Sensor assembly with wicking member for wetting up the liquid junction

Abstract

A sensor assembly for a body fluid analyzer includes a reference electrode reservoir containing a reference electrode; a membrane capable of or configured to be in fluid communication with the reference electrode reservoir; and a wicking member capable of or configured to be in fluid communication with the reference electrode reservoir, the wicking member configured to draw a reference fluid contained in the reference electrode reservoir toward the membrane when the membrane and the wicking member are exposed to the reference fluid.

Description

Technical Field

[0001] Cross - reference to related applications / incorporation by reference description The subject application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63 / 265,740, filed on December 20, 2021. The entire contents of the patent application referenced above are hereby expressly incorporated by reference into this specification.

Background Art

[0002] Modern blood analyzers are designed to use small amounts of a patient's blood. To do so, the analyzer transports the blood from a sampling device to a sensor and ultimately to a waste container. However, sensors used in conventional blood analyzers are susceptible to measurement errors caused by the presence or formation of air bubbles near the sensor.

[0003] The sensors used for these measurements are ion - specific electrodes or ion - selective electrodes (ISEs). These sensors are membrane - type electrochemical transducers that respond to specific ions. Biosensors are used not only in analyzers in conventional clinical laboratories but also in point - of - care testing devices. Biosensors convert biochemical signals into electrical signals.

[0004] Electrolytes are determined by potentiometric measurements, a form of electrochemical analysis. In potentiometric measurements, the potential or voltage between two electrodes in a solution is measured. These potentials also occur when a metal and its ions are present in the solution. By using a semi - permeable membrane for ions, different concentrations of ions can be separated. In these systems, a reference electrode and a measuring electrode are used. A constant voltage is applied to the reference electrode; the difference in voltage between the reference electrode and the measuring electrode is used to calculate the ion concentration in the solution.

[0005] Typical devices for measuring the ion content in a solution include a reference electrode and another potentiometric or "working" electrode. When these are immersed in a certain amount of the solution being analyzed (i.e., the test solution), the reference electrode and the working electrode together form an electrochemical cell. The reference electrode provides a constant potential relative to the potential detected by the working electrode from the test solution. The potential difference (i.e., voltage) between the cells (i.e., the potential difference between the working electrode and the reference electrode) is proportional to the activity of the ions in the test solution. Consequently, since this potential difference is related to the ion concentration in the test solution, the concentration is directly determined as a function of the voltage measured between the reference electrode and the working electrode.

[0006] The electrolyte is confined to an electrolyte reservoir behind a membrane that allows ion transport while restricting the flow of the solution being analyzed and the electrolyte itself. Thus, the electrolyte comes into contact with the test solution at a flow-restricted junction, thereby allowing ion flow by diffusion but not by convection. The membrane defines the region of the flow-restricted junction. A prior art reference electrode is typically a silver wire coated with silver chloride, immersed in an electrolyte solution of concentrated potassium chloride (or some equivalent formulation) contained in the electrolyte reservoir. Therefore, the reference electrode and electrolyte solution are contained within the electrolyte reservoir.

[0007] In a typical operating configuration, the working electrode and reference electrode are sequentially exposed to the test solution (e.g., a blood sample) and calibration solution (the calibration solution may be applied either before or after the blood sample). The calibration solution contains ions of known concentration to be measured. By comparing the potential difference between the reference electrode and the working electrode, depending on the sample and reagent, an accurately calibrated value for the ion concentration in the blood sample is determined.

[0008] To prevent salt crystallization and precipitation in the membrane during storage and transport of the sensor assembly, a plug, cap, or film is employed to keep the membrane sealed from the electrolyte during storage. When ready for use, the electrolyte reservoir can be "wet-up" to perform its function by moving the plug to expose the membrane to the electrolyte solution (e.g., salt solution). However, bubbles may form between the electrolyte solution and the membrane, thereby preventing the membrane from "wet-up". Furthermore, after the membrane has been "wet-up", bubbles may form on the membrane during use, resulting in undesirable changes or losses in the connection with the reference solution, adversely affecting the flow of ions across the membrane, and consequently causing measurement errors. Bubbles adhering to or near the membrane prevent the electrolyte solution from properly contacting or completely covering the membrane, thereby adversely affecting the maintenance and / or creation of a proper liquid junction in the membrane region, resulting in increased resistance and higher voltage measurements (errors). Therefore, bubbles formed on or near the membrane during "wet-up" have unfavorable consequences for the measurement errors of the sensor assembly. [Overview of the project] [Means for solving the problem]

[0009] For this purpose, there is a need for a sensor assembly having a reference electrode structure that can be shipped in a dry state and thus provide a long storage period, but can be "wet-up" for use without forming bubbles. In particular, there is a need for a sensor assembly that improves the maintenance and / or creation of liquid junctions across the membrane region, thereby avoiding and / or reducing bubbles in the sensor membrane region and thus eliminating and / or reducing measurement errors. The inventive concept disclosed herein relates to such a sensor assembly.

[0010] To assist those skilled in the art in the manufacture and use of the inventive concepts disclosed herein, refer to the accompanying drawings and illustrations. These are not intended to be drawn to scale, and for consistency, the same reference numerals are intended to refer to the same or similar elements. For clarity, not all components are labeled in all drawings. Certain configurations and viewpoints in the drawings are shown in an exaggerated, non-scale, or schematic manner for clarity and conciseness. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of a blood analyzer having a sensor assembly configured according to the inventive concept disclosed herein. [Figure 2] Figure 1 is an exploded perspective view of the blood analyzer, showing the sensor assembly removed from the blood analyzer. [Figure 3] This is a top perspective view of the sensor assembly. [Figure 4] Figure 3 is a bottom perspective view of the sensor assembly. [Figure 5] Figure 3 is a bottom plan view of the sensor assembly. [Figure 6] This is a top perspective view of the base of the sensor assembly housing. [Figure 7] This is a bottom plan view of the base in Figure 6, with a pair of covers removed for clarity. [Figure 8] This is a cross-sectional view taken along line 8-8 in Figure 6. [Figure 9] This is a cross-sectional view of the base taken along line 9-9 in Figure 6. [Figure 10] This is an exploded perspective view of the sensor assembly. [Figure 11] This is a partial perspective view of a sensor assembly with the cover removed to show a pair of sensor arrays. [Figure 12] This is a cross-sectional view taken along line 12-12 in Figure 3, showing the reference electrode housing space. [Figure 13A]A cross-sectional view taken along line 13A-13A of FIG. 3, showing the sealing material in the closed position. [Figure 13B] A cross-sectional view showing the sealing material of FIG. 13A in the open position. [Figure 14A] A cross-sectional view of another embodiment of the sealing material showing the sealing material in the closed position. [Figure 14B] A cross-sectional view showing the sealing material of FIG. 14A in the open position. [Figure 15A] A cross-sectional view of another embodiment of another reference electrode receiving space, sealing material, wicking member, and membrane assembly constructed in accordance with the present disclosure. [Figure 15B] A cross-sectional view of yet another embodiment of another reference electrode receiving space, sealing material, wicking member, and membrane assembly constructed in accordance with the present disclosure. [Figure 15C] A cross-sectional view of yet another embodiment of another reference electrode receiving space, sealing material, wicking member, and membrane assembly constructed in accordance with the present disclosure. [Figure 15D] A cross-sectional view of yet another embodiment of another reference electrode receiving space, sealing material, wicking member, and membrane assembly constructed in accordance with the present disclosure. **DETAILED DESCRIPTION OF THE INVENTION**

