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 a pair of electrodes disposed on the sensor layer. The test stack also includes a sensor coating disposed on a portion of the sensor layer and comprising an electroactive polymer. The test stack also includes a channel layer disposed between the inlet layer and the sensor layer. The channel layer includes an internal channel. The internal channel is configured to allow steam disinfectant to flow from the inlet orifice to the 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, which defines a main plane and a perimeter. The test stack includes an inlet layer, which includes 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, which is spaced apart from the inlet layer. The sensor layer includes a pair of electrodes disposed on the sensor layer. The test stack also includes a sensor coating, which is disposed on a portion of the sensor layer and contains the electroactive polymer. The sensor coating is spaced apart from the inlet hole at least along the main plane of the test stack. The sensor coating is electrically coupled to the pair of electrodes. The test stack also includes a channel layer, which is disposed between the inlet layer and the sensor layer. The channel layer includes an internal channel defining a channel length along the main plane and a channel depth normal to the main plane. The internal channel is spaced apart from the perimeter of the test stack. The internal channel extends through the channel layer along the channel depth. The internal passage extends at least along the passage length from the inlet hole to the sensor coating so that the internal passage fluidly connects the inlet hole with the sensor coating. The internal passage is configured to allow steam sterilant to flow from the inlet hole to the sensor coating. The sensor coating is configured to change the electrical impedance across the pair of electrodes when the steam sterilant contacts the 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 support configured to at least partially and removably receive the test device therein.

[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 support and 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 air removal within a chamber using the test device of the first aspect. The method includes: positioning 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 the electrical impedance across the 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 is close to the chamber; a second major surface, the second major surface is opposite to the first major surface; an inlet hole, the inlet hole extends from the first major surface at least partially through the top layer and is configured to be fluidly connected to the chamber; and an internal channel, the internal channel is at least partially aligned with the inlet hole and is configured to be fluidly connected to the inlet hole. The internal channel defines an internal channel with a channel length along the major plane and a channel depth normal to the major plane. The internal channel extends from the second major surface at least partially through the top layer along the channel depth. The internal channel is spaced apart from the perimeter of the test stack. The test stack also includes a sensor layer, the sensor layer is disposed adjacent to the second major surface of the top layer. The sensor layer includes a pair of electrodes disposed on the sensor layer. The test stack also includes a sensor coating, the sensor coating is disposed on a portion of the sensor layer and includes the electroactive polymer. The internal channel of the top layer extends at least along the channel length from the inlet hole to the sensor coating such that the internal channel fluidly connects the inlet hole with the sensor coating.The sensor coating is electrically coupled to the electrode on the sensor layer. 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 2A According to the embodiments of the present disclosure Figure 1 A top perspective view of a test device for a disinfection system;

[0012] Figure 2B is a bottom perspective view of the test apparatus of FIG. 2 according to an embodiment of the present disclosure;

[0013] Figure 3A According to an embodiment of the present disclosure, the method includes: Figure 2A The test stack is shown cut along line A-A'. Figure 2A A cross-sectional side view of a test device;

[0014] Figure 3B According to an embodiment of the present disclosure, the method includes: Figure 2A A cross-sectional front view of the test device of the test stack taken along line BB' is shown;

[0015] Figure 3C According to an embodiment of the present disclosure, the method includes: Figure 2A A cross-sectional front view of the test device of the test stack taken along line CC' shown;

[0016] Figure 4 According to the embodiments of the present disclosure Figure 3A A top view of a test stack, with some layers not shown;

[0017] Figure 5 According to the embodiments of the present disclosure Figure 3A A bottom view of a test stack with some layers not shown;

[0018] Fig. 6A According to another embodiment of the present disclosure Figure 3A A bottom view of a test stack with some layers not shown;

[0019] Figure 6B According to another embodiment of the present disclosure Figure 3A A bottom view of a test stack with some layers not shown;

[0020] Figure 7 Schematically shows an embodiment according to the present disclosure Figure 1 Reader for disinfection system;

[0021] Figure 8 is a cross-sectional side view of a test device according to another embodiment of the present disclosure;

[0022] Fig. 9 is a cross-sectional side view of a test device according to another embodiment of the present disclosure;

[0023] Fig.10 is a cross-sectional side view of a test device according to another embodiment of the present disclosure;

[0024] FIG. 11A to FIG. 11D are different views of a stent according to an embodiment of the present disclosure, the stent being configured to at least partially and removably receive Figure 2A Test equipment;

[0025] FIG. 12A to FIG. 12D are different views of a stent according to another embodiment of the present disclosure, the stent being configured to at least partially and removably receive Figure 2A Test equipment;

[0026] Fig.13A and Fig. 13BAccording to the embodiments of the present disclosure Fig. 12A Different views of the bracket, where Figure 2A The test device is at least partially received in the bracket;

[0027] Fig.14 According to the embodiments of the present disclosure, Figure 2A A flow chart of a method for monitoring sterilization of a test device within a chamber; and

[0028] Fig.15 Is in various test cycles across Figure 2A a discrete plot of the electrical impedance of a pair of electrodes of a test device; and

[0029] Fig.16 is an example of cross Figure 2A A graph of the probability density function of the logarithmic value of the electrical impedance of a pair of electrodes of the test device. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The present disclosure relates to a test device for monitoring the steam quality of a steam sterilant in a chamber. The test device includes a test stack, which defines a main plane and a periphery. The test stack includes an inlet layer, which includes 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, which is spaced apart from the inlet layer. The sensor layer includes a pair of electrodes disposed on the sensor layer. The test stack also includes a sensor coating, which is disposed on a portion of the sensor layer and contains the electroactive polymer. The sensor coating is spaced apart from the inlet hole at least along the main plane of the test stack. The sensor coating is electrically coupled to the pair of electrodes. The test stack also includes a channel layer, which is disposed between the inlet layer and the sensor layer. The channel layer includes an internal channel defining a channel length along the main plane and a channel depth normal to the main plane. The internal channel is spaced apart from the periphery of the test stack. The internal channel extends through the channel layer along the channel depth. The internal channel extends from the inlet hole to the sensor coating at least along the channel length, so that the internal channel connects the inlet hole to the sensor coating fluid. The internal channel is configured to allow steam sterilant to flow from the inlet hole to the sensor coating. The sensor coating is configured to change the electrical impedance across the pair of electrodes when the steam sterilant contacts the sensor coating. In an embodiment, the internal channel is at least partially non-linear along the channel length.

[0035] 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.

[0036] In order to monitor the sterilization using steam sterilizer, the test device is placed in the chamber of the sterilizer and the sterilization process begins. Since the internal passage connects the inlet hole to the sensor coating fluid, and the inlet hole is connected to the chamber fluid, the chamber is indirectly connected to the sensor coating fluid. In the case of any non-condensable gas or air in the chamber, the air may contact the sensor coating via the internal passage, and this prevents the steam sterilizer from making any contact with the sensor coating. Therefore, in the real-time sterilization process, in the presence of air, the steam sterilizer may not reach the hollow space and internal cavity of the medical equipment being sterilized. In the absence of non-condensable gas or air in the chamber, the steam sterilizer may be able to contact the sensor coating via the internal passage. Therefore, in the absence of air, the steam sterilizer can reach the hollow space and internal cavity of the medical equipment being sterilized. In other words, in order to make the quality of the steam sterilizer acceptable, there should not be any air in the chamber of the sterilizer.

