CN117337199A

CN117337199A - sensor device

Info

Publication number: CN117337199A
Application number: CN202280031732.XA
Authority: CN
Inventors: 夏文胜; 景乃勇; 詹姆斯·A·菲普斯
Original assignee: 3M Innovative Properties Co
Current assignee: Shuwanuo Intellectual Property Co
Priority date: 2021-04-28
Filing date: 2022-03-30
Publication date: 2024-01-02

Abstract

A sensor device includes a first electrode and a second electrode. Each of the first electrode and the second electrode is electrically coupled to a bridge. The bridge includes a conductive polymer having a first impedance state and a second impedance state different from the first impedance state. The bridge comprises a metal or metal-containing particles.

Description

Sensor device

Background

Sensor devices for sterilization monitoring have been described in, for example, U.S. patent nos. 8,492,162, 4,594,223 and 5,204,062.

Disclosure of Invention

In some embodiments, the sensor device may report pass/fail information directly about the sterilization cycle to avoid any subjective human eye color judgment, thereby reducing errors. In addition, digitization of chemical indicators will free people from subjective interpretation, manual recording, and physical storage of results.

In one aspect, the present disclosure provides a sensor device comprising: a sterilant responsive switch, the sterilant responsive switch comprising: a first electrode and a second electrode, each of the first electrode and the second electrode having a first end and a second end, the first end electrically coupled to a circuit; a conductive polymer having a first state and a second state; conductive particles; and a polymeric binder, wherein the conductive polymer is capable of transitioning from a first state to a second state upon contact with a sterilant.

In another aspect, the present disclosure provides a method comprising: providing a sensor device of the present disclosure; exposing the sensor device to a sterilant during sterilization; the sterilant responsive switch is allowed to react with the sterilant thereby changing the sterilant responsive switch from the first state to the second state.

In another aspect, the present disclosure provides a system comprising: the sensor device of the present disclosure; a storage element for storing data captured by the sensor device; and a sensing device configured to interrogate the sensor device.

Various aspects and advantages of exemplary embodiments of the present disclosure have been summarized. The above summary is not intended to describe each illustrated embodiment or every implementation of the present disclosure. Additional features and advantages are disclosed in the following embodiments. The figures and the detailed description that follow more particularly exemplify certain embodiments using the principles disclosed herein.

Definition of the definition

For the following defined terms, unless a different definition is provided in the claims or elsewhere in the specification based on a specific reference to a modified form of the term used in the following definition, the entire specification, including the claims, should be read as if set forth below:

The term "about" or "approximately" with respect to a value or shape means +/-5% of the value or property or characteristic, but also expressly includes any narrow range and precise value within +/-5% of the value or property or characteristic. For example, a temperature of "about" 100 ℃ refers to a temperature from 95 ℃ to 105 ℃, but also explicitly includes any narrower temperature range or even a single temperature within this range, including for example temperatures precisely 100 ℃. For example, a viscosity of "about" 1Pa-sec refers to a viscosity from 0.95Pa-sec to 1.05Pa-sec, but also specifically includes a viscosity of exactly 1 Pa-sec. Similarly, the perimeter of a "substantially square" is intended to describe a geometry having four side edges, wherein each side edge has a length of 95% to 105% of the length of any other side edge, but also includes geometries wherein each side edge has exactly the same length.

The term "substantially" with respect to a characteristic or feature means that the characteristic or feature exhibits a degree that is greater than the degree to which the opposing faces of the characteristic or feature exhibit. For example, a "substantially" transparent substrate refers to a substrate that transmits more radiation (e.g., visible light) than does not transmit (e.g., absorb and reflect). Thus, a substrate that transmits more than 50% of visible light incident on its surface is substantially transparent, but a substrate that transmits 50% or less of visible light incident on 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 comprising "a compound" includes a mixture of two or more compounds.

"ionic salt" refers to any salt having a cation selected from group I, group II metals (especially alkaline earth metals) or post transition metals. Preferably magnesium or bismuth. The anion of the ionic salt may be selected from halogen, oxygen, sulfur, carbonate, borate, titanate, molybdate, phosphate, oxychloride, or a combination thereof.

An "integrated circuit" refers to a component that stores and processes information, and in particular, modulates and demodulates Radio Frequency (RF) signals.

"late transition metal" refers to a group of metallic elements in the periodic table that are located between the left side of the transition metal and the right side of the metalloid. As proposed by Huheey JE, keiter EA and Keiter RL,1993, chapter 14, principles of Structure & Reactivity, 4 th edition, harperCollins College Publishers, ISBN 0-06-042995-X, including Ga, in, tl, sn, pb, bi, al, ge, sb, po.

"second substrate location" refers to a location on the substrate that indicates adequate sterilization. May be established in part by the wicking substrate.

"conductive element" refers to the ability to conduct electrical current. The conductive material has a conductivity of at least 2 siemens per centimeter. Exemplary conductive elements include silver, gold, copper, aluminum, carbon black, or combinations thereof.

"monitoring loop" refers to an open or closed electrical loop.

"sufficient sterilization process" means that a level of sterilization assurance of 10 can be achieved ^-6 Or 12 log reduction sterilization processes of the bacillus subtilis var Aspergillus niger. The sterility assurance level is related to the probability that the sterilization unit will remain non-sterile after undergoing a sterilization process.

"wicking" refers to any suitable material through which an organic compound can migrate by capillary action. The wicking material may include paper strips, nonwoven polymeric fabrics, and inorganic fiber compositions. Preferred wicking materials are Whatman No. 1 filter paper, whatman No. 114 filter paper, PET fabric nonwoven, supported microcrystalline cellulose (TLC plate), supported alumina and supported silica gel.

"sufficient environmental conditions" refers to environmental conditions within the sterilization chamber that correspond to a sufficient sterilization process.

"conductive trace" refers to a conductive element that forms part of an electrical circuit. Or may be a wire.

The phrase "comprising (including) at least one of … …" of a subsequent list is intended to encompass (including) any one of the items in the list as well as any combination of two or more items in the list. The phrase "… …" of a subsequent list refers to any one item 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 "admittance". Depending on the context, the impedance or admittance may be used as a change in the impedance of a material as well as 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.

Unless otherwise indicated, all numerical ranges include the endpoints and non-integer values between the endpoints (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

These and other aspects of the disclosure will be apparent from the following detailed description. The above summary, however, should not be construed in any way as limiting the claimed subject matter, which is defined solely by the appended claims as may be amended during prosecution.

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 drawings, in which:

fig. 1 illustrates a sterilization system that may be used in conjunction with the sensors of the present disclosure.

Fig. 2 illustrates a sensor device according to some embodiments of the present disclosure.

Fig. 3 illustrates use of a sensor device in a sterilization system according to some embodiments of the present disclosure.

Fig. 4 illustrates use of a sensor device in a sterilization system according to some embodiments of the present disclosure.

Fig. 5 illustrates a sterilization indicator system according to one embodiment.

Fig. 6A illustrates a sterilization indicator sensor according to one embodiment.

Fig. 6B illustrates an alternative sterilization indicator sensor, according to one embodiment.

Fig. 7 illustrates a sterilization indicator sensor at different viewing angles.

Fig. 8 illustrates a method according to one embodiment.

While the above-identified drawings, which may not be to scale, illustrate various embodiments of the 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 limitation. 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 the disclosure.