[0012] Before explaining at least one embodiment of the inventive concept in detail by way of exemplary drawings, experiments, results, and laboratory procedures, it is to be understood that the inventive concept is not limited in its application to the details of construction and the arrangement of components set forth in the following description or shown in the drawings, experiments, and / or results. The inventive concept is capable of other embodiments or of being practiced or carried out in various ways. The language used herein is intended to be given the broadest possible scope and meaning; the embodiments are intended to be exemplary but not exhaustive. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

[0013] Unless otherwise defined, scientific and technical terms used in connection with the presently disclosed and claimed inventive concepts shall have the meanings commonly understood by those of ordinary skill in the art. Further, unless the context specifically requires otherwise, singular terms shall include the plural and plural terms shall include the singular. The foregoing techniques and procedures are generally well known in the art and are performed in accordance with conventional methods described in various general and more specific references cited and discussed throughout this specification. The nomenclature utilized in connection with analytical chemistry, organic synthetic chemistry, and medicinal chemistry described herein, as well as their laboratory procedures and techniques, are well known and commonly used in the art. Standard techniques are used for chemical synthesis and chemical analysis.

[0014] All articles, compositions and / or methods disclosed and claimed herein can be made and executed without undue experimentation, considering the present disclosure. The articles, compositions and methods of the inventive concept are described from the perspective of specific embodiments, but it will be apparent to those of ordinary skill in the art that variations can be applied to the articles, compositions and / or methods, as well as the steps or sequences of steps of the methods, described herein without departing from the concepts, spirit and scope of the inventive concept. It will be understood that all such similar alternatives and modifications apparent to those of ordinary skill in the art are considered to be within the spirit, scope and concept of the inventive concept as defined by the appended claims.

[0015] When used in the context of the present disclosure, the following terms shall be understood to have the following meanings, unless otherwise indicated:

[0016] When used in conjunction with the term "comprising" in the claims and / or specification, the use of the word "a" or "an" can mean "one", but is also consistent with the meanings of "one or more", "at least one", and "one or two or more".

[0017] The use of the term “or” in the claims is used to mean “and / or” unless expressly indicated to refer only to substitutes, or unless the substitutes are mutually exclusive; however, this disclosure supports the definitions of “and / or” as referring only to substitutes.

[0018] Throughout this application, the term "about" is used to indicate that the value includes error-specific variations in the variation present between the device, the method employed to determine the value, or the object under test.

[0019] The use of the term "at least one" would be understood to include not just one, but any two or more quantities, including but not limited to 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" can extend to 100, 1000, or even more, depending on the term it is attached to; in addition, the quantity of 100 / 1000 should not be considered restrictive, as larger limit values ​​can also yield satisfactory results. Furthermore, the use of the term "at least one of X, Y, and Z" would be understood to include X only, Y only, and Z only, as well as any combination of X, Y, and Z.

[0020] As used herein and in the claims, the terms “comprising” (and any form of “comprising,” such as “comprise” and “comprises”), “having” (and any form of “having,” such as “have” and “has”), “including” (and any form of “including,” such as “includes” and “include”), or “containing” (and any form of “containing,” such as “contains” and “contain”) are inclusive or open-ended and do not exclude any additional unlisted elements or process steps.

[0021] As used herein, the term “or any combination thereof” refers to all permutations and combinations of the items listed before that term. For example, “A, B, C, or any combination thereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and, where the order is important in a particular context, BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Further examples explicitly include combinations that involve the repetition of one or more items or terms, such as BB, AAA, MB, BBC, AAABCCCC, CBBAAA, CABABB, etc. Those skilled in the art will understand that, unless particularly evident from the context, there is typically no limit to the number of items or terms in any combination.

[0022] As used herein, the term “sample” and its variations are intended to include, for example, biological tissues, biological fluids, chemical fluids, chemicals, suspensions, solutions, slurries, mixtures, aggregates, tinctures, slides, powders, or other preparations of biological tissues or fluids, synthetic analogues of biological tissues or fluids, bacterial cells (prokaryotic or eukaryotic), viruses, single-celled organisms, lysed living cells, fixed living cells, fixed living tissues, cell cultures, tissue cultures, genetically modified cells and tissues, genetically modified organisms, and combinations thereof.

[0023] As used herein, the term “wet-up” will be understood to refer to the hydration process (e.g., of the membrane) from the time the sensor is placed in the fluid analyzer until a stable signal is obtained from the calibration reagent (e.g., reference fluid). A stable signal is obtained when a liquid junction is formed and maintained. Bubbles formed in or near the membrane during wet-up can adversely affect the stability of the signal by interfering with the formation or maintenance of the liquid junction. Therefore, improvements to wet-up as described herein include obtaining and / or maintaining a stable signal, and thus a liquid junction in a membrane that is bubble-free or has reduced bubbles.

[0024] As used herein, the phrase “fluid-communicable or configured to be fluid-communicable” refers to direct or indirect fluid communication between two elements / compartments that allows fluid flow between them. In addition, the phrase “fluid-communicable or configured to be fluid-communicable” includes cases where the flow point between two elements / compartments is sealed or otherwise blocked, but the two elements / compartments are capable of having fluid flow between them by puncture, perforation, or otherwise removal of any sealant / plug formed in or between them.

[0025] The following detailed description of embodiments of the Outline of the Invention includes numerous specific details to provide a more complete understanding of the Concept of the Invention. However, it will be apparent to those skilled in the art that the Concept of the Invention within the scope of this Disclosure can be practiced without these specific details. In other cases, well-known configurations are not described in detail to avoid unnecessarily complicating this Disclosure.

[0026] Finally, as used herein, any reference to “one embodiment” or “a particular embodiment” means that any specific element, configuration, structure, or characteristic described in relation to an embodiment is included in at least one embodiment. The phrase “in one embodiment” appearing in various parts of this specification does not necessarily refer to the same embodiment.

[0027] The inventive concepts disclosed and / or claimed herein relate, in general, to sensor assemblies for body fluid analyzers. The sensor assembly includes a reference electrode container containing a reference electrode; a membrane that is or is configured to be fluid-communicated with the reference electrode container; and a wicking member that is or is configured to be fluid-communicated with the reference electrode container. The wicking member is configured to draw the reference fluid contained in the reference electrode container toward the membrane when the membrane and the wicking member are exposed to the reference fluid (i.e., when the membrane and the wicking member are fluid-communicated with the reference electrode container). When the membrane and the wicking member are not exposed to the reference fluid (i.e., sealed from the reference fluid), the membrane and the wicking member are not fluid-communicated with the reference electrode container. The membrane and the wicking member may be located inside the reference electrode container, or may be located outside the reference electrode container but be fluid-communicated with the reference electrode container.

[0028] In another embodiment, the inventive concepts disclosed and claimed herein generally relate to a fluid analyzer comprising: a sample receiving assembly having a sample probe having a fluid inlet and a fluid outlet; a fluid waste assembly; and a sensor assembly fluid-communicating with the sample receiving assembly and the fluid waste assembly. The sensor assembly comprises: a reference electrode container including a reference electrode; a membrane that is fluid-communicating with or configured to fluid-communicate with the reference electrode container; and a wicking member that is fluid-communicating with or configured to fluid-communicate with the reference electrode container. The wicking member is configured to draw the reference fluid contained in the reference electrode container toward the membrane when the membrane and the wicking member are exposed to the reference fluid (i.e., when the membrane and the wicking member are fluid-communicating with the reference electrode container). When the membrane and the wicking member are not exposed to the reference fluid (i.e., sealed from the reference fluid), the membrane and the wicking member are not fluid-communicating with the reference electrode container. The membrane and the wicking member may be located inside the reference electrode container, or may be located outside the reference electrode container but be fluid-communicating with the reference electrode container.

