Test device, disinfection monitoring system and method

Abstract

A test device for monitoring disinfection with a steam disinfectant within a chamber is provided. The test device includes a test stack. The test stack includes an inlet layer, the inlet layer including an inlet aperture. The test stack also includes a sensor layer that is spaced apart from the inlet layer. The sensor layer includes at least one pair of electrodes disposed on the sensor layer. The test stack also includes at least one sensor coating disposed on at least a portion of the sensor layer and including an electroactive polymer. The test stack also includes an intermediate layer disposed between the inlet layer and the sensor layer. The intermediate layer is disposed to fluidly connect the inlet aperture with the at least one sensor coating. The intermediate layer is configured to allow vapor sanitizer received from the inlet aperture to flow to the at least one sensor coating.

Description

Technical Field

[0001] The present disclosure relates generally to sterilization, and more particularly to a test device for monitoring sterilization, a sterilization monitoring device including the test device, and a method for monitoring sterilization within a chamber. Background Art

[0002] Sterilization of medical and hospital equipment may not be effective unless the steam sterilizer is in contact with all surfaces of the material being sterilized under the appropriate combination of time, temperature and steam quality. In steam sterilizers such as pre-vacuum steam sterilizers and gravity displacement steam sterilizers, the sterilization process is performed in three main stages. In the first stage, air is removed, including air trapped in any porous material being processed. The first stage is therefore an air removal stage. The second stage is the sterilization stage, in which the load (i.e., the item being sterilized) is subjected to steam under pressure for a recognized, predetermined combination of time and temperature to achieve sterilization. The third stage is the drying stage, in which condensation formed in the first two stages is removed by evacuating the chamber.

[0003] Any air that is not removed from the sterilizer during the air removal phase of the cycle, or that leaks into the sterilizer during the pressure phase below atmospheric pressure due to, for example, a failure of a gasket, valve, or seal, may form air pockets in any porous material present. Such air pockets may create a barrier to steam penetration, thereby preventing adequate sterilization conditions from being achieved for all surfaces of the load during the sterilization phase. For example, these air pockets may prevent steam from reaching the inner layers of materials such as medical linens or fabrics. In some other examples, these air pockets may prevent steam from penetrating hollow spaces of tubes, catheters, syringe needles, etc. In addition, non-condensable gases (usually air) present within the sterilizer are poor sterilants and may reduce sterilization efficacy. The volume percentage of non-condensable gases in steam should be less than or equal to 3.5%. Therefore, the presence of air pockets and / or non-condensable gases may affect the steam quality of the steam sterilizer. Therefore, due to reduced steam quality, proper sterilization may not be achieved. Several other factors that may affect steam quality include insufficient steam supply, water quality, degassing, design of the sterilizer chamber, etc. Summary of the invention

[0004] In a first aspect, the present disclosure provides a test device for monitoring sterilization using a steam sterilizer in a chamber. The test device includes a test stack, the test stack defining a main plane and a perimeter. The test stack includes an inlet layer, the inlet layer including an inlet hole extending through the inlet layer. The inlet hole is fluidly connected to the chamber. The test stack also includes a sensor layer, the sensor layer is spaced apart from the inlet layer. The sensor layer includes at least one pair of electrodes disposed on the sensor layer. The test stack also includes at least one sensor coating, the at least one sensor coating is disposed on at least a portion of the sensor layer and includes the electroactive polymer. The at least one sensor coating is spaced apart from the inlet hole at least along the main plane of the test stack. The at least one sensor coating is electrically coupled to the at least one pair of electrodes. The test stack also includes an intermediate layer, the intermediate layer is disposed between the inlet layer and the sensor layer. The intermediate layer fluidly connects the inlet hole to the at least one sensor coating. The intermediate layer is configured to allow the steam sterilizer received from the inlet hole to flow to the at least one sensor coating. The at least one sensor coating is configured to change the electrical impedance across the at least one pair of electrodes when the steam sterilizer contacts the at least one sensor coating.

[0005] In a second aspect, the present disclosure provides a disinfection monitoring system comprising the test device of the first aspect. The disinfection monitoring system further comprises a reader configured to at least partially receive the test device therein for measuring electrical impedance across the at least one pair of electrodes.

[0006] In a third aspect, the present disclosure provides a disinfection system, the disinfection system comprising the disinfection monitoring system of the second aspect. The disinfection system also includes a disinfector, the disinfector including a chamber, the chamber being configured to receive the test device therein. The disinfector is configured to perform a disinfection process on the test device using a steam sterilizer in the chamber.

[0007] In a fourth aspect, the present disclosure provides a method for monitoring sterilization within a chamber using the test device of the first aspect. The method includes: arranging the test device within the chamber. The method also includes: performing a sterilization process on the test device using a steam sterilizer. The method also includes: removing the test device from the chamber. The method also includes: at least partially inserting the test device into a reader for measuring electrical impedance across the at least one pair of electrodes.

[0008] In a fifth aspect, the present disclosure provides a test device for monitoring sterilization using a steam sterilizer in a chamber. The test device includes a test stack, the test stack defining a major plane and a perimeter. The test stack includes a top layer, the top layer including: a first major surface, the first major surface being proximal to the chamber; a second major surface, the second major surface being opposite to the first major surface; and an inlet hole, the inlet hole extending from the first major surface at least partially through the top layer and being arranged to be fluidly connected to the chamber. The top layer is combined with at least one intermediate path, the at least one intermediate path being at least partially aligned with the inlet hole and being arranged to be fluidly connected to the inlet hole. The at least one intermediate path defines a path length along the major plane and a path depth normal to the major plane. The at least one intermediate path extends from the second major surface at least partially through the top layer along the path depth. The at least one intermediate path is spaced apart from the perimeter of the test stack. The test stack also includes a sensor layer, the sensor layer being arranged adjacent to the second major surface of the top layer. The sensor layer includes at least one pair of electrodes arranged on the sensor layer. The test stack also includes at least one sensor coating disposed on at least a portion of the sensor layer and including the electroactive polymer. The at least one intermediate path of the top layer extends from the inlet hole to the at least one sensor coating at least along the path length, such that the at least one intermediate path fluidly connects the inlet hole with the at least one sensor coating. The at least one sensor coating is electrically coupled to the at least one pair of electrodes on the sensor layer. The top layer is configured to allow the steam sterilant to flow from the inlet hole to the at least one sensor coating. The at least one sensor coating is configured to change the electrical impedance across the pair of electrodes when the steam sterilant contacts the at least one sensor coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The exemplary embodiments disclosed herein may be more completely understood by considering the following detailed description in conjunction with the following drawings. The drawings are not necessarily drawn to scale. The same numerals used in the drawings represent similar components. However, it should be understood that the use of numbers to refer to components in a given figure is not intended to limit the components marked with the same number in another figure.

[0010] Figure 1 is a block diagram of a disinfection system according to an embodiment of the present disclosure;

[0011] Figure 2 According to the embodiments of the present disclosure Figure 1 A top perspective view of a test device for a disinfection system;

[0012] Figure 3 According to an embodiment of the present disclosure, the method includes: Figure 2 The test stack is shown cut along line A-A'. Figure 2A cross-sectional side view of a test device;

[0013] Figure 4 According to the embodiments of the present disclosure Figure 3 Top view of the test stack;

[0014] Figure 5 According to the embodiments of the present disclosure Figure 3 A bottom view of a test stack with some layers not shown;

[0015] Figure 6 Schematically shows an embodiment according to the present disclosure Figure 1 Reader for disinfection system;

[0016] Figure 7 is a bottom view of a test device according to another embodiment of the present disclosure, wherein some layers are not shown;

[0017] Figure 8 is a cross-sectional side view of a test device according to another embodiment of the present disclosure;

[0018] Fig. 9 yes Figure 8 A bottom view of a test device, wherein some layers are not shown;

[0019] Fig.10 is a cross-sectional side view of a test device according to another embodiment of the present disclosure;

[0020] Fig.11 yes Fig.10 A bottom view of a test device, wherein some layers are not shown;

[0021] Fig.12 is a bottom view of a test device according to another embodiment of the present disclosure, wherein some layers are not shown;

[0022] Fig.13 is a bottom view of a test device according to another embodiment of the present disclosure, wherein some layers are not shown;

[0023] Fig.14 is a bottom view of a test device according to another embodiment of the present disclosure, wherein some layers are not shown;

[0024] Fig.15 is a bottom view of a test device according to another embodiment of the present disclosure, wherein some layers are not shown;

[0025] Fig.16 is a cross-sectional side view of a test device according to another embodiment of the present disclosure; and

[0026] Fig.17According to the embodiments of the present disclosure, Figure 2 Flow chart of a method for monitoring sterilization of a test device within a chamber. DETAILED DESCRIPTION

[0027] In the following description, reference is made to the accompanying drawings which form a part thereof, and in which various embodiments are shown by way of illustration. It should be understood that other embodiments are contemplated and may be made without departing from the scope or essence of the present disclosure. Therefore, the following detailed description should not be construed in a limiting sense.