Detailed Description

Chemical indicators are widely used for sterilization monitoring to ensure that the sterilization process has been properly completed. Failed or inadequate sterilization cycles can pose a significant risk to the patient due to potential cross-contamination from reprocessing surgical instruments.

Conventional chemical indicators are based on colorimetric changes in the presence of a sterilant and operating conditions of the sterilant (such as sterilization temperature and sterilization time). For example, the color of the vapor indicator may change from light yellow to black. Another type of chemical indicator (such as a Bowie-Michael test pack) is designed to detect sterilizer leaks or underexhausts.

In current practice of visually evaluating chemical indicators, a user needs to visually judge the color development to determine whether the chemical indicator has undergone a sufficient sterilization process. However, color development may be relatively subjective. Therefore, a better system is highly desirable.

Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of use, construction and arrangement of components set forth in the following description. The disclosure is susceptible to other embodiments and to operation or practice in various ways, which will become apparent to one of ordinary skill in the art upon reading. In addition, it is to be 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 to be 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 characteristics, 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 list of embodiments may 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 is responsive to environmental conditions (including the presence of sterilant such as steam) during sterilization. In general, the sensor devices of the present disclosure enable electronic reporting of information about each sterilization cycle (e.g., pass/fail information, accept/reject information) to avoid subjective judgments (e.g., color changes perceived by the human eye) that may lead to errors. Furthermore, the system and apparatus of the present disclosure enable the digitization of sterilization results, which in turn would save technicians from manual recording and physical storage.

Fig. 1 illustrates a sterilization system 100 in which the sensor devices of the present disclosure may be employed. As shown in fig. 1, sterilization system 100 may include a chamber 110 into which a sterilant flow 120 may be directed. 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 may be employed for purposes of this disclosure. For example, the sterilization system 100 may be based on steam or hydrogen peroxide (e.g., vaporized hydrogen peroxide), and each type may have different sterilization process conditions. Examples of sterilizer systems using hydrogen peroxide as a sterilant are commercially available from Shi Dirui (Steris) (door holder, ohio, usa) or Tuttnauer (israel). Examples of sterilizers that use steam as the sterilant are commercially available from Shi Dirui (door holder, ohio, usa) or queueing (geting) (goldburg, sweden).

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

In some embodiments, the present disclosure relates to a sensor device configured to determine whether a sterilization process within a sterilization system is performed according to a predetermined guideline, or whether a sufficient sterilization process is achieved. The adequate sterilization process may vary based on the sterilant used, the manufacturer of the sterilizer, or the article to be sterilized. For example, disease control center health care facility disinfection and sterilization guidelines (Guideline for Disinfection and Sterilization in Healthcare Facilities, center for Disease Control) (2008) (which is incorporated herein by reference in its entirety) provide minimum cycle times for sterilization of various product types and sterilants.

Referring to fig. 2, a sensor device 130 is depicted in accordance with some embodiments of the present disclosure. Sensor device 130 may include a first electrode 135, a second electrode 140 (sometimes collectively referred to as an electrode pair), and a sterilant response bridge 145 that may facilitate electrical communication between first electrode 135 and second electrode 140. In some implementations, each of the first electrode 135 and the second electrode 140 can be in electrical communication or electrically coupled (via physical contact or via an intermediate such as a conductive member (e.g., a conductive wire)) via the sterilant response bridge 145. As shown in fig. 2, in some embodiments, the ends of each of the first electrode 135 and the second electrode 140 may be in physical contact with the sterilant response bridge 145. In some embodiments, without sterilant response bridge 145, electrode pairs 135, 140 may not be in electrical communication (i.e., the electrodes are not in physical contact or are spaced apart at least a distance such that there is no electrical communication without an intervening conductive member).

In some embodiments, the first electrode 135 and the second electrode 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 conductive polymer.

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

In some embodiments, still referring to fig. 2, bridge 145 may include a conductive polymer, a plurality of one or more types of metals or metal-containing particles, and optionally a polymeric binder. For example, the conductive polymer and metal particles may be dispersed in a polymeric binder and deposited on the electrode pairs. As another example, the conductive polymer may be disposed in a layer deposited over the electrode pairs, and the metal particles may be present in a sterilant soluble (e.g., vapor soluble) layer coated over the conductive polymer layer such that the metal particles diffuse into the conductive polymer after exposure to the sterilant.

In general, the conductive polymer material may be any polymer material that is transitionable between a first impedance state and a second impedance state. In some embodiments, suitable conductive polymers may be those that are capable of transitioning from a first impedance state to a second impedance state in response to a change in an environmental condition (e.g., transitioning from a first state to a second state upon contact with a sterilant, or transitioning from a first state to a second state upon achieving a sufficient sterilization process within 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 undoped (e.g., by including and activating an alkaline material) non-conductive state (or at least a conductivity lower than that of the conductive state). In some embodiments, a low impedance state refers to having an admittance sufficient to bridge open, e.g., having an admittance of at least 2 siemens.

In some embodiments, the conductive polymer material of bridge 145 can have the following repeating units: aniline, acetylene, pyrrole, phenylene, phenylenevinylene, phenylsulfide, fluorene, pyrene, azulene, naphthalene, carbazole, indole, thiophene, ethylenedioxythiophene, or combinations thereof. The conductive polymer material may be doped or undoped with various dopants such as: dinonylnaphthalene sulfonic acid (DNNSA), dodecylbenzene sulfonic acid (DBSA), arsenic pentafluoride, triiodide, camphorsulfonate, methanesulfonic acid, halogen or polyhalogen ions, methanol, bisulfate, hydrochloric acid, tetrafluoroborate, sodium sulfite, or combinations thereof.

In some embodiments, the conductive polymer material comprises or consists essentially of Polyaniline (PANI). In some embodiments, the conductive PANI is in the form of an electrolyte, polyelectrolyte, or PANI salt, which can be readily achieved by acid doping PANI. PANI can be in one of three oxidation states (reduced polyaniline, emeraldine (salt or base form) and all (nigrosine)). Emeraldine may be non-conductive in the base form and conductive in the polyelectrolyte form or salt form. Emeraldine salts can be converted to non-conductive colorless emeraldine salts or full (nigrosine) by a redox reaction. The conductive polymer may be converted to a non-conductive polymer by a dedoping reaction. In some embodiments, the conductive polymeric materials of the present disclosure may initially exist in the emeraldine salt form and may be converted to the colorless emeraldine salt form upon exposure to a sterilant.

In some embodiments, suitable metals or metal-containing particles may include conductive metal particles. Additionally or alternatively, in some embodiments, the metal particles may be characterized as redox particles (i.e., particles that promote a chemical reaction in the bridge 145 in the presence of a sterilant (e.g., steam) that involves one molecule losing one or more electrons (oxidation-metal redox particles) and simultaneously gaining electrons (reduction-conductive polymer) through another molecule. In some embodiments, suitable redox particles may include aluminum, tin, bismuth, nickel, lead, indium, chromium, gallium, iron, vanadium, cadmium, titanium, zirconium, nob, tungsten, thallium, germanium, or lanthanoids. In some embodiments, the metal particles may include tin. In some embodiments, suitable metal particles may include a metal alloy, such as a silver-tin alloy, a gold-tin alloy, or an indium-tin alloy.