[0029] In another aspect, the inventive concept disclosed and claimed herein generally relates to a method for forming a sensor assembly for a body fluid analyzer. The method includes positioning a membrane to include a reference electrode and be configured to include a reference fluid and to be in fluid communication with a reference electrode container, and positioning a wicking member to draw the reference fluid toward the membrane when the membrane and wicking member are exposed to the reference fluid. The membrane and wicking member are located inside or outside the reference electrode container.

[0030] Described herein and shown in the accompanying drawings are some non-limiting embodiments of an apparatus of the now claimed and disclosed inventive concept, used in conjunction with a sampling syringe and a liquid sample analyzer for removing air or other gaseous bubbles from a fluid sample for analysis by a fluid sample analyzer. The fluid sample is generally of biological origin. "Fluid" means any substance that does not have a fixed shape and readily yields to external pressure.

[0031] Referring here to the drawings, more specifically Figures 1 and 2, an exemplary blood analyzer 10 for analyzing one or more samples for one or more target analytes is illustrated. In certain embodiments, the blood analyzer 10 is a point-of-care analyzer or a blood analyzer as known in the art. Exemplary point-of-care analyzers are available from Siemens Healthcare Diagnostics, Inc. and are marketed under the trademarks RAPIDLab 1200, RapidLab 348EX, RAPIDPoint 500, RAPIDLab 248 / 348, RAPIDPoint 400 / 405, and RAPIDPoint 340 / 350 systems. Other commercially available point-of-care devices are available from Roche Molecular Systems Inc., Medica Corp., Radiometer Medical (Denmark), and Nova Biomedical Corp.

[0032] The blood analyzer 10 includes a housing 12 for housing and supporting multiple sample analysis components and / or modules. These components may include a sample receiving assembly 14, a fluid tubing assembly 16, a sensor assembly 18, and a reagent assembly 20. The housing 12 may also support a display screen 22 for showing the progress of the test.

[0033] The fluid sample introduced into the blood analyzer 10 may include any biological material taken from the subject, such as body fluids, pathogens, or abscesses, collected from the subject by appropriate methods and devices known in the art. Examples of body fluids include, but are not limited to, urine, whole blood, serum, plasma, saliva, cerebrospinal fluid, pleural fluid, dialysate, nasopharyngeal swabs, vaginal swabs, tears, and tissues. Further examples of the sample may include any appropriate buffers, diluents, etc., required or desired for a particular sample. In certain embodiments, the sample includes a blood sample, which may be: a whole blood sample containing plasma and whole blood cells; a plasma sample; or a serum sample. In certain embodiments, the sample includes a whole blood sample. The whole blood sample may contain red blood cells, platelets, etc. In other embodiments, the blood sample includes a plasma sample. To obtain a plasma sample, the sample is processed to remove multiple whole blood cells using known methods and components, such as centrifugation or commercially available porous membranes.

[0034] The sample receiving assembly 14 is adapted to introduce a liquid sample from a transport container (not shown) into the sensor assembly 18 for analysis. An example of the sample receiving assembly 14 is disclosed in U.S. Patent No. 10,928,409, which is expressly incorporated herein by reference. In one example, the sample receiving assembly 14 includes a sample probe 24 which may be rotatable to a selected position so that the sample probe 24 can receive fluid samples from different types of sample transport containers. Examples of sample transport containers include syringes, vacuuminers, and capillary tubes (not shown). The sample probe 24 is also oriented in standby mode (e.g., vertically) to seal the fluid outlet 26 of the reagent assembly 20, thereby allowing the sample receiving assembly 14 to transport the fluid from the reagent assembly 20 to the sensor assembly 18.

[0035] The reagent assembly 20 holds multiple reagent fluids used for testing. The reagents are supplied in a reservoir such as a sealed bag or bottle (not shown). The reagent assembly 20 may include one or more reservoirs pre-filled with processing fluids having known compositions (known to those skilled in the art: QC1, QC2, QC3, CRL3 (S1940), CRL2 (S1930), RINSE / CAL1 (S1920)). Those skilled in the art will understand that other chemicals may be supplied depending on the exact test to be desired.

[0036] The reagent assembly 20 may include a rubber nipple (not shown) defining a fluid outlet 26, for example, when sealed and engaged with the sample receiving assembly 14, so as to allow the reagent assembly 20 to fluidly communicate with the sensor assembly 18 and allow reagent fluid to flow from the reagent assembly 20 to the sensor assembly 18. The reagent assembly 20 may be integrated as a component of the blood analyzer 10, or otherwise configured to be removable / disposable.

[0037] The sensor assembly 18 includes a sensor used to contact a fluid sample. The sensor assembly 18 may be integrated with the blood analyzer 10, or it may be a removable / disposable module unit. The sensor assembly 18 may communicate directly or indirectly with a computing unit (not shown) that can collect, store, and analyze analytical test results from the sensor according to known methods. After the fluid sample is delivered to the sensor assembly 18, the blood analyzer 10 can introduce fluid from the reagent assembly 20 and prepare the blood analyzer 10 for the introduction of subsequent fluid samples.

[0038] Referring here to Figures 3 to 14, the sensor assembly 18 is shown detached from the housing 12 of the blood analyzer 10. In one non-limiting embodiment, the sensor assembly 18 includes a housing 30 (Figures 3 to 13), at least one sensor 32 (Figures 3, 9, and 10), a reference electrode 34 (Figure 12), a reference fluid 36 (Figures 12, 13A, 13B, 14A, and 14B), a sealing material such as a membrane 150 (Figures 13A to 13B and 14A to 14B), a plug 40 (Figures 13A and 13B), or a perforated barrier 170 (Figures 14A and 14B) defining the region of the fluid junction 38, and a wicking member 42 (Figures 13A to 13B and 14A to 14B).

[0039] The housing 30 is configured to define a fluid inlet 44, a fluid outlet 46, and a fluid channel 48 extending between the fluid inlet 44 and the fluid outlet 46. The housing 30 has a sensor housing space 50 (also called the sensor container 50) and a reference electrode housing space 52 (also called the reference electrode container 52) that are separated from each other. The housing 30 supports various components for performing chemical (e.g., electrochemical) assays on a fluid sample.

[0040] As shown in Figure 3, in one non-limiting embodiment, the housing 30 is shown to be substantially rectangular in shape. However, those skilled in the art will readily understand that the housing 30 may be any shape that can achieve the currently disclosed and / or claimed inventive concept, including but not limited to circular, triangular, square, pentagonal, hexagonal, heptagonal, octagonal, nonagonal, decagonal, or any polygon. Furthermore, the housing 30 may be constructed of any suitable material, including but not limited to synthetic polymers and / or naturally occurring or naturally derived polymers (both organic and / or inorganic), such as thermoplastic polymers, thermosetting polymers, elastomers, and / or synthetic fibers, such as low-density polyethylene, high-density polyethylene, polystyrene, polyvinyl chloride, styrene-butadiene, polyacrylic, polyvinyl acetate, acrylic, acrylic acid, and acrylate polymers, and combinations thereof, including but not limited to opaque and / or transparent and / or translucent materials.