[0037] Since the internal channel can be at least partially nonlinear along the channel length, the internal channel can provide a considerable channel resistance to the flow of steam sterilant through the internal channel. Specifically, the internal channel can provide a channel resistance corresponding to the resistance provided by the different routes and channels, and in the real-time sterilization process, the steam sterilant must follow these routes and channels to reach the hollow space and internal cavity of the medical equipment. Therefore, the channel resistance provided by the internal channel can represent the resistance of various flow channels leading to the hidden space of the tube, catheter, syringe needle, etc. The channel resistance to the flow of steam sterilant provided by the internal channel can depend on the shape and size of the internal channel. In addition, the shape and size of the internal channel can vary based on different application attributes.

[0038] In addition, the sensor coating is further configured to change the electrical impedance across the 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 sensor coating, the electrical impedance across the pair of electrodes exceeds the predetermined threshold impedance. In addition, in the presence of air in the internal passage, the steam sterilant may not be in contact with the sensor coating, and the electrical impedance across the 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 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 channel layer of the test device at least partially define a cutout disposed at the periphery of the test stack. Each electrode in the 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 pair of electrodes. The magnitude of the electrical impedance across the 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 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 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 a predetermined threshold impedance and the electrical impedance across the pair of electrodes.

[0040] In the case where the electrical impedance across the pair of electrodes exceeds the 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 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 otherwise may 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 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] The disinfection monitoring system of the present disclosure also includes a bracket, which is configured to at least partially and removably receive the test device therein. The bracket is further configured to removably fix or retain the test device. In order to perform a disinfection monitoring cycle, the bracket and the test device at least partially received in the bracket are placed in a chamber of the disinfector. The bracket can maintain the position of the test device unchanged during the disinfection phase in the disinfector. The bracket is designed so that it allows fluid connection between the chamber of the disinfector and the test device. In addition, the bracket can have sufficient weight to removably fix the test device therein. The bracket is made of such a material that the bracket is mechanically stable during the disinfection cycle and thus limits the mechanical movement of the test device during the disinfection cycle.

[0044] During the sterilization monitoring cycle, the support can prevent any deformation or expansion of any layer of the test device. In addition, the support can also prevent delamination of the test device, which may otherwise cause erroneous test results of the steam quality of the steam sterilant. Therefore, the sterilization monitoring system including the support and the test device received in the support can improve the accuracy of the test results.

[0045] Since the holder is configured to removably secure the test device therein, the robustness of the test device may be reduced, which may further result in a reduction in the manufacturing cost of the test device. In some cases, the holder is manufactured as a single-piece component comprising a plastic material. In addition, the holder may be reused several times for multiple sterilization monitoring cycles.

[0046] The sterilization monitoring system including the test device and the bracket can also be used for other sterilization methods, such as vaporized hydrogen peroxide sterilization. In addition, the sterilization monitoring system can be used in different types of steam sterilizers that have been manufactured and are currently being used in the medical industry.

[0047] 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.

[0048] 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 sterilization monitoring system 106 also includes a rack 308 that is configured to at least partially and removably receive the test device 110 therein. The chamber 104 is configured to receive the rack 308 and the test device 110 therein. The sterilizer 102 is configured to perform a sterilization process on the test device 110 using the steam sterilizer within the chamber 104. The rack 308 will be described later in the description.

[0049] Figure 2A is a top perspective view of a test apparatus 110 according to an embodiment of the present disclosure. Figure 2B1 is a bottom 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.

[0050] Figure 3A According to an embodiment of the present disclosure, the method includes: Figure 1 The cross-sectional side view of the test device 110 of the test stack 112 is shown along the line AA'. The line AA' is zigzag along the xy plane. More specifically, Figure 3A is a cross-sectional side view of the test device 110 when viewed from the side 105 of the test device 110 . Figure 3B According to an embodiment of the present disclosure, the method includes: Figure 2A A cross-sectional front view of the test apparatus 110 of the test stack 112 is shown taken along line BB′. Figure 3C According to an embodiment of the present disclosure, the method includes: Figure 2A A cross-sectional front view of the test apparatus 110 of the test stack 112 is shown taken along line CC′.

[0051] refer to FIG. 3A to FIG. 3C , 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 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 inlet layer 202 defines a thickness T1 along the z-axis. In some cases, the thickness T1 of the inlet layer is about 0.01 inches.

[0052] The inlet hole 204 and the chamber 104 (such as Figure 1 ) fluid connections. Figure 3A In the illustrated embodiment, the inlet hole 204 is circular and thus has a diameter d1 and a radius r1 (d1 / 2). 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.

[0053] 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 embodiments, the thickness T2 of the sensor layer 206 is about 0.003 inches. 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.

[0054] The test stack 112 also includes a channel layer 208, which is disposed between the inlet layer 202 and the sensor layer 206. The channel layer 208 defines a thickness T3 along the z-axis. In some embodiments, the thickness T3 of the channel layer 208 is about 0.003 inches. In some embodiments, the thickness T3 of the channel layer 208 is about 10% to about 50% of the thickness T1 of the inlet layer 202. In some embodiments, the channel layer 208 comprises PET. In addition, in some other embodiments, the channel layer 208 may be made of a metal layer such as aluminum foil, a polymer layer such as polyurethane, or a polyester layer without any limitation. In addition, each of the inlet layer 202, the channel layer 208, and the sensor layer 206 is impermeable to the steam sterilizer. Therefore, each of the inlet layer 202, the channel layer 208, and the sensor layer 206 may not allow fluid (e.g., steam) to pass through.

[0055] The test stack 112 also includes a first bonding layer 210, which is disposed between the inlet layer 202 and the channel layer 208. The first bonding layer 210 bonds the channel layer 208 to the inlet layer 202. In an example, the first bonding layer 210 may include a very high adhesive, such as a pressure-sensitive adhesive, for example but not limited to silicone polyurea (SPU), acrylic, silicone, or rubber-based adhesive. In another example, the very high adhesive may include a structural adhesive, such as acrylic, cyanoacrylate, epoxy, polyurethane, or a mixture thereof. The first bonding layer 210 defines a thickness T4 along the z-axis. In some cases, the thickness T4 of the first bonding layer 210 is about 0.002 inches. In some embodiments, the thickness T4 of the first bonding layer 210 is less than the thickness T3 of the channel layer 208.

[0056] The test stack 112 also includes a second bonding layer 212 disposed between the channel layer 208 and the sensor layer 206. The second bonding layer 212 bonds the channel layer 208 to the sensor layer 206. The second bonding layer 212 defines a thickness T5 that is substantially equal to the thickness T4 of the first bonding layer 210. In addition, the second bonding layer 212 may also include a very high adhesive.

[0057] The test stack 112 further includes a patterned layer 214 disposed adjacent to the inlet layer 202 and opposite the channel layer 208. The patterned layer 214 at least partially forms an outer surface S1 of the test stack 112. The inlet hole 204 further extends through the patterned layer 214.