In some embodiments, useful metal redox particles may be those that 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 the PANI electrolyte or polyelectrolyte (protonated form) to its colorless emeraldine salt form. One example of such a mechanism is as follows:

in some embodiments, suitable metals or metal-containing particles may include conductive metal particles, non-conductive metal oxides, metal complexes, or combinations thereof, which may be characterized as catalyst particles (i.e., particles that catalyze chemical reactions in the bridge 145 in the presence of a sterilant (e.g., hydrogen peroxide) that involves the formation of byproducts that cause a localized pH increase in the vicinity of the conductive polymer). In some embodiments, suitable catalytic 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, vanadyl acetylacetonate, 1:1 copper (II) -, manganese (II) -, cobalt (II) -or nickel (II) -hexamine complexes.

In some embodiments, useful metal catalyst particles may include those capable of catalyzing a reaction with a sterilant (e.g., hydrogen peroxide) to produce hydroxide anions and water as byproducts. The presence of hydroxide anions in turn can raise the local pH near the conductive polymer, which can lead to capturing protons to neutralize the PANI electrolyte or polyelectrolyte (protonated form) to its neutral or less protonated emeraldine form. Examples of such a set of reactions (using hydrogen peroxide as a sterilant) are as follows:

in some embodiments, useful metals or metal-containing particles may include those metals or metal-containing particles that may be activated by a sterilant (e.g., steam or hydrogen peroxide) to produce free electrons, hydrides, or hydrogen that are capable of reducing the conductive polymer from a first conductive state to a second conductive state (e.g., converting PANI from an Emeraldine Salt (ES) state to a colorless emeraldine salt (LS) state). Examples of such a set of reactions are shown below (imbalance equation):

m may be a monovalent metal or a polyvalent metal

In any of the above embodiments, the metal or metal-containing particles may be nanoparticles. In this regard, the metal particles may have an average size (according to the average longest dimension) of between 0.01 microns and 0.1 microns or between 0.001 microns and 1 micron; or no greater than 5 microns.

In embodiments including a polymeric binder, the polymeric binder may include any suitable binder, such as polyurethane, polyvinyl butyral, polyacrylate, polyvinyl acetate, polystyrene acrylate, polyurea, polyimide, amide, epoxy, glycidyl-Si-Zr containing sol gel, polyester, phenoxy resin, polysulfide, or mixtures thereof.

In some embodiments, the conductive polymer may be present in the bridge 145 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 composite material forming the bridge 145.

In some embodiments, the metal particles may be present in the bridge 145 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 composite material forming the bridge 145. In general, the amount of metal particles present in the bridge may be the amount necessary to convert the conductive polymer from the first impedance state to the second impedance state acid state upon exposure to the sterilant.

In some embodiments, the polymeric binder may be present in the 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 composite material forming the bridge 145.

In some embodiments, bridge 145 may exhibit a change in color in addition to a change in impedance state. For example, in embodiments where bridge 145 includes PANI, bridge 145 may begin with 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 way, a visual determination of the adequacy of the sterilization cycle may be performed.

In some embodiments, the sensor device 130 may be a stand-alone device that may be placed into 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 tortuous path (such as a porous matrix or lumen channel), a Bowie-Dick test pack, etc.) that may include a housing and one or more internal components or materials configured to facilitate ensuring that adequate sterilization conditions exist during a sterilization cycle.

Referring now to fig. 3, the use of a sensor device 130 in a sterilization system 100 is shown, according to some embodiments of the present disclosure. As shown, the sensor device 130 may be disposed within the chamber 110 of the sterilization system 100. In some embodiments, the sensor device 130 may be disposed within the chamber 110 such that it may interact with components of the sterilant flow 120 upon entering the chamber 110. In some implementations, a reader device 160 may also be provided.

In some embodiments, reader device 160 may be configured to receive signals from sensor device 130 and convert the received signals into a determination (e.g., pass/fail determination) related to the adequacy of the sterilization cycle. For example, the reader device 160 may be configured to interrogate the sensor device 130 such that the reader device 160 measures an impedance across the electrode pair (e.g., a single reading over time or a continuous or semi-continuous reading) that may correspond to whether various environmental conditions are achieved during the sterilization process, or whether a sufficient sterilization process is achieved. In some embodiments, when exposed to a first environmental condition (e.g., an environmental condition), the reader device 160 (if interrogating the sensor device) will measure a first impedance value that indicates whether the conductive polymer of the bridge 145 is in a first impedance state or a second impedance state. As described above, a change in environmental conditions (or a second environmental condition) within the chamber 110 may change the impedance state of the conductive polymer and thus the impedance across the electrode pair measured by the reader device 160. In some embodiments, a first resistance can be measured across the first electrode and the second electrode when the conductive polymer is in the first impedance state, and a second resistance can be measured across the first electrode and the second electrode when the conductive polymer is in the second impedance state, and the first resistance is different from the second resistance.

In some embodiments, reader device 160 may be in electronic communication (or capable of electronic communication) with sensor device 130 (continuously or at any desired interval) (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 a pair of electrodes of sensor device 130)). In some embodiments, reader device 160 may be a device for measuring resistance (e.g., an electrical multimeter).

Referring now to fig. 4, the use of a sensor device 130 in a sterilization system 100 is shown, according to some embodiments of the present disclosure. As shown, the sensor device 130 may again be disposed within the chamber 110 of the sterilization system 100 such that it may interact with components of the sterilant flow 120 upon entering the chamber 110. In addition, one or more medical devices 165 to be sterilized may be provided with the chamber 110. For example, as shown, the sensor device 130 and the one or more medical devices 165 may be housed together in a package 170 (commonly referred to in the industry as a tray). It should be appreciated that each package 170 may house any number of medical devices 165 or any 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. A reader device 140 may also be provided, as in the embodiment shown.

In some embodiments, the present disclosure also relates to methods of using the sensor device 130 in the sterilization system 100. The method may begin with a user placing the sensor device 130 in the chamber 110. As previously described, the sensor device 130 may be placed in the chamber 110 alone or may be placed with one or more medical devices to be sterilized (and may be packaged with the medical devices in a tray or provided in a chamber 110 separate from the medical devices or medical device tray). After the sensor device is placed in the chamber, the chamber 110 may be isolated from the environment.

In some embodiments, a user may activate a sterilization process of the sterilizer, and the sensor device may be exposed to a sterilant and/or one or more environmental conditions during the sterilization process. For example, if the sterilant is steam, the sterilant may be at least 95% saturated steam/steam, and the sterilization process may include achieving a temperature of 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 within the chamber 110. As another example, if the sterilant is hydrogen peroxide, the sterilant may be in an atmosphere containing at least 30% hydrogen peroxide vapor and the sterilization process may be conducted at least 50 degrees celsius for at least 60 minutes. Various criteria may exist for each sterilant and may vary based on the manufacturer, the article to be sterilized, or a combination thereof.

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

In some embodiments, the method may further include continuously, intermittently, or at any desired time, reader device 160 receiving signals from sensor device 130 and converting such received signals into determinations (e.g., pass/fail determinations) related to the sufficiency of the sterilization cycle. As described above, the received signal may be related to the impedance measured across the electrode pair, which corresponds to various environmental conditions that have been achieved or not achieved during sterilization. For example, measured impedances above or below a predetermined value may be used to determine whether sufficient sterilization process conditions are achieved within the chamber 110.

In some alternative embodiments, aspects of the present disclosure relate to a sensor device having a sterilant responsive switch responsive to an environmental condition (including sterilant) during sterilization. The sterilant responsive switch may be electrically coupled to the conductive trace of the sensor device and may be mechanically activated or formed of a conductive polymer material.