[0041] The housing 30 is constructed from several different components assembled together. In one non-limiting embodiment of the currently disclosed and / or claimed inventive concept, the housing 30 includes a base 54, a cover 56, and a plug assembly 58 (Figure 12). The base 54 serves as a substrate for an integrated analyte detection system, which may include an electrochemical system. In one non-limiting embodiment, referring to Figures 5 and 6, the base 54 has a top surface 62 and a bottom surface 64. The top surface 62 allows and / or facilitates the attachment of additional components to the base 54. The base 54 may include a fluid inlet 44 of the housing 30. The fluid inlet 44 extends through the base 54 from the bottom surface 64 to the top surface 62 and intersects with a fluid channel 48 for a fluid sample (Figures 13A, 13B).

[0042] In one non-limiting embodiment, the base 54 can define part of the fluid channel 48. More specifically, the fluid inlet 44 can intersect one end of a groove 66 (Figure 6) extending along the top surface 62 of the base 54. At the other end of the groove 66, a port 68 (Figure 7) extends from the top surface 62 to the bottom surface 64 and intersects one end of an intersecting groove 70 (Figure 7) formed on the bottom surface 64 of the base 54. The intersecting groove 70 extends along part of the bottom surface 64 of the base 54. The intersecting groove 70 is covered by a cover 72 (Figure 5) to define an intersecting channel. The port 74 (Figure 7) extends from the other end of the intersecting groove 70 from the bottom surface 64 to the top surface 62 and intersects one end of the groove 76 (Figure 6) extending along the top surface 62 of the base 54. The groove 76 may extend parallel to the groove 66.

[0043] At the other end of groove 76, port 78 (Figures 7 and 8) extends from the top surface 62 to the bottom surface 64, and port 78 intersects with one end of groove 80 formed in the bottom surface 64 of base 54. Groove 80 extends along a portion of the bottom surface 64, and the other end of groove 80 intersects with port 82 (Figures 7 and 8), which extends from the bottom surface 64 to the top surface 62. The top surface 62 of base 54 within the reference electrode housing space 52 includes a projection 84 (Figures 6 and 8). Port 82 extends to the distal end of projection 84. The distal end of projection 84 has a slot 86, and port 82 intersects with one end of slot 86 (Figures 6 and 7). The other end of slot 86 intersects with one end of port 88, which extends from the top surface 62 to the bottom surface 64, so that port 82, slot 86, and port 88 define a substantially U-shaped flow path (Figure 8).

[0044] Port 88 intersects with one end of a groove 90 (Figure 8) formed in the bottom surface 64 of the base 54. The groove 90 extends along a portion of the bottom surface 64, and the other end of the groove 90 intersects with port 92 (Figure 9), which extends from the bottom surface 64 to the top surface 62. Grooves 80 and 90 are covered by a cover 94 (Figure 5) to define a pair of channels.

[0045] Port 92 intersects with one end of a groove 96 (Figure 9) that extends along a portion of the top surface 62, and the other end of the groove 96 intersects with a fluid outlet 46 that extends from the top surface 62 to the bottom surface 64 of the base 54.

[0046] Referring here to Figures 9 to 11, in one non-limiting embodiment, at least one analyte sensor 32 may be a pair of sensor arrays 100a and 100b. However, it should be understood by those skilled in the art that the sensor assembly 18 may include any number of analyte sensor arrays. Sensor arrays 100a and 100b may be the same or different in both configuration and the electrochemical assay / measurement performed. In addition, although sensor arrays 100a and 100b are shown in Figures 9 and 11 as being on the top surface 62 of the base 54, they may be on the same or different surfaces to achieve the inventive concept currently disclosed and / or claimed. For example, sensor array 100a may be on the top surface 62 of the base 54 and sensor array 100b may be on the bottom surface 64 of the base 54; or both sensor arrays 100a and 100b may be on the bottom surface 64.

[0047] Examples of suitable sensor arrays are disclosed in International Publication Nos. 2020 / 05692 and International Publication Nos. 2020 / 005697, both of which are expressly incorporated herein by reference. Sensor arrays 100a and 100b may include a sensor panel 102 having an upper surface and a lower surface. In some embodiments, one or more analyte sensors 108 are located on the sensor panel 102. The sensor panel 102 may be made from materials including, but not limited to, ceramics, plastics, and / or equivalents.

[0048] In some embodiments, the sensor arrays 100a and 100b may include an adhesive layer 110 having an upper surface 112 and a lower surface 114. A pair of slots 116 may extend the length of the adhesive layer 110. The upper surface 112 of the adhesive layer 110 is bonded and fixed to the lower surface 106 of the sensor panel 102. The lower surface 114 of the adhesive layer 110 is fixed to the upper surface 62 of the base 54 with the slots 116 aligned with grooves 66 and 76. In some embodiments, the adhesive layer 110 may be optional.

[0049] Sensor arrays 100a and 100b are fixed above grooves 66 and 76, respectively, defining a portion of the fluid channel 48. The fluid channel 48 is configured so that the sample to be examined or the fluid sample to pass along grooves 66 and 76 to come into contact with one or more analyte sensors 108.

[0050] Referring here to Figures 3, 10, and 12-14, the cover 56 of the housing 30 is fixed to the base 54 with the sensor arrays 100a and 100b sandwiched between them. The cover 56 has a first end 130, a second end 132, a first side 134, a second side 136, and a bottom surface 138. The bottom surface 138 is configured to connect to the top surface 62 of the base 54 with the sensor arrays 100a and 100b positioned between them, so that the cover 56 defines a sensor housing space 50 adjacent to the first end 130 of the cover 56. The bottom surface 138 of the cover 56 may have a number of openings 140 corresponding to the analyte sensor 108 to allow electrical pins (not shown) to contact the analyte sensor 108.

[0051] The reference electrode housing space 52 of the housing 30 is defined adjacent to the second end 132 of the cover 56 by a plurality of side walls 142a to 142d. The side walls 142d separate the sensor housing space 50 from the reference electrode housing space 52. The reference electrode housing space 52 is sealed by a cap 144. The cap 144 can support the reference electrode 34 so that it extends into the reference electrode housing space 52 (Figure 12). The reference electrode 34 may be, for example, a silver wire coated with silver chloride. The reference fluid 36 is placed in the reference electrode housing space 52 so that the reference fluid 36 is in contact with the reference electrode 34. The reference fluid 36 may be an electrolyte solution such as an aqueous potassium chloride solution (or an equivalent preparation).

[0052] The reference fluid 36 comes into contact with the fluid sample in the fluid channel 48 (e.g., by forming an ionic and / or electrical connection) in a flow-restricting region such as a membrane, film, barrier, constriction, or boundary region. The reference fluid 36 forms a liquid junction 38 with the fluid sample in or near the flow-restricting region. A liquid junction is the boundary between two electrolyte solutions of different compositions (e.g., the reference fluid 36 and the fluid sample) where a potential difference called the liquid junction potential occurs. The flow-restricting region may be a porous region (having one or more pores or holes) that allows ion flow by diffusion but restricts fluid flow to define a restricted diffusion-type liquid junction. In one non-limiting embodiment, the flow-restricting region includes a membrane 150 (Figures 13A-13B and 14A-14B) located between the reference electrode housing space 52 and the fluid channel 48, defining the region of the liquid junction 38. Therefore, the membrane 150 fluidly separates the reference electrode housing space 52 from the sensor housing space 50 (i.e., restricts or prevents fluid flow but allows ion flow). The membrane 150 is positioned around the projection 84 of the base 54 so as to cover the slot 86. The projection 84 extends upward through an opening provided through the bottom surface 138 of the cover 56 on the base 54. The membrane 150 may be disc-shaped and is fixed around the projection 84 by a fixing member such as an O-ring 152.

