sump was determined by inductively coupled plasma spectroscopy. Table 14 contains the observations from each experiment.

[0106] [Table 14]

[0107] Example 11 Six grams of copper nanoparticles were mixed with 17 g of xylene and 17 g of MIBK. The mixture was shaken manually several times, then 0.03 g of TFMS was added and shaken again. The resulting suspension was sonicated overnight at 40°C. This suspension was then diluted to 1% with a 1 / 1 xylene-MIBK solvent mixture and passed through a 10-micrometer filter. This 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 could not 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 approximately 52 nm and 18% to approximately 335 nm.

[0108] [Table 15]

[0109] Example 12 Polyaniline and polyurethane coating solutions were prepared as shown in Table 16. Before coating, the solutions were stirred for 1 hour using a small magnetic stirring rod. To separate a portion of the solution, TFMS-modified 10% and 5% copper solutions were added to the PANI / PU mixture in a 1:10 ratio and gently mixed using a magnetic stirring rod. The tin concentrations in the dried films coated with the 10% and 5% copper stock suspensions were 4.73% and 2.42%, respectively. A control sample coating without copper was also prepared using the same volume of 1:1 xylene / MIBK solution. Silver / carbon printed open circuits (Molex LLC, Naperville, IL) were coated with each solution using a #16 Mayer bar, and the coatings were cured at 140°C for 6 minutes. Each coated silver / carbon electrode pair was exposed to hydrogen peroxide vapor using an ASP 100S sterilizer. The initial and final electrical resistances of each coated silver printed open circuit were measured with a multimeter. Table 17 shows the resistance changes of the copper nanoparticle-doped polyaniline conductive layer and the control coating before and after exposure to hydrogen peroxide.

[0110] [Table 16]

[0111] [Table 17]

Claims

1. A conductive polymer having a first impedance state and a second impedance state different from the first impedance state, Polymer 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 includes silane treatment, A conductive polymer composition containing [a specific component].

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

3. The conductive polymer composition according to claim 1 or 2, wherein the surface-modified metal or metal-containing particles are present in the conductive polymer composition in an amount of 0.5% to 10% by weight, based on the total weight of the conductive polymer composition.

4. The conductive polymer composition according to any one of claims 1 to 3, wherein the polymer binder is present in the conductive polymer composition in an amount of 40% to 95% by weight, based on the total weight of the conductive polymer composition.

5. The conductive polymer composition according to any one of claims 1 to 4, wherein the conductive polymer, polymer binder, and surface-modified particles are uniformly dispersed in the conductive polymer composition.

6. The conductive polymer composition according to any one of claims 1 to 5, wherein the surface-modified particles are uniformly dispersed in the conductive polymer composition.

7. The conductive polymer composition according to any one of claims 1 to 6, wherein the metal or metal-containing particles include 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 according to any one of claims 1 to 7, wherein the metal or metal-containing particles comprises 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 oxides and complexes thereof.

9. The conductive polymer composition according to any one of claims 1 to 8, wherein the conductive polymer comprises repeating units of aniline, acetylene, pyrrole, phenylene, phenylenevinylene, phenyleneethynylene, phenylene sulfide, fluorene, pyrene, azulene, naphthalene, carbazole, indole, thiophene, ethylenedioxythiophene, or combinations thereof.

10. The conductive polymer composition according to any one of claims 1 to 9, wherein the conductive polymer comprises polyaniline.

11. A sensor device comprising a first electrode and a second electrode, each of which communicates electrically via an electrical bridge, The electric bridge comprises the conductive polymer composition described in any one of claims 1 to 10. Sensor device.

12. The sensor device according to claim 11, wherein the conductive polymer composition of the electric bridge is arranged on the first and second electrodes to a thickness of 1 micron to 50 microns.

13. The sensor device according to claim 11 or 12, wherein the electrical bridge is configured such that the conductive polymer composition changes from a first impedance state to a second impedance in response to the sensor device being exposed to a sterilizing agent.

14. The sensor device according to claim 13, wherein the sterilizing agent includes vapor or hydrogen peroxide.

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

16. The system includes a sterilizer having a chamber configured to accept medical devices for sterilization, and A sterilization system comprising a sensor device according to any one of claims 11 to 15, disposed within the chamber.

17. To provide a sensor device according to any one of claims 11 to 15, Exposing the sensor device to a sterilizing agent during the sterilization process, Methods that include...

18. The method according to claim 17, wherein the sterilizing agent comprises steam or hydrogen peroxide.

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