[0058] In some embodiments, the graphics layer 214 may include a plurality of marks (not shown) printed thereon, such as, but not limited to, letters, symbols, graphics, pictures, logos, art, company information, icons, etc. The plurality of marks may be associated with and / or represent a business, company, or organization, etc., or a product, service, etc., or both. In some examples, the graphics layer 214 may also include a code printed thereon, such as a radio frequency identification (RFID) tag, a bar code, etc. Specifically, the plurality of marks on the graphics layer 214 may display information related to a date, a serial number, product specifications, a company logo, or a mark of use of the test device 110.

[0059] The test stack 112 further includes a support layer 216 disposed adjacent to the sensor layer 206 and opposite the channel 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 pattern layer 214.

[0060] 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 T6 along the z-axis. In some cases, the thickness T6 of the support layer 216 is about 0.01 inches. In some embodiments, the thickness T6 of the support layer 216 is substantially equal to the thickness T1 of the inlet layer 202. In some embodiments, the support layer 216 is impermeable to the steam sterilizer.

[0061] In some embodiments, the inlet layer 202, the channel 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 third bonding layer 218, which is disposed between the sensor layer 206 and the support layer 216. The third bonding layer 218 bonds the support layer 216 to the sensor layer 206. The third bonding layer 218 defines a thickness T7 along the z-axis. In some embodiments, the third bonding layer 218 may have a thickness of about 0.002 inches. In some embodiments, the third bonding layer 218 may include a bonding agent with very high adhesion. In one example, the thickness T4 of the first bonding layer 210, the thickness T5 of the second bonding layer 212, and the thickness T7 of the third bonding layer 218 may be substantially equal to each other. In some embodiments, one or more layers of the test stack 112 may be transparent.

[0062] Figure 4 A top view of a test stack 112 is illustrated, wherein some layers are not shown, according to an embodiment of the present disclosure. Specifically, the graphic layer 214, the inlet layer 202, and the first bonding layer 210 are not shown. Figure 4 The test stack 112 is shown in FIG. 2. The channel layer 208 includes a channel length L1 ( Figure 5 ) and the channel depth H1 normal to the main plane A1 ( Figure 3A 1 . The internal channel 220 is spaced apart from the perimeter P of the test stack 112. The internal channel 220 extends through the channel layer 208 along the channel depth H1. The internal channel 220 further extends through each of the first bonding layer 210 and the second bonding layer 212 along the channel depth H1. Specifically, the channel depth H1 extends through the thickness T4 of the first bonding layer 210, the thickness T3 of the channel layer 208, and the thickness T5 of the second bonding layer 212. In some embodiments, the channel depth H1 is about 0.006 inches to about 0.008 inches.

[0063] Figure 5 FIG. 1 is a bottom view of a test stack 112 according to an embodiment of the present disclosure, wherein some layers are not shown. Specifically, the support layer 216 and the third bonding layer 218 are Figure 5 The test stack 112 is not shown. The test stack 112 also includes a sensor coating 222 disposed on a portion of the sensor layer 206. The sensor coating 222 includes an electroactive polymer. The sensor coating 222 is at least along the main plane A1 ( Figure 2A 2 (shown in FIG. 1 ) is spaced from the inlet aperture 204. Thus, the sensor coating 222 is spaced from the inlet aperture 204 at least along the xy plane of the test device 110.

[0064] In some embodiments, the electroactive polymer of the sensor coating 222 may include 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.

[0065] 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.

[0066] In some embodiments, the sensor coating 222 further comprises tin. In some cases, the sensor coating 222 may comprise tin nanoparticles. In some other cases, the sensor coating 222 may comprise blended nanoparticles of PANI and aluminum, copper, silver, gold, or a combination thereof.

[0067] refer to Figure 4 and Figure 5 , the internal channel 220 extends from the inlet hole 204 to the sensor coating 222 at least along the channel length L1, so that the internal channel 220 fluidly connects the inlet hole 204 with the sensor coating 222. Therefore, the internal channel 220 is configured to allow the steam sterilant to flow from the inlet hole 204 to the sensor coating 222. In addition, the internal channel 220 is configured to allow non-condensable gas (e.g., air) to flow from the inlet hole 204 to the sensor coating 222.

[0068] In some cases, the inlet aperture 204 regulates the flow rate of the non-condensable gas and / or steam sterilant into and out of the interior passage 220. The flow rate is calculated according to Equation 1 provided below: Wherein, r1 is the radius of the inlet hole 204 .

[0069] In some embodiments, the radius r1 of the inlet hole 204 can vary from about 0.05 mm to 8 mm.

[0070] In some embodiments, the internal passage 220 includes a first end portion 224 that is configured to be fluidly connected to the inlet hole 204. Thus, the steam sterilant can be introduced into the chamber 104 ( Figure 1 2 (shown in FIG. 2 ) flows to a first end portion 224 of the internal passage 220. The first end portion 224 is at least partially aligned with the inlet hole 204. Specifically, the first end portion 224 is at least partially aligned with the inlet hole in the xy plane. Figure 4 and Figure 5 In the illustrated embodiment, the first end portion 224 is circular. In other embodiments, the first end portion 224 can be any other desired shape, such as a triangle, rectangle, oval, ellipse, polygon, or the like, without limitation. The first end portion 224 has a diameter D2. In some embodiments, the diameter D2 of the first end portion 224 is at least 2 times the diameter d1 of the inlet hole 204. The first end portion 224 has a width W1 extending perpendicular to the channel depth H1. Figure 4 and Figure 5 In the illustrated embodiment, the width W1 of the first end portion 224 is the same as the diameter D2 of the first end portion 224 .

[0071] In some embodiments, the internal passage 220 further includes a second end portion 226 that is spaced apart from the first end portion 224 and is configured to be fluidly connected to the sensor coating 222. Thus, the steam sterilant can flow from the second end portion 226 to the sensor coating 222. The second end portion 226 is at least partially aligned with the sensor coating 222. Specifically, the second end portion 226 is at least partially aligned with the sensor coating 222 in the xy plane. Figure 4 and Figure 5 In the illustrated embodiment, the second end portion 226 is substantially rectangular. In other embodiments, the second end portion 226 can be any other desired shape, such as a triangle, rectangle, oval, ellipse, polygon or the like, or can have rounded corners or a rounded shape. The second end portion 226 has a width W2 extending perpendicular to the channel depth H1.

[0072] In some embodiments, the internal channel 220 also includes a main portion 228 extending from the first end portion 224 to the second end portion 226 along the channel length L1. The main portion 228 is at least partially non-linear along the channel length L1. In other words, the internal channel 220 is at least partially non-linear along the channel length L1. The main portion 228 has a width W3. In some embodiments, the width W3 of the main portion 228 is less than the width W1, W2 of each of the first end portion 224 and the second end portion 226, respectively.

[0073] The main portion 228 includes: a first linear portion 230 extending from the first end portion 224; a curved portion 232 extending from the first linear portion 230; and a second linear portion 234 extending from the curved portion 232 to the second end portion 226. The first linear portion 230 has a length s1. The second linear portion 234 has a length s2. Figure 4 and Figure 5 In the illustrated embodiment, the length s1 of the first linear portion 230 is at least twice the length s2 of the second linear portion 234. In addition, the first linear portion 230, the curved portion 232, and the second linear portion 234 collectively define a majority of the channel length L1 of the internal channel 220.