[0053] The film 150 is formed from and / or treated (e.g., coated) with one or more suitable materials, such as polymer materials. In one non-limiting embodiment, all or part of the film 150 may be made of a hydrophilic material. In yet another embodiment, all or part of the film 150 is treated (e.g., coated) with a hydrophilic material. A film formed from or containing a hydrophilic material is advantageous in that it helps to maintain the stability of the liquid junction in the film 150 by strengthening the film 150 to "wet up" so that it can perform its functional function and by helping to prevent bubble formation. Examples of suitable non-exclusive materials for the film 150 or film coating include, for example, polypropylene, polyethylene, polyvinyl chloride, and modified polyvinyl chloride, as well as any similar hydratable polymer films known to those skilled in the art. Other examples of suitable non-exclusive materials may be cellulose acetate, or porous glass, or ceramics. Heterogeneous films may also be used instead of homogeneous films. In this specification, the term "heterogeneous film" refers to a film formed from at least two different materials and / or treated (e.g., coated) with at least two different materials. In one exemplary embodiment, to enhance "wet-up," the surface of the film 150 facing the fluid channel 48 has higher hydrophilicity than the surface of the film 150 facing the reference electrode housing space 52, and the surface of the film 150 facing the reference electrode housing space 52 may contain a hydrophobic material or a material having lower hydrophilicity compared to the surface of the film 150 facing the fluid channel 48. Alternatively, in another embodiment, the surface of the film 150 facing the reference electrode housing space 52 has higher hydrophilicity than the surface of the film 150 facing the fluid channel 48.

[0054] The reference electrode housing space 52 is configured to house the reference fluid 36. The sensor assembly 18 may or may not be housed and shipped with the reference fluid 36 located in the reference electrode housing space 52, but in either embodiment, the membrane 150 is sealed to prevent contact with the reference fluid 36 until operationally desired. In one embodiment shown in Figure 12, a plug assembly 58 is provided to seal the membrane 150. The plug assembly 58 may include a lever 154 (Figure 10) pivotably connected to the cover 56 and a bladder 156 (Figure 10) connected to one end of the lever 154. A plug 40 (Figures 10 to 13B) is connected to the other end of the lever 154. The plug 40 may be a rigid or semi-rigid cap. Actuation of the bladder 156 by an actuator (not shown) causes the lever 154 to move the plug 40 from a closed position (Figure 13A) where the plug 40 seals the liquid junction 38 (e.g., membrane 150) from the reference fluid 36, to an open position (Figure 13B) where the reference fluid 36 is in fluid communication with the fluid passage 48 and forms a liquid junction 38 on or near the membrane 150.

[0055] In one non-limiting embodiment, the bottom surface 138 of the cover 56 includes a well or pocket 160 in which the membrane 150 is positioned to control ion diffusion. A portion of the plug 40 engages with the pocket 160, allowing the membrane 150 to be sealed from the reference fluid 36. Because the fluid space used in the sensor assembly 18 is small, when the plug 40 is moved to the open position and the membrane 150 is exposed to the reference fluid 36, bubbles form between the reference fluid 36 and the membrane 150, thereby preventing the membrane 150 from "wetting up" and causing measurement errors in the sensor assembly 18.

[0056] The wicking member 42 is configured to be in fluid communication with the reference electrode housing space 52 (for example, located in the reference electrode housing space 52, but not limited thereto) and positioned to be in contact with the surface of the membrane 150. The wicking member 42 is configured to seal off the reference fluid 36 when the plug 40 is in the closed position, and to draw the reference fluid 36 into contact with the membrane 150 when the plug 40 is in the open position. In the open position, the wicking member 42 is configured to maintain contact between the reference fluid 36 and the membrane 150, and thus to maintain the fluid junction 38.

[0057] In Figures 13A-13B and 14A-14B, the wicking member 42 is shown as a strip located in the pocket 160, where one end or surface of the wicking member 42 is in contact with the membrane 150. However, it will be understood that the wicking member 42 can be constructed in various shapes and sizes. In one embodiment, two or more wicking members 42 may also be employed. One or more wicking members are positioned to be in contact with at least a portion of the surface of the membrane 150 facing the reference electrode housing space 52. The wicking member 42 absorbs the reference fluid 36 and draws the reference fluid 36 to the surface of the membrane 150. By bringing the reference fluid 36 into contact with the membrane 150, the wicking member 42 helps prevent the formation of bubbles and thus helps maintain and / or create a liquid junction in the membrane 150, thereby reducing measurement errors. In one embodiment, the wicking member 42 is made of a hydrophilic material or is coated with a hydrophilic material. Alternatively, the wicking member 42 may be formed and / or coated from a combination of hydrophobic and hydrophilic materials, the hydrophilic portion of which is exposed to the reference fluid 36 during the operation of the sensor assembly 18. As used herein, “wicking member” refers to any substance or material, matrix, mixture or composite material having an open structure, such as an open mesh. For example, a wicking member may be formed from a woven and / or nonwoven (extruded) material made from filament fibers, or from a sintered material (e.g., a non-fibrous material made from multiple pellets, such as polymer or metal pellets). Other non-limiting exemplary materials include, for example, cellulose, polyester, nylon, aramid, polyethylene, and / or glass fibers, which may be used as suitable for the application from among the many available fibers. Suitable materials for the wicking member 42 are Hi-Flow® Plus Membrane and SureWick® Pad Materials, commercially available from EMD Millipore Corporation, (Billerica, Massachusetts).

[0058] To seal the wicking member 42 when in the closed position, the plug 40 can be hollow, as shown in Figures 13A and 13B, and has an open bottom through which the wicking member 42 is positioned. The wicking member 42 is attached to the inside of the pocket 160, such as by attaching it to the surface of the membrane 150 using a suitable adhesive or by interference or capture of the member.

[0059] In another embodiment shown in Figures 14A and 14B, instead of the plug 40 or plug assembly 58, the sealant may be a perforated barrier 170, such as a film or coating, located on the bottom surface 138 of the cover 56 in the closed position (Figure 14A) to seal the fluid junction 38 (e.g., membrane 150) from the reference fluid 36. In the closed position (i.e., the position that is not perforated or broken), the perforated barrier 170 is configured to sealably separate the membrane 150 and the wicking member 42 from the reference fluid 36. In one embodiment, as shown in Figure 14A, to seal the membrane 150 and the wicking member 42, the perforated barrier 170 extends across a pocket 160 containing the membrane 150 and the wicking member 42. The perforated barrier 170 may or may not be in direct contact with the surface of the wicking member 42. In one embodiment, the perforated barrier 170 may be made of a hydrophobic material to further facilitate the prevention of the reference fluid 36 from coming into contact with the membrane 150 and / or the wicking member 42 when the perforated barrier 170 is in the closed position.