[0028] Steam sterilizers are widely used in medical centers and hospitals to sterilize medical equipment. Frequent testing or monitoring of steam quality can be crucial to ensure the safe use of medical equipment in medical treatment. In other words, before subjecting the steam to a given load (i.e., medical equipment), regular testing may have to be performed to check the effectiveness of air removal in the air removal phase of the sterilization process. One of the methods for monitoring the steam quality of a steam sterilizer is the Bowie-Dick test. Typically, the Bowie-Dick test uses indicator paper and a test pack formed by stacking freshly washed towels. In some cases, the indicator paper is a chemical indicator paper. In some cases, the indicator paper is a biological indicator paper. In some cases, the test pack used in the Bowie-Dick test includes a disposable test pack.

[0029] Although the conventional technique of performing the Bowie-Dick test by using a test kit is generally considered an adequate procedure for determining the steam quality of a steam sterilizer or the efficacy of the air removal phase of a steam sterilization process, it may face some challenges. A uniform change in the color of the indicator paper indicates that all the air has been removed and replaced by steam. In some cases, the operator may not accurately interpret the color change of the indicator paper, and this may further lead to misclassification of the test results. Therefore, by using a test kit, the Bowie-Dick test may not always provide accurate test results due to human intervention errors that may occur when analyzing the test kit and / or the indicator paper.

[0030] Furthermore, to maintain a record / log of Bowie-Dick test results for one or more sterilizers, an operator may have to perform numerous scans of images of test packages, photocopy the test results, and manually record the test results. Manually maintaining a log of Bowie-Dick test results may be time consuming for an operator. As a result, steam sterilizer throughput may be reduced due to the manual recording of test results. Thus, when performing Bowie-Dick testing using test packages, regularly updating the log of Bowie-Dick test results may be difficult, erroneous, and time consuming. Furthermore, a large amount of paper may also be periodically wasted in order to maintain a log of Bowie-Dick test results.

[0031] The present disclosure relates to a test device for monitoring sterilization using a steam sterilizer in a chamber. The test device includes a test stack, which defines a main plane and a perimeter. The test stack includes an inlet layer, the inlet layer including an inlet hole extending through the inlet layer. The inlet hole is connected to the chamber fluid. The test stack also includes a sensor layer, the sensor layer is spaced apart from the inlet layer. The sensor layer includes at least one pair of electrodes disposed on the sensor layer. The test stack also includes at least one sensor coating, the at least one sensor coating is disposed on at least a portion of the sensor layer and includes the electroactive polymer. The at least one sensor coating is spaced apart from the inlet hole at least along the main plane of the test stack. The at least one sensor coating is electrically coupled to the at least one pair of electrodes. The test stack also includes an intermediate layer, the intermediate layer is disposed between the inlet layer and the sensor layer. The intermediate layer fluidly connects the inlet hole to the at least one sensor coating. The intermediate layer is configured to allow the steam sterilizer received from the inlet hole to flow to the at least one sensor coating. The at least one sensor coating is configured to change the electrical impedance across the at least one pair of electrodes when the steam sterilizer contacts the at least one sensor coating.

[0032] The present disclosure also provides a sterilization system including a sterilizer. The sterilizer includes a chamber configured to receive a test device. The sterilizer is configured to perform a sterilization process on the test device using the steam sterilizer in the chamber.

[0033] To monitor sterilization using a steam sterilizer, the test device is placed in the chamber of the sterilizer and the sterilization process begins. The chamber is indirectly fluidly connected to the at least one sensor coating because the intermediate layer fluidly connects the inlet hole to the at least one sensor coating and the inlet hole to the chamber.

[0034] In the case of any non-condensable gas or air present in the chamber, the air may contact the at least one sensor coating via the intermediate layer, and this may prevent the steam sterilizer from making any contact with the at least one sensor coating. Therefore, during real-time sterilization, in the presence of air, the steam sterilizer may not reach the hollow space and the internal cavity of the medical equipment being sterilized. In the case of no non-condensable gas or air in the chamber, the steam sterilizer may be able to contact the at least one sensor coating via the intermediate layer. Therefore, in the absence of air, the steam sterilizer may reach the hollow space and the internal cavity of the medical equipment being sterilized. In other words, in order for the quality of the steam sterilizer to be acceptable, there should not be any air in the chamber of the sterilizer.

[0035] In some embodiments, the intermediate layer includes a permeable material. The permeability of the permeable material of the intermediate layer is configured to allow the steam sterilant to flow through the intermediate layer so as to connect the inlet hole to the at least one sensor coating fluid. The permeability of the permeable material of the intermediate layer can provide considerable resistance to the flow of steam sterilant through the intermediate layer. Specifically, the permeable material of the intermediate layer can provide resistance, which corresponds to the resistance provided by different routes and channels, and in the real-time disinfection process, the steam sterilant may have to reach the hollow space and internal cavity of the medical equipment along these routes and channels. Therefore, the resistance provided by the permeable material of the intermediate layer can represent the resistance of various flow channels leading to the hidden space of the tube, catheter, syringe needle, etc. The resistance to the flow of steam sterilant provided by the permeable material of the intermediate layer can depend on the various properties of the permeable material.

[0036] In some other embodiments, the intermediate layer further comprises at least one internal channel defining a channel length along the major plane and a channel depth normal to the major plane. The at least one internal channel is spaced apart from the periphery of the test stack. The at least one internal channel extends through the intermediate layer along the channel depth. The at least one internal channel extends from the inlet hole to the at least one sensor coating at least along the channel length, such that the at least one internal channel connects the inlet hole to the at least one sensor coating fluid.

[0037] The at least one internal passage can provide a considerable channel resistance to the flow of steam sterilant through the at least one internal passage. Specifically, the resistance provided by the at least one internal passage can correspond to the resistance provided by different routes and passages, and during the real-time sterilization process, the steam sterilant may have to follow these routes and passages to reach the hollow space and internal cavity of the medical equipment. The resistance to the flow of steam sterilant provided by the at least one internal passage can depend on the shape and size of the at least one internal passage. In addition, the shape and size of the at least one internal passage can vary based on different application attributes.

[0038] In addition, the at least one sensor coating is further configured to change the electrical impedance across the at least one pair of electrodes to exceed a predetermined threshold impedance when in contact with the steam sterilant. The predetermined threshold impedance may be selected based on various application attributes. Thus, when the steam sterilant is in contact with the at least one sensor coating, the electrical impedance across the at least one pair of electrodes exceeds the predetermined threshold impedance. In addition, in the presence of air, the steam sterilant may not contact the at least one sensor coating, and the electrical impedance across the at least one pair of electrodes is below the predetermined threshold impedance.

[0039] The present disclosure also provides a disinfection monitoring system, which includes a test device and a reader, the reader being configured to at least partially receive the test device therein for measuring the electrical impedance across the at least one pair of electrodes. The disinfection monitoring system is a part of the disinfection system of the present disclosure. In addition, the inlet layer and the intermediate layer of the test device at least partially define a cutout disposed at the periphery of the test stack. Each electrode in the at least one pair of electrodes extends at least partially into the cutout. The cutout is configured to at least partially receive one or more terminals of the reader therein for measuring the electrical impedance across the at least one pair of electrodes. The magnitude of the electrical impedance across the at least one pair of electrodes indicates whether there is air in the sterilizer and the steam quality of the steam sterilizer. Once it is determined that the electrical impedance across the at least one pair of electrodes exceeds a predetermined threshold impedance, the reader provides a pass result. In addition, once it is determined that the electrical impedance across the at least one pair of electrodes is lower than a predetermined threshold impedance, the reader provides a fail result. Therefore, the reader can provide an accurate pass or fail result of the steam sterilization process based on a comparison between the predetermined threshold impedance and the electrical impedance across the at least one pair of electrodes.