[0074] like Figure 4 and Figure 5 As shown, the main portion 228 includes two bends in total, namely, one bend between the first linear portion 230 and the bend 232, and another bend between the bend 232 and the second linear portion 234. In some other embodiments, the main portion 228 may include more than two bends in total. Fig. 6AA bottom view of a test stack 112 according to another embodiment of the present disclosure is illustrated. In this embodiment, a main portion 228 of the internal channel 220 has a serpentine shape including a plurality of bends. As the number of the plurality of bends in the internal channel 220 increases, the channel resistance provided by the internal channel 220 to the flow of steam sterilant through the internal channel also increases. The channel resistance may depend on the shape and size of the internal channel 220. In addition, the shape and size of the internal channel 220 may vary based on different application attributes.

[0075] The relationship between the size of the second end portion 226, the channel length L1, and the radius of the main portion 228 can be expressed as the diffusion rate or proportional diffusion length of the internal channel 220. The diffusion rate is calculated according to Equation 2 provided below: Among them, L D is the diffusion rate of the internal channel 220; D is the diffusion constant of air during the air removal phase of the sterilization cycle, or the diffusion constant of the steam sterilant during the exposure phase of the sterilization cycle; r h is the radius of the main portion 228; µ is the air viscosity (during the air removal phase of the sterilization cycle) or the steam sterilant viscosity (during the exposure phase of the sterilization cycle); ΔP is the pressure difference across the internal passage 220; L is the effective length of the internal channel 220 (the effective length of the internal channel 220 represents the channel length L1 plus the volume of the second end portion 226 and the radius r of the main portion 228). h proportional additional length); and t is the time it takes for air or steam sterilant to flow through the internal passage 220.

[0076] In some embodiments, the diffusion rate L D The value of can be in the range of about 0.02 cm to 60 cm.

[0077] Figure 6B A bottom view of a test stack 112 according to yet another embodiment of the present disclosure is illustrated. In this embodiment, a main portion 228 of an internal channel 220 has a rectangular shape including two bends. Specifically, the main portion 228 does not include any bends. The two bends form a nonlinear portion of the internal channel 220.

[0078] refer to Figures 1 to 6B, in order to monitor sterilization using a steam sterilizer, the test device 110 is placed in the chamber 104 of the sterilizer 102 and the sterilization process begins. Since the internal passage 220 fluidly connects the inlet hole 204 with the sensor coating 222, and the inlet hole 204 is fluidly connected to the chamber 104, the chamber 104 is indirectly fluidly connected to the sensor coating 222. In some embodiments, any non-condensable gas or air present in the chamber 104 may contact the sensor coating 222 via the internal passage 220, and thus prevent the steam sterilizer from making any contact with the sensor coating 222. Therefore, during the real-time sterilization process, in the presence of air, the steam sterilizer may not reach the hollow space and internal cavity of the medical equipment being sterilized. In the absence of non-condensable gas or air in the chamber 104, the steam sterilizer may be able to contact the sensor coating 222 via the internal passage 220. Therefore, in the absence of air, the steam sterilizer can reach the hollow space and internal cavity of the medical equipment being sterilized. In other words, in order for the quality of the steam sterilant to be acceptable, there should not be any air present within the chamber 104 of the sterilizer 102 .

[0079] Since the internal channel 220 is at least partially nonlinear along the channel length L1, the internal channel 220 can provide a considerable channel resistance to the flow of the steam sterilant through the internal channel 220. Specifically, the internal channel 220, which is at least partially nonlinear, can provide a channel resistance that corresponds to the resistance provided by the different routes and channels that the steam sterilant must follow to reach the hollow space and internal cavity of the medical equipment during the real-time sterilization process. Therefore, the channel resistance provided by the internal channel 220 can represent the resistance of various flow channels leading to the hidden space of the tube, catheter, syringe needle, etc.

[0080] refer to Figures 1 to 5 , the sensor layer 206 includes a pair of electrodes 236 disposed on the sensor layer 206. In addition, the sensor coating 222 is electrically coupled to the pair of electrodes 236. Each electrode in the pair of electrodes 236 may include a conductive material. In some embodiments, each electrode in the pair of electrodes 236 includes at least one of silver, carbon, and aluminum.

[0081] In some embodiments, at least a portion of each electrode of the pair of electrodes 236 is disposed between the sensor coating 222 and the sensor layer 206 such that a gap G1 is defined between the pair of electrodes 236. The gap G1 is covered by the sensor coating 222. The second end portion 226 of the internal channel 220 surrounds at least a portion of each electrode of the pair of electrodes 236 and the gap G1 between the pair of electrodes 236.

[0082] In some embodiments, the inlet layer 202 and the channel layer 208 at least partially define a cutout C1 disposed at the perimeter P of the test stack 112. Each electrode of the pair of electrodes 236 extends at least partially into the cutout C1. Each electrode of the pair of electrodes 236 includes: a first rectangular portion 238 electrically coupled to the sensor coating 222; a second rectangular portion 240 disposed within the cutout C1; and a narrow elongated portion 242 connecting the first rectangular portion 238 to the second rectangular portion 240.

[0083] The disinfection monitoring system 106 also includes a reader 114 ( Figure 1 ), the reader being configured to at least partially receive therein a test device 110 for measuring an electrical impedance I1 across the pair of electrodes 236. Figure 7 The reader 114 according to an embodiment of the present disclosure is schematically shown. Figure 7 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.

[0084] refer to Figures 1 to 7 , 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 pair of electrodes 236. In addition, the sensor coating 222 is configured to change the electrical impedance I1 across the pair of electrodes 236 when the steam sterilant contacts the sensor coating 222. In some embodiments, the sensor coating 222 is configured to change the electrical impedance I1 across the pair of electrodes 236 to exceed a predetermined threshold impedance I2 (which may be stored in the memory 116) when in contact with the steam sterilant.

[0085] In addition, it should be noted that the electroactive polymer in the 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 pair of electrodes 236 can be coated with or formed of a conductive material such as silver or aluminum, the conductive material can directly react with the 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 pair of electrodes 236 under the ambient conditions of the chamber 104, the sensor coating 222 can be transformed from one impedance state to another impedance state.

[0086] Furthermore, in some embodiments, upon appropriate exposure of the steam sterilant to the sensor coating 222, the pair of electrodes 236 can switch from an electrically shorted state (ie, a small impedance between the pair of electrodes 236) to an electrically open state (ie, a large impedance between the pair of electrodes 236).

[0087] While monitoring the sterilization, once it is determined that the electrical impedance I1 across the 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 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 the comparison between the predetermined threshold impedance I2 and the electrical impedance I1 across the pair of electrodes 236.

[0088] In the case where the electrical impedance I1 across the pair of electrodes 236 exceeds the predetermined threshold impedance I2, the operator can 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 pair of electrodes 236 does not exceed the predetermined threshold impedance I2, the operator can 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.

[0089] 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 the 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.

[0090] 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.

