Calibration using regenerated surfaces

Abstract

This invention relates to body fluid monitoring. A reagent-free calibration method is proposed to be incorporated into a patch or wearable device. The method involves capturing molecules of interest (i.e., calibration molecules within the patient's biofluid) and releasing these molecules of interest when calibration is required. This eliminates the need for storing onboard reagents. Because calibration is performed within the same biofluid, any matrix effects are corrected for.

Description

Technical Field

[0001] This invention relates to body fluid monitoring, and particularly to a calibration unit, a body fluid monitoring device, and a computer program unit. Background Technology

[0002] Sensors (e.g., biosensors and electrochemical sensors) are known to drift over time and require calibration or recalibration. For electrochemical sensors, drift can be caused by reduced functionality (e.g., enzyme function), inherent drift, or drift due to sensor fouling.

[0003] Typically, calibration is performed using a calibration solution with a known concentration of the molecule of interest. The calibration solution can be stored inside the patch, but this solution can lead to issues with stability, patch design, and reusability. Another approach is to manually apply the calibration solution to the patch, but this solution requires trained personnel to perform the application, increasing the complexity of the calibration process and the likelihood of errors. A third option is to use standardized measurement methods (e.g., central laboratory testing) for calibration; again, this option has the disadvantage of placing an additional burden on the patient, requiring trained personnel, and potentially introducing workflow problems.

[0004] Furthermore, matrix effects are a major problem in the field of biosensors. Matrix effects (i.e., changes in binding conditions caused by interfering components in the biological fluid) are caused by the presence of molecules other than the molecule of interest in the same biological fluid and can lead to overestimation or underestimation of the true detection concentration. Matrix effects vary from patient to patient and are increased when the patient is ill.

[0005] US2019 / 142311 A1 describes an apparatus for calibrating an electrochemical aptamer-based biofluidic sensor. In some embodiments, the calibrator is located near the EAB sensor, and calibration is facilitated by introducing the biofluid into the apparatus. Other embodiments include various mechanisms for introducing the calibration solution into the sensor, including attracting the calibration solution to the sensor by potential, dispensing mechanisms such as inkjet nozzles, and pressure-actuated calibration dispensing. Embodiments employing bifurcated biofluid delivery paths are also included, allowing calibration and biofluid sensing to be performed alternately. Summary of the Invention

[0006] There is a need to improve the calibration of biosensors.

[0007] This invention is defined by the independent claims, wherein further embodiments are included in the dependent claims. It should be noted that the aspects described below also apply to calibration units, body fluid monitoring devices, and computer program units.

[0008] According to a first aspect of the invention, a calibration unit suitable for calibrating a sensor device adapted to detect analyte molecules in a fluid sample of the object is provided. The calibration unit includes a calibration matrix having a trapping surface on which calibration acceptors adapted to reversibly bind analyte molecules in the fluid sample of the object are immobilized. The bound analyte molecules represent calibration molecules that can be used to calibrate the sensor device. The calibration unit further includes a regeneration component configured to regenerate the trapping surface by releasing the calibration molecules from the trapping surface into an aqueous solution to form a calibration liquid for calibrating the sensor device.

[0009] In other words, a reagent-free calibration method is proposed for calibrating sensor devices. This reagent-free calibration method involves capturing analyte molecules (i.e., calibration molecules) within the patient's biological fluid and releasing these analyte molecules (i.e., calibration molecules) when calibration is required. Therefore, this reagent-free calibration method eliminates the need for storing onboard reagents. The proposed calibration unit is useful for any biosensor that uses the calibration method and is in long-term contact with the biological fluid of interest. Examples of biosensors may include, for example, wearable devices, patches, insertable devices, and implantable devices. Examples of biosensors may also include sensor elements within the biological fluid of interest for performing measurements, for example, via a central axis, in interstitial fluid and / or blood.

[0010] To this end, a calibration unit is proposed comprising a calibration matrix having a capture surface on which calibration receptors are immobilized for binding analyte molecules in a fluid sample. Optionally, the calibration unit may be an integral part of a sensor device. The calibration receptor refers to a receptor within the calibration unit. A receptor can refer to any molecule of synthetic or natural origin that has a reasonable affinity and specificity for one or more analyte molecules. The immobilized receptor and analyte molecule may also refer to a bioconjugation pair, which may include a variety of known ligands. For example, those skilled in the art will recognize that a bioconjugation pair may include, for example, antigens or antibodies, hormones or neurotransmitters and receptors, substrates or allosteric effectors and enzymes, lectins and sugars, DNA or RNA structures (e.g., aptamers and their binding substances (including other DNA or RNA substances or binding proteins)), proteins, biotin and adivin or streptavidin systems, enzymes and their substrates and inhibitors, lipid binding systems, and combinations thereof. The binding of the analyte molecule to the receptor forms a receptor-analyte complex. For example, an antibody may be immobilized on the capture surface of the calibration unit, which captures a specific antigen; the antigen is the analyte of interest (i.e., the analyte molecule). Therefore, when a sample comes into contact with a surface, the calibration receptor can bind to the analytes present in the sample.

[0011] Using calibration acceptors, the capture surface of the calibration unit can capture a sufficient amount of analyte molecules. The amount of analyte molecules captured by the capture surface can be controlled by selecting a predetermined amount of calibration acceptors and the type of acceptor molecules on the capture surface. Once a predefined amount of analyte molecules has been captured, they are ready to be used as calibration molecules, which can be released into an aqueous solution (e.g., a buffer solution of the object or a fluid sample) to form a calibration liquid. The reversible nature of analyte binding to the calibration acceptor means that the analyte can, in principle, be released from the calibration acceptor, thereby regenerating the sensor surface to form a calibration liquid and allowing for the reuse of the calibration area.