[0040] In the case where the electrical impedance across the at least one pair of electrodes exceeds a predetermined threshold impedance, the operator may also determine the quantitative relevance of a pass result based on the magnitude of the difference between the electrical impedance and the predetermined threshold impedance. In the case where the electrical impedance across the at least one pair of electrodes does not exceed the predetermined threshold impedance, the operator may also determine the quantitative relevance of a fail result based on the magnitude of the difference between the electrical impedance and the predetermined threshold impedance.

[0041] In addition, the test device is a built-in and independent unit that can be used with any sterilizer. Compared with conventional techniques for monitoring sterilization by using test packs and / or indicator papers and then manually interpreting the color changes of the indicator papers, a sterilization monitoring system including a test device may require minimal manual interpretation to determine the pass / fail result of the sterilization process. Therefore, the test device and sterilization monitoring system of the present disclosure can provide accurate classification of test results, which may otherwise be erroneous due to possible human intervention errors. In addition, since the test device is used here to monitor the steam quality of the steam sterilizer by measuring the electrical impedance across the at least one pair of electrodes, the test device of the present disclosure can be referred to as an electronic test unit or an electronic test card. In some cases, a sterilization monitoring system including a test device and a reader can also provide a digital pass / fail result of the steam quality of the steam sterilizer.

[0042] Compared to conventional techniques for monitoring sterilization, the sterilization monitoring system of the present disclosure can eliminate the need to scan images of test packages (indicator paper), photocopy test results, and manually record test results. In addition, the sterilization monitoring system including the test device can eliminate the need to maintain a record / log of Bowie-Dick test results for one or more sterilizers. This can also reduce the possibility of misplacing various test results of the steam quality of the steam sterilizer. Therefore, the overall production of the sterilizer can be increased due to the minimal manual recording and / or manual maintenance of the test results. The sterilization monitoring system can allow the operator to perform a faster and easier testing process to accurately monitor the steam quality of the steam sterilizer and / or verify whether the air removal in the chamber of the sterilizer is correct. Therefore, the disclosed sterilization monitoring system can improve the efficiency of the sterilizer and reduce the complexity of the process of monitoring the steam quality of the steam sterilizer. In addition, the sterilization monitoring system can also save a large amount of paper that would otherwise be wasted in the conventional techniques for monitoring sterilization.

[0043] Now referring to the accompanying drawings, Figure 1 A block diagram of a sterilization system 100 is illustrated. The sterilization system 100 includes a sterilizer 102, which includes a chamber 104. The chamber 104 may have one or more environmental conditions. In some cases, the environmental conditions may be related to the conditions inside the chamber 104 and may include time, sterilant, temperature, pressure, or a combination thereof. In some embodiments, the chamber 104 may be made of various materials, such as but not limited to steel, metal, polymer, or any other material. The channel 104 is configured to receive a steam sterilizer therein. When steam is used as a steam sterilizer, the purpose of the sterilization process is to contact the steam with all surfaces of the sterilized article at an appropriate temperature for an appropriate period of time.

[0044] The sterilization system 100 may also include a sterilization monitoring system 106. The sterilization monitoring system 106 includes a test device 110 for monitoring sterilization performed using a steam sterilizer in the chamber 104. The chamber 104 is configured to receive the test device 110 therein. The sterilizer 102 is configured to perform a sterilization process on the test device 110 within the chamber 104 using the steam sterilizer.

[0045] Figure 2 1 is a top perspective view of a test device 110 according to an embodiment of the present disclosure. The test device 110 defines mutually orthogonal x-axis, y-axis, and z-axis. The test device 110 includes a test stack 112, which defines a principal plane A1 and a perimeter P. The x- and y-axes are in-plane axes of the test stack 112, while the z-axis is a transverse axis disposed along the thickness of the test stack 112. In other words, the x-axis and y-axis are disposed along the principal plane A1 of the test stack 112, while the z-axis is perpendicular to the principal plane A1 of the test stack 112. The principal plane A1 thus corresponds to the xy plane.

[0046] Figure 3 According to an embodiment of the present disclosure, the method includes: Figure 2 A cross-sectional side view of the test device 110 of the test stack 112 taken along the line AA' shown. The test stack 112 includes an inlet layer 202, which includes an inlet hole 204 extending through the inlet layer 202. In some embodiments, the inlet layer 202 includes polyethylene terephthalate (PET). In addition, in some embodiments, the inlet layer 202 may be made of a metal layer such as aluminum foil, a polymer layer such as polyurethane, or a polyester layer without any limitation. The inlet layer 202 defines a thickness T1 along the z-axis. In some cases, the thickness T1 of the inlet layer is about 10 mils. The inlet layer 202 at least partially forms an outer surface S1 of the test stack 112. In some embodiments, the test stack 112 may also include a graphic layer (not shown) that at least partially forms the outer surface S1 of the test stack 112. The graphic layer may include a label, a product logo, a product specification, etc.

[0047] The inlet hole 204 and the chamber 104 (such as Figure 1 ) fluid connections. Figure 3 In the illustrated embodiment, the inlet hole 204 is circular and thus has a diameter d1. In some other embodiments, based on application properties, the inlet hole 204 can be any other shape, such as square, triangle, rectangle, oval, ellipse, polygon, etc.

[0048] The test stack 112 also includes a sensor layer 206 that is spaced apart from the inlet layer 202. The sensor layer 206 defines a thickness T2 along the z-axis. In some cases, the thickness T2 of the sensor layer 206 is about 3 mils. In some embodiments, the thickness T2 of the sensor layer 206 is about 10% to about 50% of the thickness T1 of the inlet layer 202. In some embodiments, each of the sensor layer 206 and the inlet layer 202 is impermeable to the steam sterilant. Therefore, each of the inlet layer 202 and the sensor layer 206 may not allow fluid (e.g., steam) to pass through.

[0049] The test stack 112 also includes an intermediate layer 208 disposed between the inlet layer 202 and the sensor layer 206. The intermediate layer 208 defines a thickness T3 along the z-axis. In some cases, the thickness T3 of the intermediate layer 208 is about 3 mils. In some embodiments, the thickness T3 of the intermediate layer 208 is about 10% to about 50% of the thickness T1 of the inlet layer 202.

[0050] exist Figure 3 In the illustrated embodiment, the intermediate layer 208 is spaced apart from the inlet layer 202 and is disposed adjacent to the sensor layer 206. In other embodiments, the intermediate layer 208 can be disposed adjacent to the inlet layer 202 such that the intermediate layer 208 at least partially contacts the inlet layer 202. In some embodiments, the intermediate layer 208 is permeable or impermeable to the steam sterilant. Figure 3 In the illustrated embodiment, the middle layer 208 comprises a permeable material. Therefore, the middle layer 208 can allow fluid (e.g., vapor) to pass therethrough. In some embodiments, the permeable material includes nylon, clay, polyvinylidene fluoride (PVDF), soil-loaded membranes, polypropylene blown microfibers (BMF), fiberglass, paper, clay-loaded nonwoven materials, fine sand, or a combination thereof.

[0051] The test stack 112 also includes a first adhesive layer 210 disposed between the inlet layer 202 and the intermediate layer 208. The first adhesive layer 210 bonds the intermediate layer 208 to the inlet layer 202. The inlet hole 204 further extends through the first adhesive layer 210. In an example, the first adhesive layer 210 may include an adhesive with very high adhesion, such as a pressure-sensitive adhesive, for example but not limited to silicone polyurea (SPU), acrylic, silicone, or a rubber-based adhesive. In another example, the adhesive with very high adhesion may include a structural adhesive, such as acrylic, cyanoacrylate, epoxy, polyurethane, or a mixture thereof. The first adhesive layer 210 defines a thickness T4 along the z-axis. In some cases, the thickness T4 of the first adhesive layer 210 is about 2 mils. In some embodiments, the thickness T4 of the first adhesive layer 210 is less than the thickness T3 of the intermediate layer 208.