[0091] Figure 8 is a cross-sectional side view of a test device 111 according to another embodiment of the present disclosure. The cross-sectional side view of the test device 111 is taken along Figure 2A The test device 111 is substantially similar to Figure 3A 10, wherein common components are indicated by the same reference numerals. However, the test device 111 also includes a porous membrane 118, which is disposed on the test stack 112 and covers the inlet hole 204. The porosity of the porous membrane 118 allows a fluid connection between the chamber 104 and the inlet hole 204. Specifically, the porous membrane 118 allows the steam sterilant to flow from the chamber 104 to the inlet hole 204, and then to the sensor coating 222 via the internal channel 220. In some embodiments, the inclusion of the porous membrane 118 can increase the overall resistance provided by the test device 111 to the flow of the steam sterilant.

[0092] Fig. 9 is a cross-sectional view of a test device 113 according to another embodiment of the present disclosure. The cross-sectional side view of the test device 113 is taken along Figure 2A The test device 113 is substantially similar to Figure 3A 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 3A1 , wherein common components are denoted by the same reference numerals. However, in the test stack 112', no adhesive layer bonds the inlet layer 202 to the channel layer 208. Furthermore, no adhesive layer bonds the channel layer 208 to the sensor layer 206. Furthermore, no adhesive layer bonds the sensor layer 206 to the support layer 216. Thus, the test stack 112' does not have any separate adhesive layer. Fig. 9 In the illustrated embodiment, each adjacent layer of the test stack 112' can be welded, laminated, or ultrasonically bonded to each other. For example, the channel layer 208 can be ultrasonically bonded to the sensor layer 206. For example, the sensor layer 206 can be welded to the support layer 216.

[0093] Fig.10 is a cross-sectional view of a test device 115 according to another embodiment of the present disclosure. The cross-sectional side view of the test device 115 is taken along Figure 2A The test device 115 is substantially similar to Figure 3A The test device 110 is illustrated in FIG. 1 , wherein common components are denoted by the same reference numerals. In addition, the test device 115 includes a substantially similar Figure 3A 1 , a test stack 112 ″ of a test device 110 is illustrated in FIG. 1 , wherein common components are denoted by the same reference numerals.

[0094] However, the test stack 112 ″ includes a top layer 152 (instead of Figure 3A 104 and 106 ), the top layer including a first major surface 154 proximate to the chamber 104 and a second major surface 156 opposite to the first major surface 154. The top layer 152 also includes an inlet hole 204 that extends from the first major surface 154 at least partially through the top layer 152 and is configured to be fluidically connected to the chamber 104. The top layer 152 also includes an internal channel 220 that is at least partially aligned with the inlet hole 204 and is configured to be fluidically connected to the inlet hole. Specifically, the internal channel 220 is at least partially aligned with the inlet hole 204 in the xy plane. The internal channel 220 extends from the second major surface 156 at least partially through the top layer 152 along the channel depth H1.

[0095] In addition, the sensor layer 206 is disposed adjacent to the second major surface 156 of the top layer 152. In addition, the sensor coating 222 is electrically coupled to the pair of electrodes 236 ( Figure 4 ). Therefore, Fig.10 The test equipment 115 and Figure 3A The main difference between the test device 110 and the test device 115 is that the test device 115 includes a top layer 152, which is Figure 3AThe combination of the inlet layer 202 and the channel layer 208 is illustrated in FIG.

[0096] FIG. 11A to FIG. 11D are different views of a bracket 308 configured to at least partially and removably receive a test device 110 (in accordance with an embodiment of the present disclosure) Figures 2A to 3C ).

[0097] The bracket 308 includes a first open end 344 configured to receive the test device 110 at least partially therethrough. The bracket 308 also includes a second open end 346 opposite the first open end 344. The bracket 308 includes a first portion 348 extending from the first open end 344 to the second open end 346. The bracket 308 also includes a second portion 350 opposite the first portion 348 and extending from the first open end 344 to the second open end 346. The bracket 308 also includes a pair of lateral portions 360 disposed opposite each other and connecting the first portion 348 to the second portion 350. The first portion 348, the second portion 350, and the pair of lateral portions 360 together define a volume V1 therebetween. The volume V1 extends from the first open end 344 to the second open end 346 and is configured to at least partially and removably receive the test device 110 therein. The bracket 308 also defines a transverse axis TA extending between the pair of lateral portions 360 .

[0098] The bracket 308 also includes a plurality of first ribs 362 that are spaced apart from each other and extend from the first portion 348 to the second portion 350. Each of the plurality of first ribs 362 extends at least partially between the first open end 344 and the second open end 346. The bracket 308 also includes a plurality of second ribs 364 that are spaced apart from each other and extend from the second portion 350 to the first portion 348. Each of the plurality of second ribs 364 extends at least partially between the first open end 344 and the second open end 346. The plurality of first ribs 362 and the plurality of second ribs 364 are configured to at least partially engage the test device 110 and removably secure the test device 110 therebetween. The bracket 308 also includes a wall 307 that surrounds each of the plurality of first ribs 362 and the plurality of second ribs 364. In some examples, the wall 307 may have a thickness of about 3 millimeters (mm) to 4 mm.

[0099] In some embodiments, the plurality of first ribs 362 and the plurality of second ribs 364 define a support gap G2 therebetween. The support gap G2 is a portion of the volume V1 that at least partially and removably receives the test device 110 therein. In some embodiments, the height of the support gap G2 is about 0.03 inches to 0.075 inches. In some embodiments, the height of the support gap G2 is about the thickness T ( Fig. 13B The support gap G2 allows the test device 110 to be received and expanded during the sterilization monitoring cycle in the chamber 104.

[0100] In some embodiments, any two adjacent first ribs 362 from the plurality of first ribs 362 or any two adjacent second ribs 364 from the plurality of second ribs 364 define a spacing P1 therebetween. In some embodiments, the spacing P1 is about 5 mm to 10 mm. In addition, in some embodiments, the width B1 of each first rib in the plurality of first ribs 362 and each second rib in the plurality of second ribs 364 is about 1 mm to 4 mm.

[0101] exist FIG. 11A to FIG. 11D In the illustrated embodiment, the plurality of first ribs 362 and the plurality of second ribs 364 are disposed in a staggered configuration relative to each other such that at least one of the plurality of first ribs 362 is disposed between a pair of adjacent second ribs 364 from the plurality of second ribs 364 relative to a transverse axis TA extending between the pair of lateral portions 360. In addition, at least one of the plurality of second ribs 364 is disposed between a pair of adjacent first ribs 362 from the plurality of first ribs 362 relative to the transverse axis TA.

[0102] exist FIG. 11A to FIG. 11D In the illustrated embodiment, the first portion 348 includes a plurality of first elongated members 352 that are spaced apart from one another and define a plurality of first slots 354 therebetween. The second portion 350 includes a plurality of second elongated members 356 that are spaced apart from one another and define a plurality of second slots 358 therebetween. Each of the plurality of first elongated members 352 and each of the plurality of second elongated members 356 extend between the first open end 344 and the second open end 346. The plurality of first slots 354 and / or the plurality of second slots 358 are configured to allow fluid connection between the chamber 104 and the inlet aperture 204 of the test device 110.