[0012] To regenerate the captured surface, the calibration unit also includes a regeneration component. Three examples of the regeneration component will be briefly described below.

[0013] A first example of a regeneration assembly is based on the understanding that electrolysis of an aqueous medium can be used to regenerate a captured surface. To this end, a regeneration assembly is proposed comprising an electrolytic component for electrolyzing an aqueous solution (e.g., a fluid sample or buffer solution). Pairs of multiple spatially separated conductive regions across the surface provide a voltage (e.g., a voltage distribution); the corresponding conductive region of each pair thus becomes an anode and a cathode. The voltage is sufficient to electrolyze the aqueous medium, thereby causing the generation of hydrogen ions at the anode and hydroxide ions at the cathode. Therefore, the local pH at the anode decreases, and the local pH at the cathode increases. These local pH changes can cause the receptor-analyte complex to be disrupted (e.g., denatured), in order to regenerate at least a portion of the captured surface.

[0014] A second example of a regeneration assembly is based on the understanding that a potential can be generated in response to fluid flow through a calibration unit. To this end, a regeneration assembly is proposed that may include: a flow channel arranged such that fluid flows through the flow channel; and a sensing electrode (or array) arranged circumferentially around the periphery of the flow channel. The sensing electrode (or array) can generate a triboelectric potential due to the mobile ions in the fluid flowing through the flow channel. The triboelectric potential generated by the sensing electrode can correspond to the rate of the mobile ions in the fluid flowing through the flow channel, more specifically to the velocity and concentration (i.e., flow rate and concentration rate) of the mobile ions in the fluid flowing through the flow channel. The ions moving through the flow channel can interact with the sensing electrode to induce a triboelectric potential (voltage), which can be directly used as a current for regenerating the captured surface. Alternatively or additionally, the calibration unit may include: a flow channel arranged such that fluid flows through the flow channel; and one or more ion-selective electrodes arranged inside the flow channel. The ion-selective electrodes can generate an electrochemical potential due to the mobile ions in the fluid flowing through the flow channel. The electrochemical potential generated by the ion-selective electrode can correspond to the rate or concentration of (specific) mobile ions in the fluid flowing through the flow channel. The ions moving through the flow channel can interact with the ion-selective electrode to induce an electrochemical potential (voltage), which can be directly used as the current for regenerating the capture surface.

[0015] A third example of the regeneration component is based on the understanding that the initial pH of the droplets of a fluid sample (e.g., sweat, sebum, and interstitial fluid) excreted on the skin surface is initially around 2, in which case the acidity of sweat, sebum, and interstitial fluid is sufficient to support the release of calibrator molecules from the capture surface. For example, in the case of sweat droplets, the pH gradually increases with the rate of sweating until it reaches a near-neutral pH, i.e., pH ~ 7. This occurs due to the inverse relationship between the ion reabsorption flux along the sweat ducts and the rate of sweating. Therefore, the initial portion of one or more sweat droplets forming on the skin surface from active sweat glands will have a pH of 2, and only this initial portion is used to release analyte molecules. For this purpose, the regeneration component can have a chamber for collecting the fluid sample from the skin via an inlet. The chamber also has an outlet, which is arranged, for example, in size, such that once the chamber is filled, droplets of the fluid sample protrude from the outlet. A fluid delivery component releases the droplet fluid sample from the outlet and delivers the released droplets toward the sensor. As droplets are delivered toward the sensor, the fluid delivery assembly maintains the droplets in a discrete form. Because the delivery of the released droplets is at least as fast as, and preferably faster than, the protrusion of subsequent droplets of the fluid sample from the outlet, a droplet-by-droplet supply is provided to the sensor. This prevents such subsequent sweat droplets from protruding and merging with the released sweat droplets being delivered to the sensor in the process. Specifically, the first portion of one or more droplets of a fluid sample (e.g., sweat, sebum, and interstitial fluid) present on a skin surface at pH 2 is delivered to the capture surface by means of an electromechanical (e.g., electrowetting) or chemical gradient. These localized pH changes cause disruption (e.g., denaturation) of the receptor-analyte complex, thereby regenerating at least a portion of the capture surface.

[0016] In one example, the calibration unit can be located in the same delivery channel as the sensor device. In another example, the calibration unit can be located in a different delivery channel than the sensor device. In this example, the capture zone of the calibration unit can be pre-loaded, and liquid can be removed from the capture zone using a capillary pump and an evaporator, making the calibration molecules less prone to degradation. When calibration is required, the valve and the regeneration assembly are configured to release the calibration molecules.

[0017] Typically, calibration is performed using a calibration curve / range. In the example, the sensor is calibrated by creating a calibration curve through integrating multiple capture regions into a calibration unit and releasing them at different time intervals. The time-separated release of calibration molecules can be accomplished by:

[0018] (1) Activate the regeneration zone at different time intervals to obtain different concentrations;

[0019] (2) It has multiple bands with different numbers of receptors (i.e., the size of the capture region), thus providing different concentrations after release; and / or

[0020] (3) Possesses receptors that release at different pH values. By binding a mixture of these receptor types, a specific concentration can be triggered by activating the same regeneration zone under different pH conditions. Note that antibodies can be designed to have different K values ​​depending on the pH condition. off .

[0021] According to an embodiment of the present invention, the aqueous solution is a fluid sample of the object.