[0052] The test stack 112 further includes a support layer 216 disposed adjacent to the sensor layer 206 and opposite the intermediate layer 208. The support layer 216 at least partially forms an outer surface S2 of the test stack 112. The outer surface S2 is disposed opposite the outer surface S1 formed by the inlet layer 202.

[0053] In some embodiments, the support layer 216 comprises PET. In some other embodiments, the support layer 216 can be made of a metal layer such as aluminum foil, a polymer layer such as polyurethane, or a polyester layer without any limitation. The support layer 216 defines a thickness T5 along the z-axis. In some cases, the thickness T5 of the support layer 216 is about 10 mils. In some embodiments, the thickness T5 of the support layer 216 can be substantially equal to the thickness T1 of the inlet layer 202. In some embodiments, the support layer 216 is impermeable to the steam sterilizer.

[0054] In some embodiments, the inlet layer 202, the intermediate layer 208, the sensor layer 206 and the support layer 216 at least together form a laminated structure. The test stack 112 also includes a second adhesive layer 218, which is disposed between the sensor layer 206 and the support layer 216. The second adhesive layer 218 bonds the support layer 216 to the sensor layer 206. The second adhesive layer 218 defines a thickness T6 along the z-axis. In some embodiments, the second adhesive layer 218 may have a thickness of about 2 mils. In some embodiments, the second adhesive layer 218 may include an adhesive with very high adhesion. In an example, the thickness T4 of the first adhesive layer 210 and the thickness T6 of the second adhesive layer 218 may be substantially equal to each other. In some embodiments, one or more layers of the test stack 112 may be transparent.

[0055] In some cases, the various layers of test stack 112 may be substantially coextensive with each other in length (i.e., along the y-axis) and width (i.e., along the x-axis). In some other cases, the various layers of test stack 112 may not be completely coextensive with each other in length and width. Figure 3 In the illustrated embodiment, each of the inlet layer 202, the first bonding layer 210, and the intermediate layer 208 have substantially equal lengths for illustrative purposes.

[0056] It should be noted that the edges of all layers of the test stack 112 are sealed to each other to prevent any fluid connection between the interior volume of the test stack 112 and the chamber 104 via the edges of the various layers.

[0057] Figure 4 A top view of a test apparatus 110 including a test stack 112 is illustrated in accordance with an embodiment of the present disclosure. For illustrative purposes, the inlet layer 202 is Figure 4 In addition, for illustrative purposes, the first bonding layer 210 is shown as transparent. Figure 4 Not shown. Figure 4 In the illustrated embodiment, the inlet layer 202 and the intermediate layer 208 have substantially equal lengths (i.e., along the y-axis). However, the inlet layer 202 and the intermediate layer 208 have unequal widths (i.e., along the x-axis). In other embodiments, the inlet layer 202 and the intermediate layer 208 may be substantially coextensive with each other in length and width.

[0058] Figure 5 A bottom view of a test device 110 according to an embodiment of the present disclosure is illustrated, wherein some layers are not shown. Specifically, for illustrative purposes, a support layer 216 and a second bonding layer 218 are shown in FIG. Figure 5 In addition, for illustrative purposes, the sensor layer 206 is Figure 5 is shown as transparent.

[0059] refer to Figure 4 and Figure 5 , the test stack 112 further includes at least one sensor coating 222 disposed on at least a portion of the sensor layer 206. The at least one sensor coating 222 comprises an electroactive polymer. The at least one sensor coating 222 is disposed along at least a major plane A1 ( Figure 2 2 (shown) is spaced apart from the inlet aperture 204. Thus, at least one sensor coating 222 is spaced apart from the inlet aperture 204 at least along the xy plane of the test device 110.

[0060] The intermediate layer 208 fluidly connects the at least one sensor coating 222 with the inlet hole 204. Therefore, the intermediate layer 208 is configured to allow the steam sterilant received from the inlet hole 204 to flow to the at least one sensor coating 222. In addition, the intermediate layer 208 is configured to allow non-condensable gas (e.g., air) to flow from the inlet hole 204 to the at least one sensor coating 222. Because the intermediate layer 208 includes a permeable material, the permeability of the permeable material is configured to allow the steam sterilant to flow through the intermediate layer 208 so as to fluidly connect the inlet hole 204 with the at least one sensor coating 222.

[0061] The permeability of the permeable material of the intermediate layer 208 can provide a considerable resistance to the flow of steam sterilant through the intermediate layer 208. In some cases, the permeable material can provide resistance that corresponds to the resistance provided by the different routes and channels that the steam sterilant may have to follow to reach the hollow spaces and internal cavities of the medical equipment during the real-time sterilization process. Therefore, the resistance provided by the permeable material can represent the resistance of various flow channels leading to hidden spaces of tubes, catheters, syringe needles, etc. The resistance to the flow of steam sterilant provided by the permeable material of the intermediate layer 208 can depend on various properties of the permeable material.

[0062] In some embodiments, the electroactive polymer of at least one sensor coating 222 comprises polyaniline (PANI), trans-polyacetylene, poly(p-phenylene), poly(3-vinylperylene), polypyrrole, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene), poly(2-(3-thienyloxy)ethanesulfonate), polythiophene, or a combination thereof.

[0063] In some embodiments, PANI may be in one of three oxidation states, i.e., colorless emeraldine, emeraldine (salt or base form), and all (nigrosine). Emeraldine may have poor conductivity in base form and may have good conductivity in salt form. In addition, emeraldine salt may be converted into colorless emeraldine salt or all (nigrosine) via redox reaction, reducing the conductivity of the colorless emeraldine salt.

[0064] In some embodiments, at least one sensor coating 222 further comprises tin. In some cases, at least one sensor coating 222 may comprise tin nanoparticles. In some other cases, at least one sensor coating 222 may comprise blended nanoparticles of PANI and aluminum, transition metals, post-transition metals, or combinations thereof.

[0065] refer to Figures 1 to 5 , the sensor layer 206 includes at least one pair of electrodes 236 disposed on the sensor layer 206. In addition, at least one sensor coating 222 is electrically coupled to the at least one pair of electrodes 236. In the illustrated embodiment, a pair of electrodes 236 is shown, however, the test device 110 may include any number of pairs of electrodes 236 depending on the application requirements. Each electrode of the at least one pair of electrodes 236 may include a conductive material. In some embodiments, each electrode of the at least one pair of electrodes 236 includes at least one of silver, carbon, and aluminum.

[0066] In some embodiments, at least a portion of each of the at least one pair of electrodes 236 is disposed between the at least one sensor coating 222 and the sensor layer 206 such that at least one gap G1 is defined between the at least one pair of electrodes 236. The at least one gap G1 is covered by the at least one sensor coating 222.

[0067] In some embodiments, the inlet layer 202 and the intermediate layer 208 at least partially define a cutout C1 disposed at a perimeter P of the test stack 112. Each electrode of the at least one pair of electrodes 236 at least partially extends into the cutout C1.

[0068] In some embodiments, the disinfection monitoring system 106 may also include a rack (not shown) configured to at least partially and removably receive therein a test device 110. The rack may be further configured to removably secure or retain the test device 110. To perform a disinfection monitoring cycle, the rack and the test device 110 at least partially received therein may be placed within the chamber 104 of the disinfector 102.

[0069] The sterilization monitoring system 106 including the test device 110 can also be used for other sterilization methods, such as vaporized hydrogen peroxide sterilization. In addition, the sterilization monitoring system 106 can be used in different types of steam sterilizers that have been manufactured and are currently used in the medical industry.

[0070] The disinfection monitoring system 106 also includes a reader 114 ( Figure 1 ), the reader is configured to at least partially receive a test device 110 therein for measuring an electrical impedance I1 across at least one pair of electrodes 236. Figure 6 The reader 114 according to an embodiment of the present disclosure is schematically shown. Figure 6 In the example embodiment, the test device 110 is received in the reader 114. The value of the electrical impedance I1 may be stored in the memory 116 of the reader 114.

[0071] refer to Figures 1 to 6 , the cutout C1 is configured to at least partially receive therein one or more terminals (not shown) of the reader 114 for measuring the electrical impedance I1 across the at least one pair of electrodes 236. In addition, the at least one sensor coating 222 is configured to change the electrical impedance I1 across the at least one pair of electrodes 236 when the steam sterilant contacts the at least one sensor coating 222. In some embodiments, upon contact with the steam sterilant, the at least one sensor coating 222 is further configured to change the electrical impedance I1 across the at least one pair of electrodes 236 to exceed a predetermined threshold impedance I2 (which may be stored in the memory 116).