[0103] exist FIG. 11A to FIG. 11DIn the illustrated embodiment, the plurality of first elongated members 352 and the plurality of second elongated members 356 are disposed in a staggered configuration relative to one another such that at least one of the plurality of first elongated members 352 is disposed between a pair of adjacent second elongated members 356 from the plurality of second elongated members 356 relative to the transverse axis TA extending between the pair of lateral portions 360. Additionally, at least one of the plurality of second elongated members 356 is disposed between a pair of adjacent first elongated members 352 from the plurality of first elongated members 352 relative to the transverse axis TA.

[0104] In some embodiments, the bracket 308 also includes a plurality of stop ribs 366 disposed at the second open end 346 and extending between the first portion 348 and the second portion 350. The plurality of stop ribs 366 are configured to at least partially engage the test device 110, thereby preventing the test device 110 from being removed from the bracket 308 through the second open end 346.

[0105] In some embodiments, the bracket 308 can be manufactured via a manufacturing process, such as, but not limited to, an additive manufacturing process, a molding process, etc. In some cases, the bracket 308 can be made of various materials, such as, but not limited to, nylon or any other material. In some embodiments, the bracket 308 is made of a material including aluminum, steel, machinable and 3D printable metals and metal alloys, polyphenylsulfone, polyethersulfone, polyetherimide, polyetherimide sulfone, and combinations thereof.

[0106] In some embodiments, the bracket 308 can be made by machining metal via a turning process, a grinding process, a milling process, a drilling process, or a combination thereof. In some other embodiments, the bracket 308 can be made by a 3D printing method (such as stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), digital light processing (DLP), multi-jet melting (MJF), polyjet, direct metal laser sintering (DMLS), electron beam melting, etc.) using a thermally stable 3D printable resin material (such as acrylonitrile butadiene styrene (ABS), thermoplastic polyurethane (TPU), composite materials, etc.).

[0107] FIG. 12A to FIG. 12D is a different view of a bracket 408 according to another embodiment of the present disclosure, the bracket being configured to at least partially and removably receive a test device 110 (in Figures 2A to 3C ). Bracket 408 is functionally equivalent to FIG. 11A to FIG. 11D 308, wherein common components are denoted by the same reference numerals. However, in the bracket 408, at least one of the first portion 348 and the second portion 350 has a substantially continuous planar shape without an opening. FIG. 12A to FIG. 12D In the illustrated embodiment, each of the first portion 348 and the second portion 350 has a substantially continuous planar shape without an opening. Therefore, in the bracket 408, each of the first portion 348 and the second portion 350 does not include any elongated member (such as FIG. 11A to FIG. 11D 352 and the second elongated member 356).

[0108] In addition, the bracket 408 does not include any stop ribs (such as FIG. 11A to FIG. 11D 366 in the bracket 408). However, the bracket 408 includes a plurality of first stop protrusions 368 extending from the plurality of first ribs 362 at the second open end 346 and extending toward the second portion 350. The bracket 408 also includes a plurality of second stop protrusions 370 extending from the plurality of second ribs 364 at the second open end 346 and extending toward the first portion 348. The plurality of first stop protrusions 368 and the plurality of second stop protrusions 370 are configured to at least partially engage the test device 110, thereby preventing the test device 110 from being removed from the bracket 408 through the second open end 346.

[0109] Bracket 408 is designed such that it allows fluid connection between chamber 104 of sterilizer 102 and test device 110. In some cases, at least one of first open end 344 and second open end 346 allows fluid connection between chamber 104 and test device 110.

[0110] Fig.13A and Fig. 13B 408 according to an embodiment of the present disclosure, wherein the test device 110 ( Figure 2A and Figure 2B ) is at least partially received in the bracket 408. It should be noted that the bracket 308 ( Fig.11A ) is also constructed to Fig.13A and Fig. 13B The test device 110 is at least partially received in a similar manner as shown.

[0111] refer to Figure 1 and FIG. 11A to FIG. 13BTo perform a sterilization monitoring cycle, the rack 408 (or any of the racks 308, 408) and the test device 110 at least partially received in the rack 408 are placed in the chamber 104 of the sterilizer 102. The rack 408 can maintain the position of the test device 110 during the sterilization phase in the sterilizer 102. Therefore, the rack 408 can prevent any deformation or expansion of any layer of the test device 110 during the sterilization monitoring cycle. In addition, the rack 408 can also prevent delamination of the test device 110, which can otherwise cause erroneous test results of the steam quality of the steam sterilizer. Therefore, the sterilization monitoring system 106 including the rack 408 and the test device 110 received in the rack 408 can improve the accuracy of the test results.

[0112] In addition, the bracket 408 can have sufficient weight to removably secure the test device 110 therein. The material of the bracket 408 is selected so that the bracket is mechanically stable during the sterilization cycle and thus limits the mechanical movement of the test device 110 during the sterilization cycle. In other words, the bracket 408 is selected so that the bracket can resist being forced apart due to deformation of the test device 110 caused by various test cycles used to monitor sterilization. In some embodiments, the bracket 408 is made of a material having a minimum flexural modulus of 100 kpsi. In some embodiments, the bracket 408 is made of a material having a flexural modulus in the range of 300 kpsi to 450 kpsi. In some cases, the flexural modulus in this specific range can help secure the test device 110 within the bracket 408 and prevent delamination due to various test cycles used to monitor sterilization.

[0113] In some embodiments, because the bracket 408 is configured to removably secure the test device 110 therein, the robustness of the test device 110 may be reduced, which may further result in a reduced manufacturing cost of the test device 110. In some cases, the bracket 408 is manufactured as a single piece comprising a plastic material. In addition, the bracket 408 may be reused several times for multiple sterilization monitoring cycles. Fig.11A The functional advantages of bracket 408 are substantially the same as those of bracket 408.

[0114] The sterilization monitoring system 106 including the test device 110 and the bracket 408 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.

[0115] Fig.14 An example of a method for using the test device 110 ( Figure 2A 104 ) to monitor the air removal in the chamber 104. Figures 1 to 10 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. Example Example 1

[0116] Various test cycles are performed to check / verify a pair of electrodes 236 ( Figure 2A The electrical impedance value is shown in Figure 1. Fig.15 6 is a discrete graph 600 of the electrical impedance I1 across the pair of electrodes 236 of the test device 110 in various test cycles. Specifically, in one of the experiments, six test cycles were performed. The electrical impedance I1 is plotted in megohms (Mohm) on the ordinate. The six test cycles are plotted on the abscissa.

[0117] The configuration of the test device 110 in the first test cycle E1 is the same as that in the fourth test cycle E4. The configuration of the test device 110 in the second test cycle E2 is the same as that in the fifth test cycle E5, but different from that in the first test cycle E1. The configuration of the test device 110 in the third test cycle E3 is the same as that in the sixth test cycle E6, but different from that in the first test cycle E1 and the second test cycle E2. The configuration of the test device 110 is based on various parameters, such as the material of the pair of electrodes 236, the composition of the sensor coating 222 ( Figure 5 ), the thickness of each layer of the test device 110, the diameter d1 of the entrance hole 204, the channel length L1, the channel depth H1, etc.