Fig. 5 illustrates a sterilization indicator system 1100. The sterilization indicator system 1100 can include a sterilizer 1104.

The sterilizer 104 is configured to provide sterilant 1108 to the chamber 1112 during a sterilization process. Various examples of sterilizers 104 may exist and each sterilizer may differ in the type of sterilant 1108 provided. The sterilizer 1104 can be steam or hydrogen peroxide (e.g., vaporized hydrogen peroxide) based, and each type can have different sterilization process conditions. Examples of sterilizers that use hydrogen peroxide as a sterilant are commercially available from Shi Dirui (Steris) (Mentor, OH) or Tuttnauer (Israel), usa. Examples of sterilizers that use steam as a sterilant are commercially available from Shi Dirui (Steris) (Mentor, OH) of the united states.

The chamber 1112 may have one or more environmental conditions. In at least one embodiment, the environmental conditions may be related to conditions within the chamber 1112 and may include, but are not limited to, exposure time, sterilant, temperature, pressure, or combinations thereof. For example, a first environmental condition may be present in the pre-sterilization process and a second environmental condition may be present during the sterilization process. The sensor device 1102 may determine whether the second environmental condition corresponds to a sufficient sterilization process. The sufficient sterilization process may vary based on the sterilant used, the manufacturer of the sterilizer, and the article 1106 to be sterilized. For example, the disease control center health care facility disinfection and sterilization guidelines (Guideline for Disinfection and Sterilization in Healthcare Facilities, center for Disease Control) (2008) provide minimum cycle times for sterilization of the various article 1106 types and sterilants 108 in tables 1 and 7, which are incorporated herein by reference.

The sterilization indicator system 1100 includes a sensor device 1102 that is capable of collecting and providing data regarding environmental conditions within the chamber 1112 relative to a sterilization process. In addition, the sensor device 1102 can also be read by the sensing device 1110. The sensing device 1110 is an electronic device that can remotely read environmental conditions. In one example, the sensing device 1110 can read the sensor device 1102 in real-time through the walls of the chamber 1112 to determine the environmental conditions in the chamber 1112. For example, the wall may have a hole formed therein for reading the RFID tag directly through the steel wall. As another example, the sensing device 110 can read/interrogate the sensor device 1102 to determine the environmental condition of the chamber 112 when outside the wall of the chamber 1112 (e.g., when in the wrapped package 1114). In at least one embodiment, a sufficient sterilization process may alter the electrical impedance of the sensor device 1102 and be detected by the sensing device 1110.

The sensing device 1110 may read the sensor device 1102 using wireless communication or wired communication. For example, if wired, the sensor device 1102 may include a storage element to store environmental conditions captured by the sensor device 1102. In at least one embodiment, the sensor device 1102 may be affected by past environmental conditions and may be chemically or electrically modified. For example, the sensor arrangement 1102 may also include a sterilant responsive switch that directly or indirectly indicates an environmental condition from a sterilization process in the chamber 1112.

The sensor device 1102 may include any type of sterilant resistant integrated circuit or simple circuit breaker. The sensor device 1102 may include any suitable electrical connection to communicate with a sensing device 1110 that detects and measures any electrical signals generated. Such connections may include, but are not limited to, hardwired, physical electrical contacts (e.g., spring loaded or jacks), ethernet, bluetooth, 802.11, wireless Local Area Network (WLAN), wiFi, wiMAX, etc., or any other type of wired or wireless communication known in the art.

For example, the sensor device may be an RFID tag, a thermometer, a pressure sensor, a communication device, or a combination thereof. In at least one embodiment, the sensor device 1102 is an RFID tag and the sensing device 1110 is an RFID interrogator device. Exemplary RFID interrogator devices are UHF-based and commercially available from Zebra (Zebra) (lincolnsire, IL), alien Technology (Alien Technology) (San Jose, CA), or infrequency (Impinj) (Seattle, WA, washington). Other exemplary RFID interrogator devices are also commercially available from Jadak (Syracuse, NY), technical solutions limited (Technology Solutions Ltd) (United Kingdom), sampson or apple, or from RFID (Aurora, CO) in corrado, aor RFID (Ontario, canada), or SkyRFID (Ontario, canada).

The sensor device 102 may be paired with one or more components (such as a substrate and an environmental change receptor) to form a sterilization indicator sensor, as will be further described herein. In at least one embodiment, the environmental change receptor is different from the sterilant responsive switch. For example, the environmental change receptor may be configured to affect the admittance/impedance of the sterilant response switch.

In at least one embodiment, the article 1106 and the sensor device 1102 can be packaged in an enclosure 1114. The sensor device 1102 may be responsive to a sterilization process occurring in the chamber 1112. The sensor device 1102 can be read to determine that the sensing device 1110 is used without opening the package 1114, which helps ensure sterility of the article 1106 to the end user.

Fig. 6A shows a sterilization indicator sensor 200 for use in a sterilizer.

The sterilization indicator sensor 200 can include the sensor device 102 described herein. In at least one embodiment, the sensor device 102 may also include a monitoring loop 220. The monitoring loop 220 may include a sterilant responsive switch 208 that is electrically modifiable based on exposure to environmental conditions for a sterilization process, particularly a sufficient sterilization process. In at least one embodiment, the monitoring loop 220 is configured to electrically change based on exposure to a sufficient sterilization process. For example, the monitoring loop 220 may increase or decrease admittance/impedance based on exposure to a sufficient sterilization process.

Sterilant responsive switch 208 may be based on a conductive polymeric material or mechanical interaction with various components, such as environmental change receptor 204. In at least one embodiment, sterilant responsive switch 208 can comprise circuit 206, a conductive polymer having a first state and a second state, and a polymer binder (collectively 207). In at least one embodiment, sterilant responsive switch 208 may be binary. For example, sterilant response switch 208 may trigger from off to on indirectly based on the interaction of sterilant with environmental change receptor 204. In at least one implementation, the circuit 206 may be an integrated circuit.

Sterilant response switch 208 may also have a gradual response to environmental conditions. For example, the conductive polymer material may suffer from gradual electrical conductivity degradation based on interactions from the sterilant 108. Examples of sterilant responsive switches 208 are further described herein.

The conductive polymer material may be any substance having semiconducting properties or being capable of switching between a first state and a second state. In other words, the conductive polymer is capable of transitioning from being in the first state to being in the second state when in contact with the sterilant. In at least one embodiment, the first state may be a first impedance state having a first impedance and the second state may be a second impedance state having a second impedance, e.g., a solid substance having a conductivity between that of an insulator and that of a metal. In at least one embodiment, the impedance state may be related to the impedance and admittance of the sensor device. The impedance state may be inversely related to the flow of the conductive polymer material and include the resistance of the conductive polymer material and the accumulation of inductive and capacitive reactance. In at least one implementation, the first state may be a non-conductive state and the second state may be a conductive state, and vice versa. The conductive state may be a doped conductive state and the non-conductive state may be a non-conductive reduced form or a non-conductive oxidized form of the conductive polymer. In at least one embodiment, the conductive polymer may be in the form of a conductive polymer electrolyte, such as a protonated form. In at least one embodiment, the sterilant responsive switch connects the circuit in a first state and disconnects the circuit in a second state.