[0060] When the sensor assembly 18 is activated, the perforable barrier 170 (e.g., a film or coating) is broken or perforated so that the perforable barrier 170 is in an open position (Figure 14B). The perforable barrier 170 can be broken or perforated by tearing or puncturing the perforable barrier 170 in order for the reference fluid 36 to form a fluid junction 38 in fluid communication with the fluid passage 48. In one exemplary embodiment, the perforable barrier 170 is broken or perforated by a mechanical perforator (not shown), such as a perforating or puncturing element, which is mounted on the housing 30 and configured to be actuated or moved toward the perforable barrier 170 (e.g., by a user or actuator) when the sensor assembly 18 is activated. Alternatively, or in addition, the perforable barrier 170 may be broken or perforated by an electropermechanism such as a spark, impact, or vibration (e.g., ultrasonic) signal, which is configured to break the perforable barrier 170 when the sensor assembly 18 is activated, exposing the membrane 150 to the reference fluid 36. Thus, perforation or breaking of the perforable barrier 170 by a tearing or puncturing element (not shown) exposes the wicking member 42 to the reference fluid 36, which in turn promotes the attraction of the reference fluid 36 to the membrane 150 for enhanced "wet-up" and reduced bubble formation.

[0061] In the embodiments shown in Figures 13A-13B and 14A-14B, the wicking member 42 and the membrane 150 are located inside the reference electrode housing space 52. However, importantly, a portion of the wicking member 42 is positioned to contact a portion of the membrane 150, and the wicking member 42 and the membrane 150 are configured to be sealed by a sealing material (e.g., a plug or a perforated barrier) to prevent fluid communication or contact with the reference fluid 36 contained in the reference electrode housing space 52 until operationally desired. Thus, as shown in Figures 15A-15D, the wicking member and the membrane may be located outside or outside the interior of the reference electrode housing space, which is within the scope of this disclosure. In one alternative embodiment, as shown in Figure 15A, a portion of the wall 180 of the reference electrode housing space 52a (e.g., a portion of the bottom wall 180) has a gap or opening 182 that is covered by a sealing material 184 (e.g., a plug or a perforated barrier). The first end 186 or surface of the wicking member 42a is configured to be located in the gap 182 or otherwise to be in contact with the sealant 184 extending across the gap 182. The wicking member 42a extends from its first end 186, which is away from the reference electrode housing space 52a (for example, away from the bottom wall 180 of the reference electrode housing space 52a), toward a second end 188 or surface of the wicking member 42a, which is on the opposite side of the first end 186. The second end 188 of the wicking member 42a is positioned to be in contact with at least a portion of the surface 190 of the film 150a that faces the reference electrode housing space 52a. In this embodiment, the sealing material 184 (e.g., a plug or a perforated barrier) may be similar to the sealing material of the plug 40 and perforated barrier 170 in Figures 13A-13B and 14A-14B, except that when the sealing material 184 is in the closed position, it is configured to seal a gap 182 or opening in a portion of the wall 180 of the reference electrode housing space 52a (e.g., a portion of the bottom wall 180), and when the sealing material 184 (e.g., a plug or a perforated barrier) is in the open position, it is configured to expose the gap 182, and thus expose the wicking member 42a located inside, allowing the reference fluid to come into contact with the membrane 150a.

[0062] In Figure 15A, the wicking member 42a extends into a gap 182 in the wall 180 of the reference electrode housing space 52a such that the first end 186 of the wicking member 42a is substantially coplanar with the inner surface of the wall 180 of the reference electrode housing space 52a, and the wicking member 42a within the gap 182 is covered by the sealant 184 located within the reference electrode housing space 52a. However, it will be understood that the scope of this disclosure includes positioning the wicking member and sealant at any location inside, inside, outside, or outside the reference electrode housing space.

[0063] Instead of a sealant extending across the gap in the bottom wall of the reference electrode housing space, the sealant is arranged to connect to the gap or to seal a mating member extending through the gap until operationally desired. The mating member may be a well or pocket in which at least a portion of the wicking member (e.g., a first end) is located, and the sealant mates with the mating member (e.g., the upper surface of the well or pocket) to seal the wicking member and membrane from fluid communication with the reference fluid until the sealant is released. The mating member may have a similar design and function to the well or pocket 160 shown in Figures 13A-13B and 14A-14B, except that at least a portion of the mating member is located outside the reference electrode housing space and is aligned with the gap in the wall of the reference electrode housing space.

[0064] In one non-limiting embodiment (Figure 15B), a fitting member (e.g., a well of pocket) is connected to the outer wall of the reference electrode housing space and can extend away from the interior of the reference electrode housing space, where the sealant is configured to extend across the gap along the outer wall of the reference electrode housing space. As seen in Figure 15B, the wicking member 42b is located outside and on the exterior of the reference electrode housing space 52b. The sealant 184b is positioned on the first end 186b of the wicking member 42b and covers the gap / opening 182b of the wall 180b of the reference electrode housing space 52b. The mating member 192 extends downward from the side of the first end 186b of the wicking member 42b (i.e., away from the reference electrode housing space 52b) and around at least a portion of that side, such that at least a portion of the wicking member 42b (i.e., the first end 186b) is located inside the mating member 192 (i.e., inside the side wall of the mating member 192). The sealant 184b is positioned to extend across the side wall of the mating member 192 so that the first end 186b of the wicking member 42b and the gap / opening 182b are sealed in the closed position when fluid communication between the reference electrode housing space 52b and the wicking member 42b is not desired.

[0065] In another non-limiting embodiment (Figure 15C), the mating member (e.g., a well of pocket) is coplanar with the wall of the reference electrode housing space and extends outward from the gap to the outside of the reference electrode housing space, where the sealant is coplanar with or aligned with the inside of the bottom wall of the reference electrode housing space. In Figure 15C, the wicking member 42c is positioned in the gap 182c such that the first end 186c of the wicking member 42c is positioned inside the wall 180c. In addition, the sealant 184c covers the first end 186c of the wicking member 42c, and the mating member 192c extends to its side to close the gap / opening 182c in the wall 180c of the reference electrode housing space 52c.

[0066] In yet another embodiment (Figure 15D), the mating member (e.g., a well of pocket) is positioned to extend through the gap such that a first end of the mating member is located inside the reference electrode housing space and a second end of the mating member is located outside the reference electrode housing space. In this embodiment, the wicking member is positioned both inside and outside the reference electrode housing space such that a first end of the wicking member is located inside the reference electrode housing space and is in contact with the sealant, while a second end of the wicking member is located outside the reference electrode housing space and is in contact with the membrane. In particular, in Figure 15D, the wicking member 42c extends into the reference electrode housing space 52d through a gap 182d in the wall 180d. The sealant 184d covers the first end 186d of the wicking member 42d, and the mating member 192d covers at least a portion of the side surface of the wicking member 42d that extends through the wall 180d of the reference electrode housing space 52d. In all of Figures 15A to 15D, the second ends 188 / 188b / 188c / 188d of the wicking members 42a / 42b / 42c / 42d, as well as the films 150a / 150b / 150c / 150d, are located outside the reference electrode housing spaces 52a / 52b / 52c / 52d.