[0118] In addition, for each of the first test cycle E1, the second test cycle E2, and the third test cycle E3, the Bowie-Dick test result is classified as a failed result. In addition, for each of the fourth test cycle E4, the fifth test cycle E5, and the sixth test cycle E6, the Bowie-Dick test result is classified as a passed result. For each test cycle, the chamber 104 ( Figure 1 The temperature of the PCB (shown in FIG. 1 ) was maintained at approximately 134° C. In addition, for each test cycle, the predetermined threshold impedance I2 was estimated / set to approximately 60 Mohm.

[0119] Referring to the drawing 600, it is apparent that the electrical impedance I1 in each of the first test cycle E1, the second test cycle E2, and the third test cycle E3 is much lower than (i.e., does not exceed) the predetermined threshold impedance I2 (i.e., 60 Mohm). In other words, in all test cycles corresponding to the failed Bowie-Dick test results, the electrical impedance I1 is lower than the predetermined threshold impedance I2. In addition, it is apparent that the electrical impedance I1 in each of the fourth test cycle E4, the fifth test cycle E5, and the sixth test cycle E6 exceeds the predetermined threshold impedance I2 (i.e., 60 Mohm). In other words, in all test cycles corresponding to the passed Bowie-Dick test results, the electrical impedance I1 exceeds the predetermined threshold impedance I2.

[0120] Therefore, it can be concluded from plot 600 that all three configurations of test device 110 provide accurate electrical impedance values ​​corresponding to passing and / or failing Bowie-Dick test results. In other words, the electrical impedance I1 corresponding to a failing Bowie-Dick test result is significantly different from the electrical impedance I1 corresponding to a passing Bowie-Dick test result. Example 2

[0121] Testing is performed to determine the pair of electrodes 236 ( Figure 2A 1 ) is a probability density function of the logarithmic value of the electrical impedance I1 of the sterilizer 102. In this test, each of the pair of electrodes 236 contains at least silver. Figure 1 The temperature of the precipitate (shown in FIG) was maintained at approximately 134°C. Fig.16 700 is a graph illustrating a probability density function of a logarithmic value of the electrical impedance I1 across the pair of electrodes 236 of the test device 110. The probability density function is depicted in the ordinate. The logarithmic value of the electrical impedance I1 is depicted in the abscissa. Specifically, in the case of a failed Bowie-Dick test result, the probability density function for the logarithmic value of the electrical impedance I1 is depicted by curve 702. In the case of a passed Bowie-Dick test result, the probability density function for the logarithmic value of the electrical impedance I1 is depicted by curve 704.

[0122] It is apparent from the graph 700 that the curves 702, 704 are significantly different from one another. In other words, the graph 700 depicts that the probability density function corresponding to a failed Bowie-Dick test is significantly different from the probability density function corresponding to a passed Bowie-Dick test. This separation of the curves 702, 704 can eliminate erroneous test results while monitoring sterilization in the chamber 104. In addition, from the curves 702, 704, the operator can also determine the quantitative correlation of the pass / fail results of the Bowie-Dick test performed by the test device 110.

[0123] 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.

[0124] 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 a pair of electrodes disposed on the sensor layer; a sensor coating disposed on a portion of the sensor layer and comprising an electroactive polymer, wherein the sensor coating is spaced apart from the inlet aperture along at least a major plane of the test stack, wherein the sensor coating is electrically coupled to the pair of electrodes; and a channel layer disposed between the inlet layer and the sensor layer, wherein the channel layer includes an internal channel defining a channel length along the major plane and a channel depth normal to the major plane, wherein the internal channel is spaced apart from a perimeter of the test stack, wherein the internal channel extends through the channel layer along the channel depth, wherein the internal channel extends at least along the channel length from the inlet aperture to the sensor coating such that the internal channel fluidly connects the inlet aperture with the sensor coating; Wherein the internal passage is configured to allow the steam sterilant to flow from the inlet aperture to the sensor coating, and wherein the sensor coating is configured to change an electrical impedance across the pair of electrodes when the steam sterilant contacts the sensor coating.

2. The test apparatus of claim 1, wherein the internal passageway is non-linear at least partially along the passageway length.

3. The test device of claim 2, wherein the internal passage comprises: a first end portion, the first end portion being configured to be fluidly connected to the inlet aperture; a second end portion, the second end portion being spaced apart from the first end portion and being configured to be fluidly connected to the sensor coating; and a main portion extending from the first end portion to the second end portion along the channel length, wherein the first end portion is at least partially aligned with the inlet aperture, wherein the second end portion is at least partially aligned with the sensor coating, and wherein the main portion is at least partially non-linear along the channel length. The test apparatus of claim 3 , wherein the first end portion is circular.

5. The test apparatus of claim 4, wherein the inlet aperture is circular, and wherein the diameter of the first end portion is at least 2 times the diameter of the inlet aperture.

6. The testing device of claim 3, wherein the second end portion is substantially rectangular.

7. The test device according to claim 3, wherein the main part comprises: a first linear portion extending from the first end portion; a curved portion extending from the first linear portion; and a second linear portion extending from the curved portion to the second end portion.

8. The testing device of claim 7, wherein the length of the first linear portion is at least twice the length of the second linear portion.

9. The testing device of claim 3, wherein the main portion has a serpentine shape including a plurality of bends.

10. The testing apparatus of claim 3, wherein a width of the main portion is less than a width of each of the first end portion and the second end portion.

11. A testing device according to claim 3, wherein at least a portion of each electrode in the pair of electrodes is disposed between the sensor coating and the sensor layer so that a gap is defined between the pair of electrodes, wherein the gap is covered by the sensor coating, and wherein the second end portion at least surrounds the portion of each electrode in the pair of electrodes and the gap between the pair of electrodes.

12. A test device according to claim 1, wherein the inlet layer and the channel layer at least partially define a cutout disposed at a perimeter of the test stack, wherein each electrode of the 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 pair of electrodes.

13. The testing device of claim 12, wherein each electrode of the pair of electrodes comprises: a first rectangular portion electrically coupled to the sensor coating; a second rectangular portion disposed within the cutout; and a narrow elongated portion connecting the first rectangular portion to the second rectangular portion.

14. The test device of claim 1 , wherein the test stack further comprises a graphic layer disposed adjacent to the inlet layer, opposite the channel layer, and at least partially forming an exterior surface of the test stack, and wherein the inlet hole further extends through the graphic layer.

15. The test device of claim 1, wherein the test stack further comprises: a first bonding layer, the first bonding layer being disposed between the inlet layer and the channel layer, the first bonding layer bonding the channel layer to the inlet layer; and a second bonding layer, the second bonding layer being disposed between the channel layer and the sensor layer, the second bonding layer bonding the channel layer to the sensor layer; Wherein the internal channel further extends along the channel depth through each of the first bonding layer and the second bonding layer.

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

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

18. The testing apparatus of claim 1, wherein the channel layer has a thickness of about 10% to about 50% of a thickness of the inlet layer.

19. The test apparatus of claim 1, wherein the channel layer has a thickness of approximately 0.003 inches.

20. The testing device of claim 1, wherein the sensor layer has a thickness of about 10% to about 50% of a thickness of the inlet layer.