[0022] Because the calibration molecules are in the same matrix (i.e., the biological fluid) during measurement, matrix effects (i.e., changes in binding conditions due to interfering components in the biological fluid) are also corrected. The standard calibration fluid is a buffer solution, and by definition, it is not the same fluid as the biological fluid (i.e., the fluid sample of the same object).

[0023] According to an embodiment of the invention, the regeneration component is configured to apply a potential to the capture surface to release the calibration molecule from the capture surface.

[0024] According to an embodiment of the present invention, the regeneration assembly includes an electrolysis assembly configured to electrolyze the aqueous solution.

[0025] In this example, the regeneration assembly is based on the understanding that water electrolysis can be used to regenerate surfaces to, for example, eliminate or minimize the need for reagents to achieve regeneration. The proposed regeneration assembly includes an electrolysis unit for electrolyzing an aqueous medium. A voltage is applied to at least two of a plurality of spatially separated conductive regions across the surface; these at least two conductive regions thus become the anode and cathode. The voltage is sufficient to electrolyze water, causing the generation of hydrogen ions at the anode and hydroxide ions at the cathode. Consequently, the local pH at the anode decreases, and the local pH at the cathode increases. These local pH changes can cause the acceptor-analyte complex to be disrupted (e.g., denatured), thereby regenerating at least a portion of the surface.

[0026] According to an embodiment of the present invention, the electrolysis assembly includes: at least three spatially separated conductive regions on the capture surface; and a power source. The power source is configured to implement a first setting and a second setting, wherein in the first setting, a first pair of combinations across the at least three conductive regions provides a voltage sufficient for electrolyzing the aqueous solution received on the capture surface, and in the second setting, a second pair of combinations across the at least three conductive regions provides a voltage sufficient for electrolyzing the aqueous solution received on the capture surface, the second pair of combinations being different from the first pair of combinations.

[0027] The pairs can differ from each other, for example, in the spacing between the conductive regions and the arrangement of the voltage polarity applied to the (alternating) conductive regions.

[0028] The voltage can differ between the first and second configurations. For example, the voltage in the second configuration can be higher or linearly increased compared to the first configuration. Alternatively or additionally, the second pair of conductive regions can be spaced further apart on the surface compared to the first pair of conductive regions. These measures can help improve the degree of electrolytic regeneration of the captured surface.

[0029] Conductive regions can be arranged relative to each other in an interdigitated configuration (e.g., a planar interdigitated configuration). The interdigitated configuration can be advantageous in relatively large areas (e.g., within a few millimeters). 2 up to cm 2 A voltage can be provided over an area (on the order of magnitude of) and can also be provided locally on a surface, where regeneration is driven by localized pH changes caused by water electrolysis. A similar effect can be achieved using conductive regions, for example, arranged as multiple concentric ring sections.

[0030] Multiple spatially separated conductive regions can comprise an array of conductive regions, wherein the spacing between adjacent conductive regions alternates between larger and smaller spacings. A power source can be configured to supply voltage across adjacent conductive regions separated by larger spacings, while adjacent conductive regions separated by smaller spacings have the same polarity. Such an arrangement can help reduce the areas on the surface where electrolytic regeneration does not occur. Therefore, the degree of electrolytic regeneration on the surface can be improved.

[0031] Multiple spatially separated conductive regions may comprise a grid of conductive strips. The power supply is configured to implement: a first mode in which voltage (distribution) is supplied across parallel strips extending in a first direction; and a second mode in which voltage is supplied across parallel bars extending in a second direction, different from the first direction. The power supply can, for example, be configured to implement the first and second modes sequentially. This allows for more complete surface regeneration.

[0032] The power supply can be configured to switch the voltage polarity across at least two conductive regions. For example, certain receptor-analyte (e.g., antibody-antigen) complexes may denature only at an optimal acidic or alkaline pH, while being robust to large pH changes in other conditions. For this reason, the power supply can be configured to switch the voltage polarity across the respective conductive regions, or to superimpose a larger AC voltage onto a DC voltage to switch the polarity of the electrodes and the direction of the electric field. This polarity switching induces the regeneration of trapped material located near the two respective conductive regions.

[0033] According to an embodiment of the invention, the calibration unit further includes a component comprising a flow channel arranged such that the aqueous solution flows through the flow channel. The component also includes an electrode arrangement comprising a sensing electrode and / or an ion-selective electrode. The sensing electrode is arranged circumferentially around the periphery of the flow channel and configured to generate a triboelectric potential in response to moving ions in the aqueous solution flowing through the flow channel. The ion-selective electrode is arranged inside the flow channel and configured to generate an electrochemical potential in response to moving ions in the aqueous solution flowing through the flow channel.

[0034] In other words, the calibration unit can directly generate a potential based on the detected fluid. That is, detecting fluid can generate a voltage, which can be used to trigger the activation of the regeneration components or directly as a current for the regenerable capture surface of the calibration unit.

[0035] A first example of this component may include: a flow channel arranged such that fluid flows through it; and a sensing electrode (or array) arranged circumferentially around the periphery of the flow channel. The sensing electrode (or array) can generate a triboelectric potential due to the moving ions in the fluid flowing through the flow channel. The triboelectric potential generated by the sensing electrode can correspond to the rate of movement of the moving ions in the fluid flowing through the flow channel, more specifically to the velocity and concentration (flow rate and concentration rate) of the moving ions in the fluid flowing through the flow channel. Ions moving through the flow channel can interact with the sensing electrode to induce a triboelectric potential (voltage).