The conductive polymer material may include an electroactive polymer that changes from a first impedance state to a second impedance state or from the second impedance state to the first impedance state based on interaction with the environmental change receptor 204, an environmental condition, a conductive trace, or a combination thereof. In at least one embodiment, the first impedance state may correspond to having a higher or lower impedance relative to the second impedance state, depending on the mechanism. For example, polyaniline may switch from non-conductive to conductive, or vice versa. In at least one embodiment, the first impedance state refers to having an admittance and an impedance sufficient to bridge an open circuit, e.g., having an admittance of at least 2 siemens. The electroactive polymer may be a semi-flexible rod polymer. In at least one embodiment, the electroactive polymer may have the following repeat units: aniline, acetylene, pyrrole, phenylene, phenylenevinylene, phenylsulfide, fluorene, pyrene, azulene, naphthalene, carbazole, indole, thiophene, ethylenedioxythiophene, or combinations thereof. The electroactive polymer may be doped or undoped with various dopants such as: dinonylnaphthalene sulfonic acid (DNNSA), sodium, arsenic pentafluoride, tri-iodide, camphorsulfonate, methanesulfonic acid, halogen or polyhalogen ions, methanol, bisulfate, hydrochloric acid, tetrafluoroborate, sodium sulfite, or combinations thereof. Preferably, the conductive polymer material is Polyaniline (PANI), which may be in one of three oxidation states (reduced polyaniline, emeraldine (salt or base form), and full (nigrosine)). Emeraldine may be non-conductive in the base form and conductive in the salt form. In addition, when sterilant responsive switch 208 is contacted with steam or hydrogen peroxide, the emeraldine salt may be converted to a non-conductive colorless emeraldine salt or full (nigrosine) by a reduction reaction. When sterilant responsive switch 208 is contacted with steam or hydrogen peroxide, the conductive polymer can be converted to a non-conductive polymer by a dedoping reaction.

The polymeric binder may comprise any suitable binder, such as polyurethane, polyvinyl butyral, polyacrylate, polyvinyl acetate, polystyrene acrylate, polyurea, polyimide, amide, epoxy, glycidyl-Si-Zr containing sol gel, polyester, phenoxy resin, polysulfide, or mixtures thereof. In the case of a polymeric binder, the reduced non-conductive PANI may remain non-conductive for longer periods of time in certain structures (such as aluminum electrode pairs) without recovering (at least one year) or without recovering certain thresholds of certain metal particles (such as tin nanoparticles) above 2% w/w in the formulation. Surprisingly, the conductive polymer material can be changed from a first state to a second state without a binder, but the second state without a binder is reversible. For example, PANI may be reduced by steam sterilization, but the redox state of PANI without binder is reversible, i.e. non-conductive PANI may be rapidly reversed in air back to conductive PANI form. In addition, conductive polymers (e.g., PANI) can adhere to metal surfaces, but reduced non-conductive PANI can easily peel (flake) off the metal surface once it has been subjected to a sterilization process. In addition, when a polymeric binder is used, the conductivity of PANI in the solid film can be significantly improved without the need for alcohol washing. Thus, alcohol washing is optional when a binder is present, and the user can save cost and time without an additional alcohol washing step.

In addition, the sensing device 1110 can be configured to interrogate the sensor device 1102 such that the sensor device 1102 provides a plurality of impedance states over time that can correspond to various environmental conditions during sterilization. For example, when exposed to a first environmental condition, sensor device 1102 may transmit a first impedance state based on the interaction (directly or indirectly) of the sterilant responsive switch with the first environmental condition. The environmental conditions may change the measured capacitance of sterilant responsive switch 208. When exposed to a second environmental condition, sensor device 1102 may transmit a second impedance state based on the interaction of the sterilant responsive switch with the second environmental condition (directly or indirectly), and so on to a third impedance state and a fourth impedance state. In at least one embodiment, the sensing device 1110 can determine an environmental condition based on the impedance state and provide a gradual view of the environmental condition over time (as opposed to a binary pass/fail that may be present).

The sensor device 1102 may include a first electrode 214 having a first end 222 and a second end 224 and a second electrode 216 having a first end 226 and a second end 228. A first end of both electrode 214 and electrode 216 is electrically coupled to circuit 206. In at least one embodiment, the second ends of the electrodes 214 and 216 are not integrally attached using the same material as the electrode 214 or the electrode 216. In at least one embodiment, the second ends of electrode 214 and electrode 216 may each be connected by sterilant responsive switch 208.

In at least one embodiment, the distance 210 between the electrode 214 and the electrode 216 is measured along the sterilant response switch 208. The distance 210 may be sufficient to sense a change in electrical admittance/impedance without causing an electrical short or interference between the electrodes 214 and 216. For example, if distance 210 is zero, electrode 214 and electrode 216 will be electrically coupled and monitoring loop 220 will not sense an environmental condition, regardless of changes in sterilant response switch 208.

The electrode may comprise a metal, metal particles, carbon black, graphene, conductive polymer, carbon nanotubes, or a combination thereof. In at least one embodiment, the oxidation potential of the metal is greater than the reduction potential of the conductive polymer. Examples of suitable metals may include aluminum, iron, zinc, tungsten, molybdenum, tin, nickel, copper, or alloys thereof. For example, it has surprisingly been found that the use of aluminum reacts directly with PANI and converts emeraldine salts to reduced polyaniline salts. Thus, the monitoring loop 220 may change from a first impedance state to a second impedance state based on a redox reaction of the conductive polymer material and the metal under ambient conditions corresponding to a sufficient sterilization process (e.g., of steam).

In at least one embodiment, sterilant responsive switch 208 comprises electrically conductive particles 209. In some embodiments, the conductive particles 209 may be coated on the first electrode and the second electrode, as shown in fig. 6A. In at least one embodiment, the conductive particles may include metal-containing particles, and the metal of the metal-containing particles is selected from copper, cobalt, manganese, zinc, iron, silver, tin, lead, gallium, platinum, osmium, iridium, palladium, ruthenium, rhodium, gold, or alloys thereof. In at least one embodiment, the conductive particles comprise activated carbon, C60, carbon nanotubes, graphite, metal oxides, and conductive organic polymer particles comprising insoluble conductive polymers such as polyaniline, polypyrrole, and polythiophene, or a combination of conductive inorganic particles and organic conductive particles.

In at least one embodiment, the sterilization indicator sensor 200 can include only the sensor device 1102. The sterilization indicator sensor 200 can also optionally include a first substrate 202 and/or an environmental change receptor 204.

In at least one embodiment, a portion of sterilant responsive switch 208 can contact first substrate 202. The first substrate 202 may be wicking or non-wicking. If non-wicking, the first substrate 202 may be any metal layer such as aluminum foil, or a polymer layer such as a polyethylene, polyurethane, or polyester layer. In at least one embodiment, the first substrate 202 may provide structural support to the sensor device 102. The first substrate 202 may also provide support for an environmental change receptor 204.

If wicking, the first substrate 202 may be any suitable material through which organic compounds may migrate by capillary action. The preferred wicking first substrate 202 is a paper strip. Other such wicking materials may be used, such as nonwoven polymeric fabrics and inorganic fiber compositions. The size of the wicking first substrate 202 is not critical. However, its dimensions (thickness and width) will affect the wicking rate and determine the amount of organic compound needed to produce the proper scale length. Therefore, from an economical point of view, the wicking first substrate 202 should be as thin as possible. A suitable width of the first substrate 202 is about 3/16 inch to about 1/4 inch. Examples of wicking first substrate 202 are Waterman No.1 filter paper, waterman No.114 filter paper, supported microcrystalline cellulose (TLC plate), supported alumina, and supported silica gel. In some embodiments, the conductive particles 209 may be coated on the first substrate 202. In some embodiments, the first electrode and the second electrode may be printed on the conductive particle coating.