21. The testing device of claim 1, wherein the sensor layer has a thickness of approximately 0.003 inches.

22. The testing device of claim 1, wherein the channel depth is from about 0.006 inches to about 0.008 inches.

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

24. The test device of claim 23, wherein the test stack further comprises a third bonding layer disposed between the sensor layer and the support layer, and wherein the third bonding layer bonds the support layer to the sensor layer.

25. The test device of claim 23, wherein the support layer comprises polyethylene terephthalate (PET).

26. The testing apparatus of claim 23, wherein the thickness of the support layer is substantially equal to the thickness of the inlet layer.

27. The testing device of claim 23, wherein the inlet layer, the channel layer, the sensor layer, and the support layer at least together form a laminated construction.

28. The test device of claim 23, wherein the support layer is impermeable to the steam sterilant.

29. The testing apparatus of claim 1, wherein each electrode of the 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 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 test device of claim 1, wherein the sensor coating further comprises tin.

32. The test device of claim 1, further comprising a porous membrane disposed on the test stack and covering the inlet hole.

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

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

35. A disinfection monitoring system, comprising: The test apparatus according to claim 1; and A bracket is configured to at least partially and removably receive the test device therein.

36. The disinfection monitoring system according to claim 35, wherein the support comprises: a first open end configured to receive the test device at least partially therethrough; a second open end, the second open end being opposite to the first open end; a first portion extending from the first open end to the second open end; a second portion, the second portion being opposite the first portion and extending from the first open end to the second open end; a pair of lateral portions disposed opposite one another and connecting the first portion to the second portion, wherein the first portion, the second portion, and the pair of lateral portions together define a volume therebetween, wherein the volume extends from the first open end to the second open end and is configured to at least partially and removably receive the test device therein; a plurality of first ribs spaced apart from one another and extending from the first portion to the second portion, wherein each first rib of the plurality of first ribs extends at least partially between the first open end and the second open end; and a plurality of second ribs spaced apart from one another and extending from the second portion toward the first portion, wherein each second rib of the plurality of second ribs extends at least partially between the first open end and the second open end; Wherein the plurality of first ribs and the plurality of second ribs are configured to at least partially engage the test device and removably secure the test device therebetween.

37. The disinfection monitoring system of claim 36, wherein the plurality of first ribs and the plurality of second ribs are arranged in a staggered configuration relative to each other such that: at least one first rib of the plurality of first ribs is disposed between a pair of adjacent second ribs from the plurality of second ribs relative to a transverse axis extending between the pair of lateral portions; and At least one second rib of the plurality of second ribs is disposed between a pair of adjacent first ribs from the plurality of first ribs relative to the transverse axis.

38. The disinfection monitoring system according to claim 36, wherein the support further comprises: a plurality of first stop projections extending from the plurality of first ribs at the second open end and extending toward the second portion; and a plurality of second stop projections extending from the plurality of second ribs at the second open end and extending toward the first portion; Wherein the plurality of first stop projections and the plurality of second stop projections are configured to at least partially engage the test device to prevent the test device from being removed from the bracket through the second open end.

39. The disinfection monitoring system of claim 36, wherein the plurality of first ribs and the plurality of second ribs define a support gap therebetween, and wherein the support gap is a portion of the volume for at least partially and removably receiving the test device therein.

40. The disinfection monitoring system of claim 39, wherein the height of the bracket gap is about 0.03 inches to 0.075 inches.

41. The disinfection monitoring system of claim 39, wherein the height of the bracket gap is approximately 75% to 190% of the thickness of the test device.

42. The disinfection monitoring system of claim 36, wherein any two adjacent first ribs from the plurality of first ribs or any two adjacent second ribs from the plurality of second ribs define a spacing therebetween, and wherein the spacing is approximately 5 millimeters (mm) to 10 mm.

43. The disinfection monitoring system of claim 36, wherein each of the plurality of first ribs and each of the plurality of second ribs has a width of about 1 mm to 4 mm.

44. The disinfection monitoring system of claim 36, wherein: The first portion includes a plurality of first elongated members spaced apart from one another and defining a plurality of first slots therebetween; and the second portion comprising a plurality of second elongated members spaced apart from one another and defining a plurality of second slots therebetween; wherein the plurality of first slots and / or the plurality of second slots are configured to allow fluid connection between the chamber and an inlet aperture of the testing device; wherein each first elongated member of the plurality of first elongated members and each second elongated member of the plurality of second elongated members extends between the first open end and the second open end; wherein the plurality of first elongated members and the plurality of second elongated members are arranged in a staggered configuration relative to each other such that: at least one first elongated member of the plurality of first elongated members is disposed between a pair of adjacent second elongated members from the plurality of second elongated members relative to a transverse axis extending between the pair of lateral portions; and At least one second elongated member of the plurality of second elongated members is disposed relative to the transverse axis between a pair of adjacent first elongated members from the plurality of first elongated members.

45. A disinfection monitoring system according to claim 44, wherein the bracket further includes a plurality of stop ribs, the plurality of stop ribs being disposed at the second open end and extending between the first portion and the second portion, and wherein the plurality of stop ribs are configured to at least partially engage the test device to prevent the test device from moving out of the bracket through the second open end.

46. ​​The disinfection monitoring system of claim 36, wherein at least one of the first portion and the second portion has a substantially continuous planar shape without openings.

47. The disinfection monitoring system of claim 36, wherein the support is made of a material comprising aluminum, steel, machinable and 3D printable metals and metal alloys, polyphenylsulfone, polyethersulfone, polyetherimide, polyetherimide sulfone, and combinations thereof.

48. The disinfection monitoring system of claim 36, wherein the bracket is made of a material having a minimum flexural modulus of 100 kpsi.

49. The disinfection monitoring system of claim 36, wherein the bracket is made of a material having a flexural modulus in the range of 100 kpsi to 450 kpsi.

50. The disinfection monitoring system of claim 35, further comprising a reader configured to at least partially receive the test device therein for measuring electrical impedance across the pair of electrodes.

51. A disinfection system, comprising: The disinfection monitoring system according to claim 35; and A sterilizer includes a chamber configured to receive the rack and 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.

52. A method for monitoring air removal within a chamber using the test apparatus 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 test device is at least partially inserted into a reader for measuring electrical impedance across the pair of electrodes.

53. 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, the 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; an inlet hole, the inlet hole extending at least partially through the top layer from the first major surface and configured to be fluidly connected to the chamber; and an internal channel, the internal channel at least partially aligned with the inlet hole and configured to be fluidly connected to the inlet hole, the internal channel defining a channel length along the major plane and a channel depth normal to the major plane, wherein the internal channel extends at least partially through the top layer from the second major surface along the channel depth, and wherein the internal channel 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 a pair of electrodes disposed on the sensor layer; and A sensor coating is disposed on a portion of the sensor layer and comprises an electroactive polymer, wherein the internal channel of the top layer extends at least along the channel length from the inlet hole to the sensor coating such that the internal channel fluidically connects the inlet hole with the sensor coating, and wherein the sensor coating is electrically coupled to the pair of electrodes on the sensor layer.

54. The testing device of claim 53, wherein the internal passage is configured to allow steam sterilant to flow from the inlet aperture to the sensor coating, and wherein the sensor coating is configured to change the electrical impedance across the pair of electrodes when the steam sterilant contacts the sensor coating.

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