[0036] The sensing electrodes can be arranged in series, for example, as circumferential elements / arrays of flow channels, such that if multiple sensing electrodes are provided, fluid flows between a pair of sensing electrodes. The sensing electrodes can be measured relative to ground. Preferably, at least two sensing electrodes are provided: a positive electrode and a ground electrode or reference electrode. The triboelectric potential generated at the sensing electrodes can correspond to the difference between the two electrodes and can provide a passive trigger for calibrating molecular release.

[0037] A second instance of the component may include: a flow channel arranged such that fluid flows through it; and one or more ion-selective electrodes disposed within the flow channel. The ion-selective electrodes can generate an electrochemical potential due to the mobile ions in the fluid flowing through the flow channel. The electrochemical potential generated by the ion-selective electrodes may correspond to the rate or concentration of (specific) mobile ions in the fluid flowing through the flow channel. Ions moving through the flow channel can interact with the ion-selective electrodes to induce an electrochemical potential (i.e., a voltage).

[0038] An ion-selective electrode and a reference electrode can be arranged (e.g., concentrically) in a flow channel such that fluid flows around the reference electrode. Preferably, at least two ion-selective electrodes are provided: a positive electrode and a ground electrode or reference electrode. The signal generated by the ion-selective electrode can be measured relative to the potential on the reference electrode. Fluid can flow through the ion-selective membrane electrode, and the electrode can be equivalent to a pH measurement probe using a reference potential / solution potential.

[0039] According to an embodiment of the invention, the component is (i) a regeneration component configured to apply at least one of the triboelectric potential and the electrochemical potential to the trapping surface to release the calibration molecule from the trapping surface; or (ii) a triggering component configured to trigger activation of the regeneration component when at least one of the generated triboelectric potential and the generated electrochemical potential exceeds a predetermined threshold corresponding to a given ion migration rate.

[0040] In other words, the liquid triboelectric potential or electrochemical potential generated by the instantaneous or pulsating sweat waves (moving ions) of the microfluidic system can be used to trigger the activation of regenerative components or directly as a current for regenerative capture surfaces.

[0041] According to an embodiment of the invention, the regeneration assembly includes a fluid collection assembly comprising a chamber having an inlet and an outlet. The inlet is for receiving droplets of a fluid sample excreted onto a skin surface, and the outlet is arranged such that, after the chamber is filled with the fluid sample, droplets of the fluid sample form and protrude from the outlet. The regeneration assembly further includes a fluid delivery assembly arranged to release droplets protruding from the outlet and deliver the released droplets to the calibration matrix, thereby enabling the outlet to be used for the formation of subsequent droplets and to protrude from the outlet upon further filling of the chamber. The fluid delivery assembly is arranged to deliver the released droplets at least as quickly as the subsequent droplets protruding from the outlet, such that the individual droplets do not contact each other. The fluid delivery assembly is configured to deliver one or more droplets initially excreted onto the skin surface to the calibration matrix to release the calibration molecules from the capture surface, thereby forming the calibration liquid.

[0042] In this example, the regeneration component is based on the understanding that collecting fluid samples (e.g., sweat, sebum, and interstitial fluid) excreted on the skin surface and supplying them to the calibration unit as discrete droplets is advantageous compared to methods using continuously flowing fluid samples. This discrete approach allows (e.g., by means of electromechanical or chemical gradients) the delivery of a first portion of one or more droplets of the fluid sample emerging from the skin surface to the capture surface of the calibration unit. Since the pH of the first portion of one or more droplets is initially around 2, the first portion of one or more droplets may cause early disruption (e.g., denaturation) of the receptor-analyte complex, thereby regenerating at least a portion of the capture surface.

[0043] According to an embodiment of the present invention, the calibration matrix is ​​configured to release different amounts of calibration molecules into the aqueous solution to form calibration liquids with different concentrations, thereby constructing calibration curves to calibrate the sensor device.

[0044] According to embodiments of the present invention, calibration liquids with different concentrations are formed by at least one of the following: activating the regeneration component at different time intervals to release the calibration molecules from the capture surface, thereby producing different concentrations; providing a plurality of capture zones, each of the plurality of capture zones having a different amount of calibration receptors, such that each capture zone releases a different amount of calibration molecules; and having different types of calibration receptors, each of the different types of calibration receptors being configured to release the calibration molecules with a different amount of hydrogen ions.

[0045] According to an embodiment of the invention, the calibration unit further includes a capillary pump configured to remove fluid from the capture zone and an evaporator configured to evaporate the removed fluid.

[0046] In this example, the capture zone of the calibration unit can be arranged in a different delivery channel than the sensor device. The capture zone of the calibration unit can be pre-loaded, and liquid can be removed from the capture zone using a capillary pump and evaporator, making the calibration molecules less prone to degradation. When calibration is required, the valve and regeneration assembly are configured to release the calibration molecules.

[0047] According to a second aspect of the invention, a body fluid monitoring device is provided for detecting an analyte in a fluid sample of a subject. The body fluid monitoring device includes: a calibration unit according to the first aspect and any associated examples; a sensor device having a capture surface on which sensor molecules are fixed for detecting the analyte in the fluid sample, wherein the sensor device is in fluid communication with the calibration unit at least during a calibration event; and a fluid collection assembly for supplying the fluid sample to the calibration unit and the sensor device.

[0048] According to an embodiment of the present invention, the body fluid monitoring device further includes a delivery channel arranged to accommodate the calibration unit and the sensor device. Alternatively, the body fluid monitoring device further includes two delivery channels and a valve arrangement, the two delivery channels being arranged to accommodate the calibration unit and the sensor device respectively, and the valve arrangement being configured to control the flow of fluid between the two delivery channels.