[0072] In addition, it should be noted that the electroactive polymer in the at least one sensor coating 222 switches between one impedance state and another impedance state based on the interaction with the steam sterilant. In some embodiments, since the at least one pair of electrodes 236 can be coated with or formed of a conductive material such as silver, carbon, or aluminum, the conductive material can directly react with the at least one sensor coating 222 and convert the emeraldine salt into a colorless emeraldine salt so that the conductivity of the colorless emeraldine salt is reduced. Therefore, based on the redox reaction of the electroactive polymer and the conductive material of the at least one pair of electrodes 236 under the ambient conditions of the chamber 104, the at least one sensor coating 222 can be transformed from one impedance state to another impedance state.

[0073] Furthermore, in some embodiments, upon appropriate exposure of the steam sterilant to the at least one sensor coating 222, the at least one pair of electrodes 236 can switch from an electrically short circuit (i.e., a small impedance between the at least one pair of electrodes 236) to an electrically open circuit state (i.e., a large impedance between the at least one pair of electrodes 236).

[0074] While monitoring the sterilization, once it is determined that the electrical impedance I1 across the at least one pair of electrodes 236 exceeds the predetermined threshold impedance I2, the reader 114 provides a pass result. In addition, once it is determined that the electrical impedance I1 across the at least one pair of electrodes 236 is below the predetermined threshold impedance I2, the reader 114 provides a fail result. Therefore, the reader 114 can provide an accurate pass or fail result of the steam sterilization process based on a comparison between the predetermined threshold impedance I2 and the electrical impedance I1 across the at least one pair of electrodes 236.

[0075] In the case where the electrical impedance I1 across the at least one pair of electrodes 236 exceeds the predetermined threshold impedance I2, the operator may also determine the quantitative relevance of a pass result based on the magnitude of the difference between the electrical impedance I1 and the predetermined threshold impedance I2. In the case where the electrical impedance I1 across the at least one pair of electrodes 236 does not exceed the predetermined threshold impedance I2, the operator may also determine the quantitative relevance of a fail result based on the magnitude of the difference between the electrical impedance I1 and the predetermined threshold impedance I2.

[0076] In addition, the test device 110 is a built-in and independent unit that can be used with any sterilizer. Compared with conventional techniques for monitoring sterilization by using test packs and / or indicator paper and then manually interpreting the color change of the indicator paper, the sterilization monitoring system 106 including the test device 110 may require minimal manual interpretation to determine the pass / fail result of the sterilization process. Therefore, the test device 110 and the sterilization monitoring system 106 of the present disclosure can provide accurate classification of test results, which may otherwise be wrong due to possible human intervention errors. In addition, since the test device 110 is used here to monitor the steam quality of the steam sterilizer by measuring the electrical impedance I1 across at least one pair of electrodes 236, the test device 110 of the present disclosure can be referred to as an electronic test unit or an electronic test card. In some cases, the sterilization monitoring system 106 including the test device 110 and the reader 114 can also provide a digital pass / fail result of the steam quality of the steam sterilizer.

[0077] Compared to conventional techniques for monitoring sterilization, the sterilization monitoring system 106 of the present disclosure can eliminate the need to scan images of test packages (indicator paper), photocopy test results, and manually record test results. In addition, the sterilization monitoring system 106 including the test device 110 can eliminate the need to maintain a record / log of Bowie-Dick test results for one or more sterilizers. This can also reduce the possibility of misplacing various test results of the steam quality of the steam sterilizer. Therefore, the overall throughput of the sterilizer 102 can be increased due to the minimal manual recording and / or manual maintenance of the test results. The sterilization monitoring system 106 can allow the operator to conduct a faster and easier testing process to accurately monitor the steam quality of the steam sterilizer and / or verify whether the air removal in the chamber 104 of the sterilizer 102 is correct. Therefore, the disclosed sterilization monitoring system 106 can improve the efficiency of the sterilizer 102 and reduce the complexity of the process of monitoring the steam quality of the steam sterilizer. In addition, the sterilization monitoring system 106 can also save a large amount of paper that would otherwise be wasted in conventional techniques for monitoring sterilization.

[0078] Figure 7 A bottom view of a test device 111 according to another embodiment of the present disclosure is illustrated. The test device 111 is substantially similar to Figure 4 and Figure 5 The test apparatus 110 is illustrated in FIG. 1 , wherein common components are denoted by the same reference numerals. Figure 7 In the illustrated embodiment, the support layer 216 and the second bonding layer 218 are not shown for illustrative purposes. Figure 7 In addition, the functional advantages of the test device 111 are substantially the same as those of the test device 110 .

[0079] In the test device 111, each electrode 236 of the at least one pair of electrodes 236 includes: an elongated portion 238 extending from the at least one sensor coating 222 toward the perimeter P of the test stack 112; and a plurality of protrusions 240 extending from the elongated portion 238 and inclined to the elongated portion. Figure 7 In the illustrated embodiment, the plurality of protrusions 240 are disposed in the major plane A1 of the test stack 112 and extend perpendicularly from the elongated portion 238 of each electrode in the at least one pair of electrodes 236. Figure 7 In the embodiment, each protrusion 240 has a substantially rectangular shape. However, each protrusion 240 may have any suitable alternative shape, such as a triangle, an ellipse, a polygon, an oval, a circle, etc.

[0080] The plurality of protrusions 240 of one electrode of the at least one pair of electrodes 236 and the protrusions 240 of the other electrode of the at least one pair of electrodes 236 extend toward each other and define a plurality of gaps G1 therebetween. In other words, the plurality of protrusions 240 extending from one of the elongated portions 238 of the at least one pair of electrodes 236 and the plurality of protrusions 240 extending from the elongated portion 238 of the other electrode of the at least one pair of electrodes 236 extend toward each other and define a plurality of gaps G1 therebetween. The plurality of protrusions 240 of each electrode 236 of the at least one pair of electrodes 236 form a trapezoidal configuration.

[0081] In addition, for illustrative purposes, the plurality of gaps G1 are shown to be equal to each other. However, in some cases, the plurality of gaps G1 may also be different from each other. In addition, each gap G1 from the plurality of gaps G1 is defined between a corresponding protrusion 240 of the plurality of protrusions 240 from one electrode of the at least one pair of electrodes 236 and a corresponding protrusion 240 of the plurality of protrusions 240 from the other electrode of the at least one pair of electrodes 236.

[0082] exist Figure 7 In the illustrated embodiment, at least one sensor coating 222 is a single sensor coating 222. In addition, at least one pair of electrodes 236 is a single pair of electrodes 236. Thus, in the testing device 111, the plurality of gaps G1 are covered by a single sensor coating 222.

[0083] Figure 8 is a cross-sectional side view of a test device 113 according to another embodiment of the present disclosure. The test device 113 is substantially similar to Figure 3 The test device 110 is shown in FIG. 1 , wherein common components are denoted by the same reference numerals. In addition, the test device 113 includes a substantially similar Figure 31 . The cross-sectional side view of the test device 113 is taken along Figure 2 The line AA' is shown. Fig. 9 A bottom view of the test device 113 is illustrated, with some layers not shown. Specifically, for illustrative purposes, the support layer 216 and the second bonding layer 218 are Fig. 9 In addition, for illustrative purposes, the sensor layer 206 is Fig. 9 In addition, the functional advantages of the test device 113 are substantially the same as those of the test device 110 .

[0084] refer to Figure 8 and Fig. 9 In the test stack 112 ′ of the test device 113 , the middle layer 208 of the test device 113 includes at least one internal channel 220 , which defines a channel length L1 ( L1 ) along the main plane A1 . Fig. 9 ) and the channel depth H1 normal to the main plane A1 ( Figure 2 ). In some embodiments, at least one internal channel 220 is interchangeably referred to as "at least one intermediate path 220". In some embodiments, the channel length L1 is interchangeably referred to as "path length L1". In some embodiments, the channel depth H1 is interchangeably referred to as "path depth H1". The at least one internal channel 220 is spaced apart from the perimeter P of the test stack 112'. The at least one internal channel 220 extends through the intermediate layer 208 along the channel depth H1. In addition, the at least one internal channel 220 extends from the inlet hole 204 to the at least one sensor coating 222 at least along the channel length L1, so that the at least one internal channel 220 fluidly connects the inlet hole 204 with the at least one sensor coating 222. Therefore, the at least one internal channel 220 is configured to allow steam sterilant to flow from the inlet hole 204 to the at least one sensor coating 222. In addition, the at least one internal channel 220 is also configured to allow non-condensable gas (e.g., air) to flow from the inlet hole 204 to the at least one sensor coating 222.