In at least one embodiment, the environmental change receptor 204 is disposed adjacent to the first substrate 202. For example, the environmental change receptor 204 may be positioned such that the environmental change receptor 204 flows onto the first substrate 202 and is wicked from the first substrate position to the second substrate position (which may correspond to a portion of the sterilant response switch 208) as indicated by the flow direction 218. In at least one embodiment, the environmental change receptor 204 can also be disposed directly on the first substrate 202 at the first substrate location. In at least one embodiment, the environmental change receptor 204 is disposed proximate or adjacent to the sterilant response switch 208. In at least one embodiment, the environmental change receptor 204 is solid and may be in the form of a tablet, and is disposed external to the first substrate 202. In at least one embodiment, the environmental change receptor 204 can be embedded within or layered on the first substrate 202.

The environmental change receptor 204 may include one or more environmental responsive or sensitive materials selected according to sensing needs. The environmentally responsive material may be selected based on its solubility, boiling point, melting point, ability to absorb gas or liquid, softening point, or flow characteristics such that it changes characteristics (evaporates or redistributes over sensor strips) in response to particular environmental conditions. In some cases, the environmental change receptor 204 may include more than one component, where each component may include similar or different environmentally responsive materials and may be disposed at different locations. In at least one embodiment, the environmental change receptor 204 may be selected based on the ability to change the admittance/impedance of the sterilant responsive switch. The environmental change receptor 204 may be acidic or basic to affect the first impedance state of the conductive polymer material. For example, if the environmental change receptor 204 is alkaline, the base may react with the emeraldine salt to form an emeraldine base and change from a first impedance state to a second impedance state.

The environmental change receptor 204 may include a type of meltable or flowable material, such as a crystalline or semi-crystalline material (e.g., tetra-n-butyl ammonium bromide (TBAB), a thermoplastic, a polymer, a wax, an organic compound such as salicylamide, a polyethylene-acrylic acid copolymer, sucrose, or the like.

Some environmental change acceptors can respond to steam sterilants at ambient conditions to perform a sufficient sterilization process. In at least one embodiment, the environmental change receptor 204 can include an organic base that has a melting point greater than 100 ℃ and is miscible with salicylamide. For example, the organic base may be N, N-lutidine, amantadine, or a combination thereof.

Some environmental change acceptors may also respond to steam or hydrogen peroxide sterilants during the full sterilization process. Such environmental change receptors can include various pigments and inks, such as blue inks and pink pigments. In addition, the environmental change receptor may include an organic ester that is solid at room temperature. In at least one embodiment, sterilant 108 can interact with environmental change receptor 204, sterilant responsive switch 208, or both to produce a change that will affect sensor device 102.

The sensor device 200 may include an antenna 212 capable of receiving energy from and transmitting data to the sensing device 1110. The antenna 212 may be various shapes optimized for transmission to the sensing device 110. One example of an antenna 212 design is commercially available under the model name BELT from smartac (Netherlands).

In at least one embodiment, the antenna 212 may be formed such that it is not affected by the sterilization process. For example, antenna 212 may have no interruption within the antenna loop (but sensor device 1102 may have an interruption within monitoring loop 220). The antenna 212 may be electrically coupled to the integrated circuit 206 and form an antenna loop. The integrated circuit 206 may draw energy from the sensing device 110 to transmit the antenna 212 impedance. Various integrated circuit 206 devices may be designed for RFID applications, such as passive, semi-active, and active RFID applications, and are commercially available from the en zhi pu semiconductor (NXP Semiconductors) (Netherlands), inflight (Impinj) (Seattle, WA) or peace (Axzon) (Austin TX) of washington. Examples of integrated circuit 206 are available under the trade name Magnus from security (Austin, TX) or UCODE G2iM or g2il+ from enzhima semiconductors, which may include UHF RFID transponder capability and tag tamper alarms capable of measuring the status of monitoring loop 220.

In at least one embodiment, the sensor device 200 may include a second integrated circuit that is responsive to a different frequency than the first integrated circuit. The second integrated circuit may be electrically coupled to antenna 212 or a second antenna. The second integrated circuit may also be electrically coupled to the monitoring loop.

Fig. 6B illustrates a sterilization indicator sensor 200 that is similar to the sterilization indicator sensor 200 of fig. 6A, except that the circuit 206 is read by direct physical contact with a sensing device 1110 for impedance or resistance measurement. The direct physical contact may be a hardwired electrical connection 250 between the electrode and circuitry for detecting and measuring the electrical signal generated by the electron transfer.

Fig. 7 illustrates a sterilization indicator sensor 1300 at a different perspective. Conductive trace 1314 and conductive trace 1316 are shown to contact polymer gate material 1306. Upon exposure to a sterilant, the polymer gate material 1306 may change the admittance/impedance sensed by the RFID interrogator device.

In at least one embodiment, the sterilization indicator sensor 1300 can be present in a card stack, which can generally be paper or formed from a first substrate. The sterilization indicator sensor 1300 can be similar in structure to the chemical indicator described in U.S. patent No. 9,170,245, which is incorporated herein by reference. In at least one embodiment, the card stack can have a sterilization indicator sensor 1300 positioned in the middle of the card stack.

In at least one embodiment, the sterilization indicator sensor 1300 can form a central region 1320 and a peripheral region 1322. Peripheral region 1322 may surround central region 1320. In at least one embodiment, the central region 1320 may only partially contact the sterilant when disposed in the card stack. The central region 1320 may be the result of an air pocket formed by a card stack having the sterilization indicator sensor 1300. In at least one embodiment, the central region can reflect the shape of the sterilization indicator sensor 1300. For example, the central region 1320 may be rectangular (such as diamond) or oval in shape. In one example, the sterilization indicator sensor 1300 has an area no greater than 25 square inches and a central region 1320 no greater than 1 square inch. Thus, the ratio of the total area to the central area may be no greater than 25:1.

In at least one embodiment, the air bag may represent a last sterilized test path. In at least one embodiment, the polymer gate material 1306 is positioned in the geometric center and/or central region of the first substrate 1302 such that the polymer gate material 1306 detects whether sufficient environmental conditions are present in the central region. For example, when packaged in a card stack, sterilant may interact with the peripheral region 1322, but may require time to interact with the central region 1322. As shown, the polymer gate material 1306 contacts the ionic salt 1304.

In at least one embodiment, the stack may be fully wrapped in a sheet of material to form a wrapped package. For example, the sheet of material may be a nonwoven, which may be a sterilant permeable medical wrap commercially available as a sterilization wrap.

Fig. 8 illustrates a method 1500 of using a sensor device.

The method 1500 may begin at block 1502. In block 1502, a user may place a sensor device in a chamber of a sterilizer. In at least one embodiment, the user may place the sensor device and the article to be sterilized in the chamber. The user may also package the sensor device and the article together in a wrapped package such that the sensor device is not visible when the package is wrapped. The sensor device is further described herein and includes a sterilant responsive switch. In at least one embodiment, the user may place a sensor device, which may be part of a sterilization indicator sensor, which may be placed in the chamber. After the sensor device is placed in the chamber, the chamber may then be isolated from the environment.