[0049] According to a third aspect of the present invention, a method for calibrating a sensor device for detecting an analyte in a fluid sample of a subject is provided, the method comprising the following steps:

[0050] a) Receive a fluid sample of the object using a calibration unit;

[0051] The calibration unit includes a calibration matrix having a capture surface on which a calibration acceptor is fixed.

[0052] b) Reversibly binds a known amount of analyte molecules in the fluid sample of the object using the calibration receptor, wherein the bound analyte molecules represent calibration molecules that can be used to calibrate the sensor device; and

[0053] c) The capture surface is regenerated using a regeneration assembly by releasing the calibration molecules from the capture surface into an aqueous solution to form a calibration liquid; and

[0054] d) Deliver the released calibration molecules to the sensor device for calibration of the sensor device.

[0055] According to another aspect of the invention, a program unit for calibrating a sensor for detecting analytes in a fluid sample of an object is provided, the program unit being adapted, when run by a processor, to execute the method according to the third aspect and any associated examples.

[0056] Advantageously, the benefits provided by any one of the above aspects apply equally to all other aspects, and vice versa.

[0057] In the detailed description of this disclosure, those skilled in the art will note that directional terms (e.g., "above," "below," "upper," "lower," and other similar terms) are used for the convenience of the reader in referring to the accompanying drawings. Furthermore, those skilled in the art will note that the description may include other terms conveying position, orientation, and direction without departing from the principles of this disclosure.

[0058] When any form of fluid sample (e.g., droplets or continuum, whether moving or stationary) is described as being “on,” “at,” or “above” an electrode, array, matrix, or surface, such fluid may be in direct contact with the electrode / array / matrix / surface, or may be in contact with one or more layers or films interposed between the liquid and the electrode / array / matrix / surface.

[0059] Furthermore, in this detailed description, those skilled in the art should note that quantitatively qualifying terms (e.g., "usually," "basically," "most," and other terms) are generally used to mean that the object, characteristic, or quality in question constitutes the majority of the reference object. The meaning of any of these terms depends on the context in which they are used and may be explicitly modified.

[0060] The term "controller" is generally used to describe various means associated with the operation of a flow probe device, system, or method. A controller can be implemented in a variety of ways (e.g., using dedicated hardware) to perform the various functions discussed herein. A "processor" is an example of a controller using one or more microprocessors, which can be programmed using software (e.g., microcode) to perform the various functions discussed herein. A controller can be implemented with or without a processor, and can also be implemented as a combination of dedicated hardware performing some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) performing other functions. Examples of controller components that can be used in various embodiments of this disclosure include, but are not limited to, conventional microprocessors, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs). These and other aspects of the invention will become apparent and elucidated with reference to the embodiments described below.

[0061] In various implementations, the processor or controller may be associated with one or more storage media (collectively referred to herein as "memory," e.g., volatile and non-volatile computer memory). In some implementations, the storage media may be encoded with one or more programs that, when run on one or more processors and / or controllers, perform at least some of the functions discussed herein. The various storage media may be fixed within the processor or controller, or may be portable, such that one or more programs stored thereon can be loaded into the processor or controller to implement various aspects of this disclosure discussed herein. The term "program" or "computer program" is used herein in a general sense to refer to any type of computer code (e.g., software or microcode) capable of being used to program one or more processors or controllers.

[0062] It should be understood that all combinations of the foregoing concepts and the additional concepts discussed in more detail below (assuming these concepts are not contradictory) are considered part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter appearing at the end of this disclosure are considered part of the inventive subject matter disclosed herein.

[0063] These and other aspects of the invention will become apparent and will be elucidated with reference to one or more embodiments described below. Attached Figure Description

[0064] In the accompanying drawings, the same reference numerals generally refer to the same parts throughout the different views. Furthermore, the drawings are not necessarily drawn to scale; rather, the emphasis is usually on illustrating the principles of the invention.

[0065] Figure 1 An example of a calibration unit is illustrated schematically.

[0066] Figure 2 The flowchart of the calibration method is shown in the figure.

[0067] Figure 3 A more detailed schematic diagram is provided. Figure 2 The calibration method.

[0068] Figure 4 An example of a regeneration component is illustrated schematically.

[0069] Figure 5 An exemplary regeneration of the capture surface of the calibration unit is schematically illustrated.

[0070] Figure 6 An exemplary fork guide area is schematically shown.

[0071] Figure 7 Another exemplary fork-guided electrical area is schematically shown.

[0072] Figure 8 Another example of a regeneration component is illustrated schematically.

[0073] Figure 9 A cross-section of an exemplary sensing electrode is schematically illustrated.

[0074] Figure 10 The sweating rate and pH value are shown during 60 minutes of effort at a self-selected pace.

[0075] Figure 11 Another example of a regeneration component is illustrated schematically.

[0076] Figure 12 An example of a body fluid monitoring device is shown schematically.

[0077] Figure 13 Another example of a body fluid monitoring device is illustrated schematically. Detailed Implementation

[0078] Figure 1 An example of calibration unit 10 is schematically illustrated. Calibration unit 10 includes calibration matrix 12 and regeneration component 20.

[0079] The calibration matrix 12 has a capture surface 14 on which calibration acceptors 16 are immobilized for binding known amounts of analyte molecules 18 in a target fluid sample. The target fluid sample may also be referred to as a biological fluid, which may include, for example, sweat, sebum, interstitial fluid, blood, urine, or saliva. The bound analyte molecules represent calibration molecules that can be used to calibrate the sensor device.