[0067] During use, the sensor assembly 18 is inserted into and secured within the housing 12. The sealing material (e.g., plug 40, perforated barrier 170, or sealing material 184) moves or acts from a closed position to an open position, exposing the wicking member 42 and the membrane 150 to the reference fluid 36, thereby "wetting up" the membrane. The wicking member 42 assists and enhances the "wetting up" of the membrane 150 for an improved operating method of the sensor assembly 18. For example, the wicking member 42 enhances the "wetting up" cycle of the sensor assembly 18 by drawing the reference fluid 36 toward the membrane 150 and / or pocket 160, thereby reducing or preventing bubble formation on the membrane 150, and thereby improving the complete fluid coverage of the area around the membrane 150 and / or pocket 160, which helps prevent bubble formation and push any formed bubbles away from the membrane 150, thus improving the "wetting up" of the membrane 150. The wicking member 42 attracts the reference fluid 36 toward the membrane 150, thereby favorably promoting and maintaining contact between the reference fluid 36 and the membrane 150, thereby improving the creation and maintenance of the fluid junction 38 in the open position. The presence of the wicking member 42, due to the hydrophilicity of the material of the wicking member 42, can reduce or prevent bubble formation on the membrane 150 during the test cycle of the sensor assembly 18. The wicking member 42 can also reduce or prevent bubble formation by eliminating and / or reducing convective fluid motion on the membrane 150, where convective fluid motion can unfavorably introduce gas (and therefore bubbles) as the reference fluid 36 is heated (e.g., to 37°C) during the test cycle. Heating the reference fluid 36 can change (i.e., decrease) the gas solubility, which can lead to the generation of gas (e.g., oxygen and nitrogen) from the reference fluid 36, thereby unfavorably promoting bubble formation on or near the membrane 150. After a predetermined number of tests on the fluid sample, the sensor assembly 18 can be removed from the housing 12 as a module unit. [Examples]

[0068] The following examples are intended to illustrate specific useful embodiments and aspects of the currently disclosed and claimed inventive concept and are not intended to limit its scope. [Examples]

[0069] Four sensor cartridges without wicking material were tested. Each sensor assembly showed poor wet-up. Each sensor assembly formed bubbles on the film within 24 hours. The potential difference signal began to drift and eventually recorded measurements indicating loss of reference. [Examples]

[0070] Three sensor assemblies, each equipped with a wicking member, were tested. None of the sensor assemblies failed during the initial wet-up period, and none failed during the one-week operating period. In this embodiment, a cellulose wicking material was used as the wicking member. However, as mentioned above, it should be understood that any material with wicking properties can be used as a wicking member.

[0071] From the above description, it is clear that the inventive concepts disclosed herein are as applicable as those inherent to the inventive concepts disclosed herein to achieve the purposes described herein and to obtain their benefits. While exemplary embodiments of the inventive concepts disclosed herein are described for the purposes of this disclosure, it will be understood that numerous modifications are readily suggested to those skilled in the art and achieved without departing from the scope of the inventive concepts disclosed herein and defined by the appended claims.

[0072] Non-exclusive exemplary embodiments The following is a list of non-limiting exemplary embodiments of the inventive concept disclosed herein.

[0073] An exemplary sensor assembly for a body fluid analyzer, comprising: a reference electrode container comprising a reference electrode and configured to contain a reference fluid; a membrane configured to communicate with the reference electrode container; and a wicking member configured to communicate with the reference electrode container and configured to draw the reference fluid toward the membrane when the membrane and the wicking member are exposed to the reference fluid.

[0074] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, wherein the wicking member is in contact with the membrane.

[0075] The wicking member comprises a hydrophilic material, as described in one of the preceding exemplary embodiments of the exemplary sensor assembly.

[0076] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, further comprising a sealing material located within a reference electrode container and movable from a closed position to an open position, wherein in the closed position the wicking member and membrane are sealed from the reference fluid, and in the open position the wicking member and membrane are exposed to the reference fluid.

[0077] The sealing material is a plug, as described in one of the preceding exemplary embodiments of the exemplary sensor assembly.

[0078] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, wherein the reference electrode container has a pocket, the plug is fitted into the pocket in a closed position, and the wicking member is positioned between the plug and the membrane within the pocket.

[0079] The sealing material is a perforable barrier configured to be perforated, as described in one of the preceding exemplary embodiments of the exemplary sensor assembly.

[0080] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, wherein the reference electrode container has a pocket, a perforable barrier covers the pocket in a closed position, and a wicking member is positioned between the perforable barrier and the membrane within the pocket.

[0081] The exemplary sensor assembly described in any one of the preceding exemplary embodiments, wherein the membrane and / or wicking member is located inside the reference electrode container.

[0082] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, wherein the membrane and / or wicking member is located outside the reference electrode container.

[0083] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, wherein the first end of the wicking member is located inside the reference electrode container, the second end of the wicking member is located outside the reference electrode container, and the second end of the wicking member is in contact with a membrane, the membrane is located outside the reference electrode container.

[0084] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, further comprising a housing including a reference electrode container having a fluid inlet, a fluid outlet, and a fluid channel extending between the fluid inlet and the fluid outlet and configured to transport a sample fluid, and a sensor container fluidically separated from the reference electrode container by a membrane, wherein one side of the membrane faces the reference electrode container and the other side of the membrane faces the fluid channel.

[0085] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, further comprising at least one analyte sensor located in a sensor container that is in fluid communication with a fluid channel.

[0086] An exemplary sensor assembly according to any one of the preceding exemplary embodiments, wherein the membrane comprises at least one pore, and the wicking member is configured to maintain a liquid junction in the membrane when exposed to a reference fluid.

[0087] An exemplary fluid analyzer comprising: a sample receiving assembly having a sample probe having a fluid inlet and a fluid outlet; a fluid waste assembly; and a sensor assembly fluid-communicating with the sample receiving assembly and the fluid waste assembly, wherein the sensor assembly includes: a reference electrode container configured to contain a reference fluid, comprising a reference electrode; a membrane configured to fluid-communicate with the reference electrode container; and a wicking member configured to fluid-communicate with the reference electrode container and configured to draw the reference fluid toward the membrane when the membrane and the wicking member are exposed to the reference fluid.

[0088] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the wicking member is in contact with the membrane.

[0089] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the wicking member comprises a hydrophilic material.

[0090] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the sensor assembly is located within a reference electrode container and further includes a sealing material that is movable from a closed position to an open position, wherein in the closed position the wicking member and membrane are sealed from the reference fluid, and in the open position the wicking member and membrane are exposed to the reference fluid.

[0091] The sealing material is a plug, as described in any one of the preceding exemplary embodiments of the exemplary fluid analyzer.

[0092] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the reference electrode container has a pocket, the plug is fitted into the pocket in a closed position, and the wicking member is located between the plug and the membrane within the pocket.

[0093] The sealing material is a perforable barrier configured to be perforated, as described in the exemplary fluid analyzer according to any one of the preceding exemplary embodiments.

[0094] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the reference electrode container has a pocket, a perforable barrier covers the pocket in a closed position, and a wicking member is positioned between the perforable barrier and the membrane within the pocket.

[0095] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the membrane and / or wicking member is located inside the reference electrode container.

[0096] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the membrane and / or wicking member is located outside the reference electrode container.

[0097] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the first end of the wicking member is located inside the reference electrode container, the second end of the wicking member is located outside the reference electrode container, the second end of the wicking member is in contact with a membrane, and the membrane is located outside the reference electrode container.

[0098] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, further comprising a housing including a reference electrode container and a sensor container fluidically separated from the reference electrode container by a membrane, the sensor assembly having a fluid inlet, a fluid outlet, and a fluid channel extending between the fluid inlet and the fluid outlet and configured to transport a sample fluid, with one side of the membrane facing the reference electrode container and the other side of the membrane facing the fluid channel.

[0099] The sensor assembly further includes at least one analyte sensor located in a sensor container that is in fluid communication with a fluid channel, as described in any one of the preceding exemplary embodiments of the exemplary fluid analyzer.

[0100] An exemplary fluid analyzer according to any one of the preceding exemplary embodiments, wherein the membrane comprises at least one pore, and the wicking member is configured to maintain a liquid junction in the membrane when exposed to a reference fluid.