[0085] At least one internal channel 220 defines a width W1 extending perpendicular to the channel depth H1. In some embodiments, the width W1 of at least one internal channel 220 is less than or equal to the diameter d1 of the inlet hole 204. Fig. 9 In the illustrated embodiment, at least one internal channel 220 is linear. In some other embodiments, at least one internal channel 220 may be at least partially non-linear along the channel length L1. In addition, the shape and size of at least one internal channel 220 may vary based on different application attributes.

[0086] The at least one internal channel 220 can provide a substantial passage resistance to the flow of steam sterilant through the at least one internal channel 220. Specifically, the resistance provided by the at least one internal channel 220 can correspond to the resistance provided by the different routes and channels that the steam sterilant may have to follow to reach the hollow spaces and internal cavities of the medical equipment during the real-time sterilization process. The resistance to the flow of steam sterilant provided by the at least one internal channel 220 can depend on the shape and size of the at least one internal channel 220.

[0087] Fig.10 is a cross-sectional side view of a test device 115 according to another embodiment of the present disclosure. The test device 115 is substantially similar to Figure 8 The test device 113 is shown in FIG. 1 , wherein common components are denoted by the same reference numerals. In addition, the test device 115 includes a substantially similar Figure 8 1. The cross-sectional side view of the test device 115 is taken along Figure 2 The line AA' is shown. Fig.11 A bottom view of the test device 115 is illustrated, with some layers not shown. Specifically, for illustrative purposes, the support layer 216 and the second bonding layer 218 are shown in FIG. Fig.11 In addition, for illustrative purposes, the sensor layer 206 is Fig.11 In addition, the functional advantages of the test device 115 are substantially the same as those of the test device 113 .

[0088] refer to Fig.10 and Fig.11 In the test device 115, the middle layer 208 comprises an impermeable material that does not allow fluid (e.g., vapor) to pass therethrough. Therefore, vapor flowing through the inlet hole 204 must flow through at least one internal channel 220 to reach the at least one sensor coating 222. In some embodiments, the middle layer 208 of the test stack 112" comprises PET.

[0089] Fig.12 A bottom view of a test device 117 according to another embodiment of the present disclosure is illustrated, with some layers not shown. The test device 117 is substantially similar to Figure 7 The test device 111 is shown in FIG. 1 , wherein common components are denoted by the same reference numerals. In addition, the test device 117 includes a substantially similar Figure 3 1 . The test stack 117 ′ of the test stack 112 of the test device 110 is shown in FIG. Fig.12 In the illustrated embodiment, the support layer 216 and the second bonding layer 218 are not shown for illustrative purposes. Fig.12 In addition, the functional advantages of the test device 117 are substantially the same as those of the test device 111 .

[0090] and Figure 7 Compared to the test device 111 of FIG. 1 , the test device 117 also includes at least one internal channel 320 extending from the inlet hole 204 to the at least one sensor coating 222. In some embodiments, the geometric characteristics of the at least one internal channel 320 are similar to those of the sensor coating 222. Figure 8 and Fig. 9 The geometric characteristics of at least one internal channel 220 of the test device 113 are substantially the same. The length of at least one internal channel 320 may be different from the channel length L1 ( Fig.11 ). Fig.12 In the illustrated embodiment, the intermediate layer 208 is permeable. In other embodiments, the intermediate layer 208 may be impermeable.

[0091] Fig.13 is a bottom view of a test device 109 according to another embodiment of the present disclosure, wherein some layers are not shown. The test device 109 is substantially similar to Figures 3 to 5 The test apparatus 110 is illustrated in FIG. 1 , wherein common components are denoted by the same reference numerals. Fig.13 In the embodiment, for illustrative purposes, only at least one pair of electrodes 236, sensor layer 206 and at least one sensor coating 222 are shown. Figures 3 to 5 The functional advantages of the test device 110 are basically the same.

[0092] exist Fig.13 In the test device 109 of the present invention, at least one pair of electrodes 236 includes multiple pairs of electrodes 236-1, 236-2, ... 236-N (collectively referred to as "electrode pairs 236") that define multiple gaps G1. In some embodiments, the multiple pairs of electrodes 236-1, 236-2, ... 236-N are spaced apart from each other in the main plane A1. In some embodiments, the multiple pairs of electrodes 236-1, 236-2, ... 236-N are arranged adjacent to each other along the elongated axis TA.

[0093] Furthermore, each gap of the plurality of gaps G1 is defined between one electrode 236 of a corresponding pair of electrodes 236 from the plurality of pairs of electrodes 236-1, 236-2, ... 236-N and another electrode 236 of a corresponding pair of electrodes 236 from the plurality of pairs of electrodes 236-1, 236-2, ... 236-N.

[0094] Continue to refer Fig.13Each electrode 236 in the plurality of pairs of electrodes 236-1, 236-2, ... 236-N includes a first portion 242 extending from at least one sensor coating 222 and an orthogonal second portion 244 extending from the first portion 242 toward the periphery P. Each of the plurality of gaps G1 is defined between the first portions 242 in the corresponding pair of electrodes 236. Fig.13 In the illustrated embodiment, at least one sensor coating 222 is a single sensor coating 222. The plurality of gaps G1 are covered by a single sensor coating 222. It should be noted that Fig.13 Only five pairs of electrodes 236 are illustrated in FIG. However, in some other embodiments, at least one pair of electrodes 236 may include any number of electrode pairs 236.

[0095] Fig.14 is a bottom view of a test device 107 according to another embodiment of the present disclosure, wherein some layers are not shown. The test device 107 is substantially similar to Fig.13 The test device 109 is illustrated in FIG. 1 , wherein common components are denoted by the same reference numerals. Fig.14 In the embodiment, for illustrative purposes, only at least one pair of electrodes 236, sensor layer 206 and at least one sensor coating 222 are shown. Fig.13 The functional advantages of the test device 109 are basically the same.

[0096] In the test device 107, at least one sensor coating 222 includes a plurality of sensor coatings 222-1, 222-2, ... 222-N (collectively referred to as "sensor coatings 222") corresponding to the plurality of gaps G1 and spaced apart from each other. Each gap in the plurality of gaps G1 is covered by a corresponding sensor coating 222 from the plurality of sensor coatings 222-1, 222-2, ... 222-N. In addition, Fig.14 In the illustrated embodiment, multiple pairs of electrodes 236-1, 236-2, ... 236-N are disposed adjacent to each other along the elongated axis TA such that multiple gaps G1 and multiple sensor coatings 222-1, 222-2, ... 222-N are arranged along the elongated axis TA.

[0097] Fig.15 A bottom view of a test device 119 according to another embodiment of the present disclosure is illustrated, with some layers not shown. The test device 119 is functionally equivalent to Figure 8 and Fig. 9 The test device 113 is shown in the example, wherein common components are indicated by the same reference numerals. In addition, the functional advantages of the test device 119 are similar to those of the Figure 8 and Fig. 9 The functional advantages of the test equipment 113 are basically the same. Fig.15In the illustrated embodiment, the support layer 216 and the second bonding layer 218 are not shown for illustrative purposes. In addition, for illustrative purposes, the sensor layer 206, the intermediate layer 208 and the first bonding layer 210 are shown in FIG. Fig.15 is shown as transparent.

[0098] In the test device 119, at least one internal channel 220 includes a plurality of linear portions 248 connected to each other. In addition, adjacent linear portions 248 from the plurality of linear portions 248 are inclined toward each other. In some embodiments, adjacent linear portions 248 may be perpendicular to each other. In some cases, the plurality of linear portions 248 may have different lengths relative to each other.