[0080] The calibration receptor 16 can be selected based on the specific analyte molecule 18 that the sensor device wants to sense. The relevant analyte molecule 18 can include, but is not limited to, small molecule compounds, such as compounds with a molecular weight of less than 900 g / mol, such as urea, creatinine, cholesterol, triglycerides, steroid hormones, such as cortisol, glucose, and melatonin.

[0081] The calibration receptor 16 can be selected to bind other molecular types, such as peptides and proteins. For proteins, the calibration receptor 16 can reversibly bind via a protein epitope, for which the calibration receptor 16 includes a suitable binding site. For example, the calibration receptor 16 can be selected to bind cytokines such as IL-1α, IL-1β, IL-6, TNF-α, IL-8, and TGF-βIL-6, and cysteine ​​proteases. For example, protein binding can enable relatively large biomarkers (such as viruses) to bind to the capture surface 14 and be detected. This is particularly relevant to calibrating sensor devices used for sweat sensing, as certain viruses (such as hepatitis C virus) may replicate in sweat glands and be released in sweat.

[0082] The calibration receptor 16 may include, for example, an aptamer, which is an oligonucleotide or peptide molecule that binds to a specific target molecule. As with antibodies, they depend on their three-dimensional conformation to achieve the necessary affinity for the analyte molecule 18.

[0083] In other examples, the calibration receptor 16 may include a molecularly imprinted polymer, which is a polymer imprinted with an antigen or a portion of an antigen. Such a material may contain cavities having a three-dimensional configuration complementary to the three-dimensional shape of the antigen, thereby obtaining the necessary "lock-and-key" structure. The molecularly imprinted polymer may alter its structure due to changes in pH. One example is a pH-sensitive pantoprazole imprinted polymer, known to bind or release the drug according to pH.

[0084] The calibration acceptor 16 can be attached to the capture surface 14 in any suitable manner. In a non-limiting example, a suitable thiol linker can be used to bind the calibration acceptor to the capture surface 14 of the gold surface; the linker is grafted to the capture surface 14 via a sulfur-gold interaction, and the calibration acceptor 16 is grafted (e.g., covalently bonded) to the linker. Various alternatives for attaching the calibration acceptor 16 to the capture surface 14 will be apparent to those skilled in the art.

[0085] In a non-limiting example, analyte molecule 18 may include an antigen, and the calibration receptor may include an antibody. For example, immunoglobulin (IgG) may be a suitable antibody for immobilization on the capture surface 14. IgG is the most common type of antibody in the human circulatory system. Antibodies can be used to capture a variety of molecules. Antibody structures typically contain a constant region (Fc) and an antigen-binding region (Fab), but other forms may also be used, such as containing only a Fab portion or a portion of the Fab portion. Antigens may include, for example, proteins and polysaccharides. Antibodies are known to consist of proteins generated to fight invading foreign species such as viruses. So-called “lock-and-key” interactions selectively bind antigens to antibodies. The strength of the binding between an antibody and an antigen is called “affinity.” Affinity corresponds to the sum of attractive and repulsive forces between the antigen and antibody at the antibody-associated binding site. The attractiveness is determined at least in part by the number of attractive antigen-antibody interactions at the binding site. Non-covalent interactions between antibodies and antigens (such as hydrogen bonds, electrostatic interactions, van der Waals forces, and hydrophobic interactions) may mean that the binding of the antigen to the antibody is reversible. Therefore, adjusting the charge and / or conformation of the antibody may result in a reduction in the number of attractive antigen-antibody interactions. Furthermore, the sum of the repulsive forces can increase, for example, due to changes in the net charge of the antibody and antigen, respectively. Therefore, the "cooperation" between the antigen and antibody can be disrupted by such an adjustment, thereby releasing the antigen from the antibody.

[0086] The regeneration component 20 is configured to regenerate the capture surface 14 by releasing calibration molecules (i.e., bound analyte molecules) from the capture surface 14 into an aqueous solution (e.g., a buffer solution or a biological fluid) to form a calibration fluid for calibrating the sensor device. Exemplary regeneration components will be discussed below, particularly with reference to... Figures 4 to 11 .

[0087] Optionally, the aqueous solution can be a fluid sample of the object. In other words, the calibration molecules and the measurement molecules are in the same matrix (i.e., the biological fluid). Therefore, matrix effects, i.e., changes in binding conditions due to interfering components in the biological fluid, can also be corrected. Normal calibration fluids are buffer solutions and, by definition, are different liquids from the biological fluid (i.e., the fluid sample of the object).

[0088] Figure 2 A flowchart of calibration method 300 is shown, which is in Figure 3 A to Figure 3 It is described in more detail in D.

[0089] In step 310 (i.e., step a), the calibration unit 10 receives a fluid sample of the object. The calibration unit 10 includes a calibration matrix 12 having a capture surface 14 on which a calibration acceptor 16 is fixed.

[0090] exist Figure 3 Step a) is shown in more detail below. Note that this step involves exposing the capture region 14 of the calibration unit 10 with the same biological fluid (e.g., through recycling) as the biological fluid used for the sensor device 60. The sensor device 60 includes a capture surface 62 on which sensor molecules 64 are immobilized. The sensor molecule 64 may be a receptor for binding analyte molecules or enzymes to facilitate the conversion of the analyte into a product. In this example, the calibration receptor 16 and the sensor molecule 64 include different receptors represented by different shapes. In some other examples (not shown), the calibration receptor 16 and the sensor molecule 64 may include the same receptor.

[0091] Go to Figure 2 In step 320 (i.e., step b), the calibration receptor 16 binds to a known amount of analyte molecule 18 in the fluid sample of the target. The bound analyte molecule represents a calibration molecule that can be used to calibrate the sensor device.