[0101] An exemplary method for forming a sensor assembly for a body fluid analyzer, comprising: positioning a membrane so as to be fluid-communicable with a reference electrode container configured to include a reference electrode and to include a reference fluid; and positioning a wicking member to draw the reference fluid toward the membrane when the membrane and wicking member are exposed to the reference fluid.

[0102] The exemplary method according to any one of the prior exemplary embodiments, wherein the step of positioning the wicking member further includes bringing the wicking member into contact with the film.

[0103] An exemplary method according to any one of the preceding exemplary embodiments, further comprising sealing the membrane and wicking member from the reference fluid before positioning the reference fluid in the reference electrode container.

[0104] The sealing step further comprises sealing the membrane and wicking member with a plug that is movable from a closed position to an open position, in which case the wicking member and membrane are sealed from the reference fluid, and in the open position the wicking member and membrane are exposed to the reference fluid when the reference electrode container contains the reference fluid, as described in any one of the preceding exemplary embodiments.

[0105] The exemplary method according to any one of the prior exemplary embodiments, further comprising the step of positioning the membrane and wicking member in a pocket of a reference electrode container.

[0106] The sealing step further comprises fitting the plug into a pocket such that the wicking member is positioned between the plug and the membrane within the pocket, as described in any one of the preceding exemplary embodiments of the exemplary method.

[0107] The sealing step further includes sealing the membrane and wicking member with a perforable barrier that is movable from a closed position to an open position, in which case the wicking member and membrane are sealed from the reference fluid, and in the open position the wicking member and membrane are exposed to the reference fluid when the reference electrode container contains the reference fluid, as described in any one of the preceding exemplary embodiments.

[0108] The exemplary method according to any one of the prior exemplary embodiments, further comprising the step of positioning the membrane and wicking member in a pocket of a reference electrode container.

[0109] The sealing step further comprises covering the pocket with a perforable barrier such that the wicking member is positioned between the perforable barrier and the membrane within the pocket, as described in any one of the preceding exemplary embodiments of the exemplary method.

[0110] The exemplary method according to any one of the preceding exemplary embodiments, wherein the membrane and / or wicking member is located inside the reference electrode container.

[0111] The exemplary method according to any one of the preceding exemplary embodiments, wherein the membrane and / or wicking member is located outside the reference electrode container.

[0112] An exemplary method according to any one of the preceding exemplary embodiments, wherein the first end of the wicking member is located inside the reference electrode container, the second end of the wicking member is located outside the reference electrode container, the second end of the wicking member is in contact with a membrane, and the membrane is located outside the reference electrode container.

[0113] An exemplary method according to any one of the preceding exemplary embodiments, wherein the reference electrode container is defined by a housing that further includes a sensor container fluidly separated from the reference electrode container by a membrane, the sensor container having a fluid inlet, a fluid outlet, and a fluid channel extending between the fluid inlet and the fluid outlet and configured to transport a sample fluid, and the step of positioning the membrane in the reference electrode container further includes positioning the membrane such that one side of the membrane faces the reference electrode container and the other side of the membrane faces the fluid channel.

[0114] An exemplary method according to any one of the prior exemplary embodiments, further comprising positioning at least one analyte sensor in a sensor container that is in fluid communication with a fluid channel.

[0115] The exemplary method according to any one of the preceding exemplary embodiments, wherein the step of positioning the membrane further includes a membrane having at least one pore, and the wicking member maintains a liquid junction in the membrane when exposed to a reference fluid.

Claims

1. A sensor assembly for a body fluid analyzer, which includes: A reference electrode container configured to include a reference electrode and contain a reference fluid; A membrane configured to communicate fluidly with the reference electrode container; A wicking member configured to communicate with the reference electrode container and to draw the reference fluid toward the membrane when the membrane and wicking member are exposed to the reference fluid, It includes a sealing material located inside the reference electrode container that can move from a closed state to an open state, In the closed state, the wicking member and membrane are sealed from the reference fluid, and in the open state, the wicking member and membrane are exposed to the reference fluid. The sealing material is a plug. The membrane contains at least one pore, and the wicking member is configured to maintain a liquid junction in the membrane when exposed to a reference fluid. The aforementioned sensor assembly.

2. The sensor assembly according to claim 1, wherein the wicking member is in contact with the membrane.

3. The sensor assembly according to claim 1, wherein the wicking member includes a hydrophilic material.

4. The sensor assembly according to claim 1, wherein the reference electrode container has a pocket, the plug is fitted into the pocket in a closed state, and the wicking member is positioned between the plug and the membrane within the pocket.

5. The sensor assembly according to claim 1, wherein the wicking member is located inside the reference electrode container.

6. The sensor assembly according to claim 1, wherein the wicking member is located outside the reference electrode container.

7. The sensor assembly according to claim 1, wherein the first end of the wicking member is located inside the reference electrode container, the second end of the wicking member is located outside the reference electrode container, and the second end of the wicking member is in contact with the membrane.

8. The housing further includes a reference electrode container and a sensor container, which are fluidically separated from the reference electrode container by a membrane, having a fluid inlet, a fluid outlet, and a fluid channel extending between the fluid inlet and the fluid outlet and configured to transport a sample fluid. The sensor assembly according to claim 1, wherein one side of the membrane faces a reference electrode container and the other side of the membrane faces a fluid flow path.

9. The sensor assembly according to claim 8, further comprising at least one analyte sensor located in a sensor container that is in fluid communication with a fluid channel.

10. It is a fluid analyzer: A sample receiving assembly having a sample probe with a fluid inlet and a fluid outlet; Fluid waste assembly and; The sensor assembly includes a sample receiving assembly and a fluid waste assembly, and the sensor assembly is in fluid communication with the fluid, A reference electrode container configured to include a reference electrode and contain a reference fluid; A membrane configured to communicate fluidly with the reference electrode container; A wicking member configured to communicate with the reference electrode container and to draw the reference fluid toward the membrane when the membrane and wicking member are exposed to the reference fluid: It includes a sealing material located inside the reference electrode container that can move from a closed state to an open state, In the closed state, the wicking member and membrane are sealed from the reference fluid, and in the open state, the wicking member and membrane are exposed to the reference fluid. The sealing material is a plug. The membrane contains at least one pore, and the wicking member is configured to maintain a liquid junction in the membrane when exposed to a reference fluid. The aforementioned fluid analyzer.

11. The fluid analyzer according to claim 10, wherein the wicking member is in contact with the membrane.

12. The fluid analyzer according to claim 10, wherein the wicking member includes a hydrophilic material.

13. The fluid analyzer according to claim 10, wherein the reference electrode container has a pocket, the plug is fitted into the pocket when closed, and the wicking member is positioned between the plug and the membrane within the pocket.

14. The fluid analyzer according to claim 10, wherein the wicking member is located inside the reference electrode container.

15. The fluid analyzer according to claim 10, wherein the wicking member is located outside the reference electrode container.

16. The fluid analyzer according to claim 10, wherein the first end of the wicking member is located inside the reference electrode container, the second end of the wicking member is located outside the reference electrode container, and the second end of the wicking member is in contact with the membrane.

17. The sensor assembly is: The housing further includes a reference electrode container and a sensor container, which are fluidically separated from the reference electrode container by a membrane, having a fluid inlet, a fluid outlet, and a fluid channel extending between the fluid inlet and the fluid outlet and configured to transport a sample fluid. The fluid analyzer according to claim 10, wherein one side of the membrane faces a reference electrode container and the other side of the membrane faces a fluid flow path.

18. The fluid analyzer according to claim 16, further comprising at least one analyte sensor located in a sensor container that is in fluid communication with a fluid channel.

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