[0099] Furthermore, in the testing device 119, at least one pair of electrodes 236 is included in the main plane A1 ( Figure 2 ) are spaced apart from each other in a plurality of pairs of electrodes 236-1, 236-2, ... 236-N (also shown in Fig.14 At least one sensor coating 222 includes a plurality of sensor coatings 222-1, 222-2, ... 222-N (also shown in Fig.14 Each sensor coating of the plurality of sensor coatings 222-1, 222-2, ... 222-N is electrically coupled to a corresponding pair of electrodes 236 from the plurality of pairs of electrodes 236-1, 236-2, ... 236-N.

[0100] In addition, in the test device 119, at least one internal channel 220 includes a plurality of internal channels 220-1, 220-2, ... 220-N (collectively referred to as "internal channels 220") corresponding to the plurality of sensor coatings 222-1, 222-2, ... 222-N and spaced apart from each other. Each internal channel 220 from the plurality of internal channels 220-1, 220-2 ... 220-N fluidly connects the inlet hole 204 with a corresponding sensor coating 222 from the plurality of sensor coatings 222-1, 222-2, ... 222-N. Fig.15 In the illustrated embodiment, the at least one internal channel 220 includes a total of three internal channels 220. In other embodiments, the at least one internal channel 220 may include any number of internal channels 220. The shapes and sizes of the plurality of internal channels 220-1, 220-2, ... 220-N may vary based on different application attributes.

[0101] Fig.16 is a cross-sectional view of a test device 121 according to another embodiment of the present disclosure. The test device 121 is substantially similar to Figure 8 and Fig. 9The test device 113 is shown in FIG. 1 , wherein common components are denoted by the same reference numerals. In addition, the test device 121 includes a substantially similar Figure 8 1 and 2 , respectively, of the test stack 112 ′ and the test stack 122 of the test device 113 , wherein common components are denoted by the same reference numerals.

[0102] However, in the test device 121, the test stack 122 includes a top layer 152 (rather than Figure 3 104, and a first bonding layer 210 and an intermediate layer 208 in the test stack 112 of the present invention, the top layer 152 includes a first major surface 154 proximate to the chamber 104 and a second major surface 156 opposite the first major surface 154. The top layer 152 also includes an inlet hole 204 that extends at least partially through the top layer 152 from the first major surface 154 and is configured to be fluidly connected to the chamber 104. The top layer 152 incorporates at least one intermediate path 220 that is at least partially aligned with the inlet hole 204 and is configured to be fluidly connected to the inlet hole. The at least one intermediate path 220 extends at least partially through the top layer 152 from the second major surface 156 along a path depth H1. The at least one intermediate path 220 is spaced apart from the perimeter P of the test stack 122.

[0103] Additionally, the sensor layer 206 is disposed adjacent to the second major surface 156 of the top layer 152. The inlet aperture 204 is disposed adjacent to at least one sensor coating 222 ( Figure 4 and Figure 5 In addition, at least one intermediate path 220 of the top layer 152 is at least along the path length L1 ( Fig. 9 204 to the at least one sensor coating 222 such that at least one intermediate path 220 fluidly connects the inlet hole 204 with the at least one sensor coating 222.

[0104] The top layer 152 is configured to allow steam sterilant received from the inlet hole 204 to flow to the at least one sensor coating 222. Thus, in the presence of steam sterilant or in the absence of air without any non-condensable gases, the at least one sensor coating 222 is configured to change the electrical impedance I1 (φ) across the at least one pair of electrodes 236 when the steam sterilant contacts the at least one sensor coating 222. Figure 1 In some embodiments, at least some portion of the top layer 152 can be permeable to the steam sterilant to fluidly connect the inlet hole 204 with the sensor layer 206.

[0105] In some embodiments, the test stack 122 also includes a support layer 216 disposed adjacent to the sensor layer 206 and opposite the top layer 152. The support layer 216 at least partially forms an outer surface S2 of the test stack 122. In some embodiments, the test stack 122 also includes a bonding layer 318 disposed between the sensor layer 206 and the support layer 216. The bonding layer 318 bonds the support layer 216 to the sensor layer 206. In some examples, the bonding layer 318 is substantially similar to the second bonding layer 218 ( Figure 8 In some embodiments, the test stack 122 further includes a bonding layer 310 disposed between the sensor layer 206 and the top layer 152. The bonding layer 310 bonds the top layer 152 to the sensor layer 206. The bonding layer 310 is substantially similar to the first bonding layer 210 ( Figure 8 as shown).

[0106] Fig.17 An example of a method for using the test device 110 ( Figure 2 ) to monitor chamber 104 ( Figure 1 ) is a flowchart of a method 500 for disinfection. The method 500 may also be performed by the test device 111 ( Figure 7 As shown), test equipment 113 ( Figure 8 As shown), test equipment 115 ( Fig.10 As shown), test equipment 117 ( Fig.12 As shown), test equipment 109 ( Fig.13 As shown), test equipment 107 ( Fig.14 As shown), test equipment 119 ( Fig.15 shown) and test equipment 121 ( Fig.16 shown) to achieve this.

[0107] refer to Figure 2 and Fig.17 At step 502, method 500 includes: positioning test device 110 within chamber 104. At step 504, method 500 includes: performing a sterilization process using a steam sterilizer on test device 110. At step 506, method 500 includes: removing test device 110 from chamber 104. At step 508, method 500 includes: at least partially inserting test device 110 into reader 114 for measuring electrical impedance I1 across pair of electrodes 236.

[0108] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0109] Although specific embodiments have been illustrated and described herein, it will be appreciated by those skilled in the art that a variety of alternative and / or equivalent implementations may replace the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptation or variation of the specific embodiments discussed herein. Therefore, the present disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. A test device for monitoring sterilization using a steam sterilizer in a chamber, the test device comprising: A test stack, the test stack defining a main plane and a perimeter, the test stack comprising: an inlet layer, the inlet layer comprising an inlet aperture extending through the inlet layer, wherein the inlet aperture is in fluid connection with the chamber; a sensor layer spaced apart from the inlet layer, wherein the sensor layer includes at least one pair of electrodes disposed on the sensor layer; at least one sensor coating disposed on at least a portion of the sensor layer and comprising an electroactive polymer, wherein the at least one sensor coating is spaced apart from the inlet aperture along at least a major plane of the test stack, wherein the at least one sensor coating is electrically coupled to the at least one pair of electrodes; and an intermediate layer disposed between the inlet layer and the sensor layer, wherein the intermediate layer fluidly connects the inlet aperture with the at least one sensor coating; wherein the intermediate layer is configured to allow steam sterilant received from the inlet aperture to flow to the at least one sensor coating, and wherein the at least one sensor coating is configured to change an electrical impedance across the at least one pair of electrodes when the steam sterilant contacts the at least one sensor coating. 2 . The test apparatus of claim 1 , wherein the intermediate layer is spaced apart from the inlet layer and disposed adjacent to the sensor layer.

3. A test device according to claim 1, wherein the entry layer and the intermediate layer at least partially define a cutout disposed at a perimeter of the test stack, wherein each electrode of the at least one pair of electrodes extends at least partially into the cutout, and wherein the cutout is configured to at least partially receive one or more terminals of a reader therein for measuring an electrical impedance across the at least one pair of electrodes.

4. The testing device according to claim 1, wherein at least a portion of each electrode of the at least one pair of electrodes is disposed between the at least one sensor coating and the sensor layer such that at least one gap is defined between the at least one pair of electrodes, and wherein the at least one gap is covered by the at least one sensor coating.

5. The testing device of claim 1 , wherein each electrode of the at least one pair of electrodes comprises: an elongated portion extending from the at least one sensor coating toward a perimeter of the test stack; and a plurality of protrusions extending from and inclined to the elongated portion, wherein the plurality of protrusions of one electrode of the at least one pair of electrodes and the plurality of protrusions of the other electrode of the at least one pair of electrodes extend toward each other and define a plurality of gaps therebetween, and wherein each of the plurality of gaps is defined between a corresponding protrusion of the plurality of protrusions from the one electrode of the at least one pair of electrodes and a corresponding protrusion of the plurality of protrusions from the other electrode of the at least one pair of electrodes.

6. The testing device of claim 5, wherein the at least one sensor coating is a single sensor coating, wherein the at least one pair of electrodes is a single pair of electrodes, and wherein the plurality of gaps are covered by the single sensor coating.