[0092] exist Figure 3 Step b) is shown in more detail below. In this step, a sufficient amount of the molecule of interest (i.e., analyte molecule 18) is captured by the calibration acceptor 16. The molecule of interest is the same molecule detected by the sensor device 60. The total amount of analyte molecule 18 captured by the calibration acceptor 16 is driven by the Langmuir equation, which will be briefly described below.

[0093] The reaction between the analyte and the acceptor can be described by the law of mass action, where component A is a constant and component B is a variable:

[0094]

[0095] When components A and B are mixed, they form product AB. This is called the association stage. Moving to the left, components A and B are formed from product AB; this is called dissociation. The total concentration of A (where, [A]) T T represents the total concentration) and its distribution between free A and A in the AB complex. The concentration of the complex [AB] is determined by the Langmuir equation:

[0096]

[0097] Among them, K on It is the association constant and drives the binding of the molecule of interest (B) to the receptor (A), K off It is the dissociation constant and drives the release of the molecule of interest (B) from the receptor (A). Note that the receptor's conformation changes as the pH value changes, K on and L off Changes occur, allowing for the rapid release of molecules. The reaction time (t) (also known as the incubation time) should be long enough for the reaction to reach equilibrium. Therefore, assuming the reaction is in equilibrium, the captured molecular weight can be controlled by selecting predetermined amounts of receptors (the concentration of A) and molecule types (association and dissociation) on specific regions.

[0098] When a predetermined amount of analyte molecules 18 are captured, it is ready to be used as a calibration solution when the conditions of Equation 1 are met. This is the time it takes for the analyte molecules to come into contact with the capture zone. However, Equation 1 is only valid if the fluid is not depleted, therefore the fluid needs to be replenished and needs to flow over the capture surface.

[0099] Go to Figure 2 In step 330 (i.e., step c), the regeneration component 20 regenerates the capture surface 14 by releasing calibration molecules from the capture surface 14 into an aqueous solution to form a calibration liquid for calibrating the sensor device.

[0100] exist Figure 3 Step c) is shown in more detail, illustrating the release of calibration molecules (i.e., bound analyte molecules) upon activation of the regeneration assembly. In this example, the regeneration assembly includes an electrode that is activated to induce water electrolysis. The localized pH change caused by water electrolysis has resulted in the release of bound analyte molecule 18 (i.e., calibration molecules). (Refer to...) Figures 4 to 7 This example will be described in more detail. Other examples of regenerated components will be described below, in particular, with reference to [reference needed]. Figures 8 to 11 As described.

[0101] The release of calibration molecules can be triggered by the need for calibration. Several reasons can cause this, including: gradual chemical degradation of the sensor device, drift associated with electronic components, changes in environmental conditions (e.g., higher or lower temperatures and humidity), changes in atmospheric pressure, exposure to relatively high concentrations of the target analyte of interest, harsh storage and operating conditions (e.g., when the sensor device is dropped or impacted against a hard surface or immersed in a fluid), and manufacturing differences between different sensors. Calibration can also be triggered by contextual and / or clinical reasons. For example, if a measurement deviates from the normal reference range, it can trigger calibration to verify that sensor drift is not the cause.

[0102] Go to Figure 2In step 340 (i.e. step d), the released calibration molecules are delivered to sensor device 60.

[0103] exist Figure 3 Step d) is shown in more detail below. Sensor device 60 measures a known volume of calibration molecules. The values ​​derived from sensor device 60 are used to calibrate sensor device 60.

[0104] For example, calibration itself can be accomplished by comparing the known concentration of the molecule of interest (in this case, from the “capture zone”) with the signal response. When the captured biomarker is released, the sensed concentration x(t) (i.e., the concentration of the biomarker in the patient fluid as a function of time t) is supplemented with C, where C is the known concentration. Therefore;

[0105] Calibration signal = x(t) + C (3)

[0106] At the calibration time, x(t) is still approximately equal to the concentration of the biomarker before the molecule is released (i.e., x(t-1)). Therefore, we can measure the contribution of C to the signal.

[0107] Typically, calibration is performed using a calibration curve / range. Alternatively, the sensor can be calibrated by creating a calibration curve that integrates multiple capture regions and releases them at different time intervals. The time-separated release of calibration molecules can be achieved through at least one of the following methods:

[0108] (1) The regeneration zone is activated at different time intervals, thereby producing different concentrations, as shown in Equation 2;

[0109] (2) By making multiple regions have different amounts of receptors (i.e., the size of the capture region), different concentrations are provided after release; and

[0110] (3) By using receptors that release at different pH values. By incorporating a mixture of these antibody types, a specific concentration can be triggered by activating the same regeneration region under different pH conditions. Note that antibodies can be engineered to have different K values ​​that are pH-dependent. off .

[0111] The following sections will describe three examples of regenerated components in more detail.

[0112] A first example of a regeneration assembly is the understanding that electrolysis of an aqueous medium can be used to regenerate a captured surface. For this purpose, the regeneration assembly includes an electrolysis component for electrolyzing an aqueous solution, such as a fluid sample or buffer solution. Pairs of multiple spatially separated conductive regions across the surface provide a voltage, such as a voltage distribution; the corresponding conductive regions of each pair thus become an anode and a cathode. The voltage is sufficient to electrolyze the aqueous medium, causing the generation of hydrogen ions at the anode and hydroxide ions at the cathode. Therefore, the local pH at the anode decreases, and the local pH at the cathode increases. These local pH changes can cause the receptor-analyte complex to be disrupted (e.g., denatured), thereby regenerating at least a portion of the captured surface.