In block 1504, a user may activate a sterilization process of the sterilizer, and the sensor device may be exposed to a sterilant and/or one or more environmental conditions during the sterilization process. For example, if the sterilant is steam, the sterilant is at least 95% saturated steam/water vapor and the sterilization process is 2 minutes at 134 ℃ or 10 minutes at 121 ℃. As another example, if the sterilant is hydrogen peroxide, the ambient conditions are an atmosphere containing 31% hydrogen peroxide vapor and the sterilization process is 60 minutes at 50 ℃. Various criteria may exist for each sterilant and may vary based on the manufacturer, the article to be sterilized, or a combination thereof. In at least one embodiment, the environmental conditions include the presence of a sterilant.

In block 1506, the sterilant response switch of the sensor device or sterilization indicator sensor may be reacted (physically or chemically) with the sterilant or with an environmental condition (which may include sterilant). In at least one embodiment, the sterilant responsive switch can also interact with the substrate or environmental change receptor to modify the admittance/impedance of the sterilant responsive switch. For example, an environmental condition, an environmental change receptor, or a combination thereof may cause a sterilant responsive switch to change from a first state to a second state (e.g., from a first impedance state to a second impedance state), or vice versa. In at least one embodiment, the conductive particles can react with the sterilant and/or the conductive polymer to alter the impedance of the conductive polymer upon exposure to suitable environmental conditions including steam sterilants or hydrogen peroxide sterilants. In at least one embodiment, the conductive particles may first react with the sterilant and then react with the conductive polymer to alter the impedance of the conductive polymer upon exposure to suitable environmental conditions including steam sterilant or hydrogen peroxide sterilant. In at least one embodiment, it can trigger a redox reaction in the sterilant responsive substrate to alter the impedance of the conductive polymer when exposed to suitable environmental conditions including a steam sterilant or a hydrogen peroxide sterilant.

In blocks 1508 through 1514, the sensing device may be configured to be capable of reading the sensor device to determine whether the first impedance state exists.

In at least one embodiment, the sensing device is configured to read the sensor device through the wrapped package. The sensing device may also be configured to read the sensor device when the chamber is sealed (i.e., sealed by the housing of the sterilizer). The sensing device may use on-board memory to read the sensor device later. In at least one embodiment, the sensing device may be an RFID interrogator device. In block 1508, the sensing device may be configured to transmit a first radio signal to the sensing device. The first radio signal may be of various frequencies, but is preferably UHF (300 MHz to 3000 MHz).

In block 1512 or block 1514, the first radio signal may affect the sensor device, and the sensor device may transmit the second radio signal or the third radio signal. For example, in decision block 1510, if the sterilant response switch is exposed to a sterilization process (e.g., a sufficient sterilization process), then in block 1512 the sensor device may output a second radio signal. If the sensor device is not exposed to a sufficient sterilization process, then in block 1514, the sensor device may output a third radio signal. In at least one embodiment, the output may be intrinsic and does not require any computational resources of the sensor device. In at least one embodiment, the second radio signal may indicate whether the sterilant response switch has degraded (e.g., the sterilant causes direct or indirect degradation of the sterilant response switch). In at least one embodiment, the second radio signal may indicate whether the sterilant responsive switch completes a circuit of a monitoring loop of the sensor device. The third radio signal may indicate that the sterilant response switch is not degraded or has minimal degradation.

The presence of the second radio signal or the third radio signal may indicate to the sensing device whether the sensor device is exposed to environmental conditions from a sufficient sterilization process. The sensing device may also communicate whether a sufficient sterilization process is achieved and thus perform a subsequent action.

Examples

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, as well as in the remainder of the specification, are by weight unless otherwise specified. The materials used in the examples and their sources are provided in table 1. Unless otherwise indicated, solvents and other reagents used were obtained from milbeg sigma company, st.Louis, misu (MilliporeSigma, st.Louis, MO).

TABLE 1

Material

Experiment 1

4 grams of the parent solution prepared according to the formulations provided in table 2 were aliquoted into 4 different vials. 160mg of silver nanopowder was added to the first vial. To a second vial was added 80mg of tin nanopowder. To the third vial was added 80mg of copper nanopowder. The fourth vial served as a control. Each vial was then sonicated for 10 minutes. A fourth vial without any metal powder added was used as a control. Then, by mixing equal parts of the nanopowder solution and the parent solution (without metal), each nanopowder solution is diluted sequentially in different vials to produce 4% to 0.25% (weight percent based on the parent formulation) PANI/metal solution. All solutions were thoroughly mixed with a small stirring bar for 1 hour.

Samples of each of these solutions were then coated on a 3 mil thick poly (ethylene terephthalate) (PET) film using a #24 Meyer rod and left in an oven at 145 ℃ for 10 minutes. The coated PET samples were then cut into approximately 1 inch wide strips and attached to a white nylon film sheet. Color was measured with a alice densitometer. The resistance was measured using a multimeter with the two pins 1 inch apart. After measuring the color and resistance, one sheet was subjected to a steam sterilization cycle (sterilization) at 134 ℃ for 4 minutes. The other sheet was sterilized using a hydrogen peroxide sterilizer (Sterrad 100S). After each piece was processed, the samples on each piece were measured again using a alice densitometer and a multimeter.

Tables 3 and 4 show the color change and resistance change before and after sterilization using steam and hydrogen peroxide, respectively. As can be seen from table 3, the Sn nanopowder samples showed a significant resistance change and a significant increase in a-value (change in color from green to pale yellow) after steam sterilization. This suggests that tin nanopowders can effectively convert conductive PANI into non-conductive form. Samples made using silver nanopowder and copper nanopowder did not cause significant resistance change when the coated sensors were exposed to the same steam sterilization cycle. As can be seen from table 4, all copper solutions from 2% to 0.25% and relatively high concentrations of silver nanopowder (4%) effectively changed the coating resistance when the sensor was exposed to a hydrogen peroxide based sterilization cycle.

It should be noted that the b-value also varies significantly (from green to dark emerald). It is assumed that both copper and silver can act as catalysts to degrade hydrogen peroxide to produce hydroxide ions that neutralize the acid-doped PANI to convert it from a conductive form to a non-conductive form (a de-doping process).

TABLE 2

Parent formulation for preparing metal nano-powder doping solution

Assembly	(weight basis)
		50% PANI in toluene	14.92
MIBK	41.98
		Xylene (P)	29.57
Desmodur 3390	8.48
		CAPA 3031	4.75
Zoldine MS-plus	0.3

TABLE 3 Table 3

Color and resistance of coated film samples

Before and after steam sterilization at 134 ℃ for 4 minutes

TABLE 4 Table 4

Color and resistance of coated film samples before and after hydrogen peroxide sterilization

Experiment 2

PANI/PU coating solutions containing 1% and 0.5% copper nanopowder and tin nanopowder, respectively, were prepared using the procedure of example 1. In a single vial, the solution containing 1% tin and the solution containing 1% copper coating solution were mixed in equal amounts and thoroughly mixed. The resulting samples were coated on 3 mil PET and tested as described in example 1. The samples were sterilized using steam (AMSCO Lab110, 134 ℃ for 3.5 minutes) and hydrogen peroxide (Sterrad 100S). Tables 5 and 6 show the resistance and color measurement changes. The results indicate that Sn is particularly reactive to steam sterilization, while copper reacts with hydrogen peroxide. Unexpectedly, the mixed solution containing both tin and copper counteracts the tin reaction to steam sterilization without affecting the copper performance in hydrogen peroxide sterilization.