7. The test apparatus of claim 5, wherein the plurality of protrusions are disposed in a major plane of the test stack and extend perpendicularly from the elongated portion of each electrode of the at least one pair of electrodes.

8. The testing device of claim 1 , wherein the at least one pair of electrodes comprises a plurality of pairs of electrodes defining a plurality of gaps, and wherein each of the plurality of gaps is defined between one electrode from a corresponding pair of electrodes from the plurality of pairs of electrodes and another electrode from the corresponding pair of electrodes from the plurality of pairs of electrodes.

9. A testing device according to claim 8, wherein each electrode of the plurality of pairs of electrodes includes a first portion extending from the at least one sensor coating and an orthogonal second portion extending from the first portion toward the periphery, and wherein each of the plurality of gaps is defined between the first portions in the corresponding pair of electrodes.

10. The testing device of claim 8, wherein the at least one sensor coating is a single sensor coating, and wherein the plurality of gaps are covered by the single sensor coating.

11. The testing device of claim 8, wherein the at least one sensor coating comprises a plurality of sensor coatings corresponding to the plurality of gaps and spaced apart from one another, and wherein each of the plurality of gaps is covered by a corresponding sensor coating from the plurality of sensor coatings.

12. The testing apparatus of claim 11, wherein the plurality of pairs of electrodes are disposed adjacent to one another along an elongated axis such that the plurality of gaps and the plurality of sensor coatings are arranged along the elongated axis.

13. The test device of claim 1, wherein the intermediate layer comprises a permeable material, and wherein the permeability of the permeable material of the intermediate layer is configured to allow the steam sterilant to flow through the intermediate layer so as to fluidly connect the inlet hole with the at least one sensor coating.

14. The test apparatus of claim 13, wherein the permeable material comprises nylon, clay, polyvinylidene fluoride (PVDF), soil-loaded membrane, polypropylene blown microfiber (BMF), fiberglass, paper, clay-loaded nonwoven material, fine sand, or combinations thereof.

15. A test device according to claim 1, wherein the intermediate layer further includes at least one internal channel defining a channel length along the major plane and a channel depth normal to the major plane, wherein the at least one internal channel is spaced apart from a periphery of the test stack, wherein the at least one internal channel extends through the intermediate layer along the channel depth, wherein the at least one internal channel extends at least along the channel length from the inlet hole to the at least one sensor coating, such that the at least one internal channel connects the inlet hole to the at least one sensor coating fluid.

16. The test apparatus of claim 15, wherein the width of the at least one internal passage is less than or equal to the diameter of the inlet aperture.

17. The testing device of claim 15, wherein the at least one internal channel is linear.

18. The testing device of claim 15, wherein the at least one internal channel comprises a plurality of linear sections connected to each other, and wherein adjacent linear sections from the plurality of linear sections are inclined with respect to each other.

19. A testing device according to claim 15, wherein the at least one pair of electrodes includes multiple pairs of electrodes spaced apart from each other in the main plane, wherein the at least one sensor coating includes multiple sensor coatings, the multiple sensor coatings correspond to the multiple pairs of electrodes and are spaced apart from each other, wherein each of the multiple sensor coatings is electrically coupled to a corresponding pair of electrodes from the multiple pairs of electrodes, wherein the at least one internal channel includes multiple internal channels, the multiple internal channels correspond to the multiple sensor coatings and are spaced apart from each other, and wherein each internal channel from the multiple internal channels connects the inlet hole with a corresponding sensor coating fluid from the multiple sensor coatings.

20. The test device of claim 15, wherein the intermediate layer is permeable or impermeable.

21. The testing device of claim 1, wherein the intermediate layer comprises polyethylene terephthalate (PET).

22. The testing device of claim 1, wherein the inlet layer comprises polyethylene terephthalate (PET).

23. The test device of claim 1, wherein the test stack further comprises a first bonding layer disposed between the inlet layer and the intermediate layer, the first bonding layer bonding the intermediate layer to the inlet layer, and wherein the inlet hole further extends through the first bonding layer.

24. The test device of claim 1, wherein the test stack further comprises a support layer disposed adjacent to the sensor layer, opposite the intermediate layer, and wherein the support layer at least partially forms an exterior surface of the test stack.

25. The test device of claim 24, wherein the test stack further comprises a second bonding layer disposed between the sensor layer and the support layer, and wherein the second bonding layer bonds the support layer to the sensor layer.

26. The testing device of claim 24, wherein the support layer comprises polyethylene terephthalate (PET).

27. The testing device of claim 24, wherein the inlet layer, the intermediate layer, the sensor layer, and the support layer at least together form a laminate construction.

28. The test device of claim 24, wherein the support layer is impermeable to the steam sterilant.

29. The testing apparatus of claim 1, wherein each electrode of the at least one pair of electrodes comprises at least one of silver, carbon, and aluminum.

30. The test device of claim 1, wherein the electroactive polymer of the at least one sensor coating comprises polyaniline, trans-polyacetylene, poly(p-phenylene), poly(3-vinylperylene), polypyrrole, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene), poly(2-(3-thienyloxy)ethanesulfonate), polythiophene, or a combination thereof.

31. The testing device of claim 1, wherein the at least one sensor coating further comprises tin.

32. The testing device of claim 1, wherein the at least one sensor coating is further configured to change the electrical impedance across the at least one pair of electrodes to exceed a predetermined threshold impedance when in contact with the steam sterilant.

33. The test device of claim 1, wherein each of the inlet layer and the sensor layer is impermeable to the steam sterilant.

34. A disinfection monitoring system, comprising: The test apparatus according to claim 1; and A reader is configured to at least partially receive the test device therein for measuring electrical impedance across the at least one pair of electrodes.

35. A disinfection system, comprising: The disinfection monitoring system according to claim 34; and A sterilizer includes a chamber configured to receive the test device therein, wherein the sterilizer is configured to perform a sterilization process on the test device using a steam sterilant within the chamber.

36. A method for monitoring sterilization within a chamber using the test device of claim 1, the method comprising: disposing the testing device in the chamber; performing a sterilization process on the test device using a steam sterilizer; removing the test device from the chamber; as well as The testing device is at least partially inserted into a reader for measuring electrical impedance across the at least one pair of electrodes.

37. A test device for monitoring sterilization using a steam sterilizer in a chamber, the test device comprising: A test stack, the test stack defining a main plane and a perimeter, the test stack comprising: a top layer comprising: a first major surface, the first major surface being proximate to the chamber; a second major surface, the second major surface being opposite the first major surface; and an inlet aperture, the inlet aperture extending at least partially through the top layer from the first major surface and configured to be fluidly connected to the chamber, and in combination with at least one intermediate path, the at least one intermediate path being at least partially aligned with and configured to be fluidly connected to the inlet aperture, the at least one intermediate path defining a path length along the major plane and a path depth normal to the major plane, wherein the at least one intermediate path extends at least partially through the top layer from the second major surface along the path depth, and wherein the at least one intermediate path is spaced apart from a perimeter of the test stack; a sensor layer disposed adjacent to the second major surface of the top layer, wherein the sensor layer includes at least one pair of electrodes disposed on the sensor layer; and at least one sensor coating disposed on at least a portion of the sensor layer and comprising an electroactive polymer, wherein the at least one intermediate path of the top layer extends at least along the path length from the inlet aperture to the at least one sensor coating such that the at least one intermediate path fluidly connects the inlet aperture with the at least one sensor coating, and wherein the at least one sensor coating is electrically coupled to the at least one pair of electrodes on the sensor layer; wherein the top layer is configured to allow steam sterilant received from the inlet aperture to flow to the at least one sensor coating, and wherein the at least one sensor coating is configured to change an electrical impedance across the at least one pair of electrodes when the steam sterilant contacts the at least one sensor coating.

38. The test apparatus of claim 37, wherein the test stack further comprises a support layer disposed adjacent to the sensor layer and opposite the top layer, and wherein the support layer at least partially forms an exterior surface of the test stack.

39. The test device of claim 38, wherein the test stack further comprises a bonding layer disposed between the sensor layer and the support layer, and wherein the bonding layer bonds the support layer to the sensor layer.

40. The test device of claim 37, wherein the test stack further comprises a bonding layer disposed between the sensor layer and the top layer, and wherein the bonding layer bonds the top layer to the sensor layer.

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