TABLE 5

Color and resistance change after steam sterilization at 134 ℃ for 3.5 minutes

TABLE 6

Color and resistance change in hydrogen peroxide sterilization cycles

Experiment 3

PANI/PU coating solutions containing 1% and 0.5% silver, copper and tin nanopowder solutions, respectively, were prepared using the procedure of example 1. In a separate vial, the 1% tin containing solution and the 1% silver containing solution were added in equal amounts and mixed thoroughly. In another vial, the 1% tin containing solution and the 1% copper containing solution were mixed in equal amounts and thoroughly mixed. Each of these solutions was coated on 3 mil PET and tested as described in example 1. Sample strips prepared by coating each of these solutions were sterilized using steam (AMSCO Lab 110, 3.5 minutes at 134 ℃) and hydrogen peroxide (Sterrad 100S). Tables 7 and 8 show the resistance and color measurements before and after sterilization. The data show that the samples containing Sn nanopowder still reacted to steam sterilization, while the samples containing silver nanopowder and copper nanopowder reacted to hydrogen peroxide, as shown in the previous examples. One difference from experiment 2 is that unlike copper, silver nanopowder does not affect the performance of tin in steam sterilization.

TABLE 7

Color and resistance before and after steam sterilization at 134 ℃ for 3.5 minutes

TABLE 8

Color and resistance before and after hydrogen peroxide sterilization cycle

Example 4

A 100nm thick layer of aluminum was vapor deposited using a mask onto a 3 mil thick PET film patterned with two 5mm x 5mm pads (with 1mm gap, with two extending legs). The pads were then bar coated with the parent formulation shown in table 2 mixed with 0.5% copper nanopowder prepared as described above. The coating solution was applied using a #24 meyer rod and then heated in an oven at 145 ℃ for 10 minutes. The resistance of six prepared coated samples was measured using a multimeter, with two pins in direct contact with two electrical measurement feet, before and after subjecting the samples to a hydrogen peroxide sterilization cycle. Table 9 shows the resistance change and associated color change for each sample. The data show that the resistance of the coating changes significantly after exposure to hydrogen peroxide on the metal electrode.

TABLE 9

Resistance before and after hydrogen peroxide sterilization cycle

Example 5

Tamper evident RFID tags (modified with two 5mm x 5mm aluminum pads extending from the IC, as shown in fig. 2) were each coated with PANI precursor solutions mixed with 0.5% tin nanopowder and 0.5% copper nanopowder. The tag was read as "open" using a ThingMagic Pro RFID reader prior to coating. After the PANI solution containing tin or copper nanopowders was coated and heated as described in example 1, the tag was read as a "short" because the conductive polymer coating bridged the gap between the two metal pads on the RFID tag. The Sn/PANI coated RFID was then wrapped in a Bowie-Dick test pack (inside a stack of index cards) and sterilized at 134 ℃ for 3.5 minutes for a complete sterilization cycle. After processing the Bowie-Dick test packet, the "off" RFID is again read by the test packet, indicating that a steam-triggered chemical reaction has occurred on the RFID surface. Under the same conditions, control samples without polymer coating were always read as "off" before and after steam sterilization. copper/PANI coated RFID tags were placed on porous silicon pads and on the bottom of plastic sterilization trays, which were then closed. Prior to exposure to hydrogen peroxide, the RFID was read as a "short" due to the PANI/Cu coating. After the hydrogen peroxide sterilization is completed, the tray is removed from the sterilizer and the RFID tag "off" is again read through the tray, demonstrating the remote sensing capability of the RFID device to detect the hydrogen peroxide sterilization process without approaching the sensor. The control sample without the polymer coating showed a consistent "off" response from the RFID reader.

All references and publications cited herein are expressly incorporated by reference in their entirety into this disclosure. Exemplary embodiments of the present disclosure are discussed and reference is made to possible variations within the scope of the present disclosure. For example, features described in connection with one exemplary embodiment may be used in connection with other embodiments of the disclosure. These and other variations and modifications in the disclosure will be apparent to those skilled in the art without departing from the scope of the disclosure, and it should be understood that this disclosure is not limited to the illustrative embodiments set forth herein. Accordingly, the present disclosure is to be limited only by the claims provided below and the equivalents thereof.

Claims

1. A sensor device, the sensor device comprising:

a first electrode and a second electrode, each of the first electrode and the second electrode electrically coupled to a bridge;

the bridge includes:

a conductive polymer having a first impedance state and a second impedance state different from the first impedance state; and

metal or metal-containing particles.

2. The sensor device of claim 1, wherein the bridge is configured such that the conductive polymer changes from the first impedance state to the second impedance state in response to a change in one or more environmental conditions.

3. The sensor device of claim 2, wherein the bridge is configured such that the conductive polymer changes from the first impedance state to the second impedance state in response to a change in exposure to a sterilant.

4. A sensor device according to claim 3, wherein the sterilant comprises steam or hydrogen peroxide.

5. The sensor device of any one of the preceding claims, the bridge further comprising a polymeric binder, wherein the metal or metal-containing particles and the conductive polymer are dispersed in the polymeric binder.

6. The sensor device of claim 5, wherein the metal or metal-containing particles comprise aluminum, tin, bismuth, nickel, lead, indium, chromium, gallium, iron, vanadium, cadmium, titanium, zirconium, nob, tungsten, thallium, germanium, lanthanides, or alloys thereof.

7. The sensor device of claim 5, 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, nob, tungsten, thallium, or oxides and complexes thereof.

8. The sensor device of any one of the preceding claims, wherein the first electrode and the second electrode are electrically coupled to the bridge such that a first resistance can be measured across the first electrode and the second electrode when the conductive polymer is in the first impedance state, and a second resistance can be measured across the first electrode and the second electrode when the conductive polymer is in the second impedance state, and wherein the first resistance is different from the second resistance.

9. The sensor device of any one of the preceding claims, wherein the conductive polymer comprises repeating units of: aniline, acetylene, pyrrole, phenylene, phenylenevinylene, phenylsulfide, fluorene, pyrene, azulene, naphthalene, carbazole, indole, thiophene, ethylenedioxythiophene, or combinations thereof.

10. The sensor device of any one of the preceding claims, wherein the conductive polymer comprises polyaniline.

11. A sterilization system, the system comprising:

a sterilizer having a chamber configured to receive a medical device for sterilization; and

A sensor device according to any one of the preceding claims, disposed in the chamber.

12. A method, the method comprising:

providing a sensor device according to any one of claims 1 to 11;

the sensor device is exposed to a sterilant during sterilization.

13. The method of claim 12, wherein the sterilant comprises steam or hydrogen peroxide.

14. A sensor device, the sensor device comprising:

a sterilant responsive switch, said sterilant responsive switch comprising:

first and second electrodes, each of the first and second electrodes having first and second ends, the first end electrically coupled to an electrical circuit;

a conductive polymer having a first state and a second state;

conductive particles; and

the polymer binder is used in the form of a polymeric binder,

wherein the conductive polymer is capable of transitioning from being in the first state to being in the second state upon contact with a sterilant.