[0113] Figure 4 The figure illustrates an exemplary electrolytic assembly 20a. Electrolytic assembly 22a includes a plurality of spatially separated conductive regions 22 on a trapping surface 14. The conductive regions 22 are spaced apart by a pitch 24. The pitch 24 can be, for example, in the range of 0.1 mm to 3 mm, such as approximately 1.5 mm. The trapping surface 14 patterned with the conductive regions 22 can be manufactured using any suitable technique. Suitable patterning methods are known, for example, from the fields of printed electronics, thin-film technology, laser ablation, etc.

[0114] The electrolysis assembly 20a may also include a power source 26 for providing voltage across at least two conductive regions 22; the latter thus constitute the anode 28 and the cathode 30. The voltage may be a DC voltage sufficient to electrolyze water contained in the aqueous solution received on the capture surface 14. (See reference...) Figure 5 The regeneration of the capture surface 14 using the electrolysis component 20a is described in more detail.

[0115] Figure 5 The regeneration of the capture surface 14 of the calibration unit 10 is schematically depicted. The capture surface 14 may become saturated when all the calibration acceptors 16 have recombinated with the analyte molecules 18. The bound analyte molecules 18 represent calibration molecules.

[0116] exist Figure 5 The regeneration process of the capture surface 14 is depicted from left to right along the direction of arrow 32. Conductive regions 22 are provided on surface 14, which constitute electrodes 28 and 30 when a voltage is applied to them by a power source 26. When the sample contacts the capture surface 14, this DC voltage is sufficient to electrolyze the water contained in the aqueous medium of the sample.

[0117] For example, in the case of sweat samples, an aqueous medium can correspond to a diluted sodium chloride solution. The physiological sodium chloride concentration in sweat can be approximately 50 mmol / L (compared to 140 mmol / L in plasma). A typical sodium chloride concentration used in buffer solutions is 0.9 wt.%. Electrolysis of this dilute sodium chloride solution approximates the electrolysis of water: oxygen is generated at anode 28, and hydrogen is generated at cathode 30. It is known that electrolyzing higher concentrations of sodium chloride solution will cause chlorine gas to be generated at anode 28. Some of the gases formed can be reabsorbed or eliminated from the system through the vent. When another donor ion (Na₂) is present... + Cl - When the sodium chloride concentration is high, oxygen is typically not generated. Hydrogen will be absorbed by sweat or converted into nanobubbles. Since the formed bubbles may be reabsorbed or are too small to interfere with any microfluidic flow, they may not interfere with the operation of the sensor (especially since electrolysis is used to regenerate the sensor) – that is, biomarker measurements may occur some time after the small amount of gas generated during electrolysis has been reabsorbed / dissolved in the aqueous medium (sweat).

[0118] According to Nernst, under standard conditions, i.e., at standard temperature (273.15 K), water electrolysis is carried out at a voltage greater than approximately 1.23 V, and standard water electrolysis can result in transient hydrogen ion (H+) ions. + ) and hydroxide ions (OH) - Ion concentration gradient pressure (100 kPa, 1 bar). In one embodiment, the voltage across electrodes 28 and 30 can be, for example, in the range of 3 to 4.5 V.

[0119] like Figure 5 As shown in the middle pane, water electrolysis can cause the formation of transient hydrogen ions (H+) between the anode 28 and the cathode 30. + ) and hydroxide ions (OH) - Ion concentration gradient. A localized acidic region near the anode 28 can cause bound analyte molecules 18 (i.e., calibration molecules) to be released from the calibration acceptor 16 in the acidic region. Alternatively or additionally, a localized alkaline region near the cathode 30 can cause analyte molecules 18 (i.e., calibration molecules) to be released from the calibration acceptor 16 in the alkaline region.

[0120] Whether the binding between the calibration receptor 16 and the bound analyte molecule 18 (i.e., the calibration molecule) is disrupted by the more acidic and / or alkaline pH generated by water electrolysis may depend, for example, on the nature of the binding site. The preferred pH for antibody-antigen complex denaturation can be in an acidic range (e.g., in the pH range of 2 to 3), but denaturation can also occur under alkaline conditions. For example, local pH changes can drive conformational changes in the calibration receptor 18. For instance, when the calibration receptor 18 comprises an antibody, a local pH change can trigger the unfolding of the secondary or tertiary structure of the antibody protein.

[0121] To reduce the risk of localized accumulation of undesirable high concentrations of analyte 18 during the regeneration of the capture surface 14, a gradual change in pH can be achieved by gradually increasing the voltage. In an alternative embodiment, the voltage can be applied in relatively short pulses or bursts, which may be preferred for inducing localized pH changes during the regeneration of the capture surface 14, provided the pulse can be safely implemented.

[0122] Once the local pH change caused by water electrolysis has caused the bound analyte molecules 18 (i.e., calibration molecules) to be released from the calibration acceptor 16, the calibration acceptor 16 remains adhered to the trapping surface 14, as... Figure 5 As shown in the far right pane. Due to the transient nature of the local pH change caused by water electrolysis, the pH may revert to its level before electrolysis regeneration. Therefore, the binding sites of the calibration receptors can be restored and can retain full functionality to bind other analyte molecules for another calibration event.

[0123] The formation of gases (H2, O2, or Cl2, etc.) may not preclude calibrating sensor devices with sufficient accuracy and reliability. Gases (especially H2) can be absorbed in aqueous solutions. Alternatively, gases (especially H2) may form "nanobubbles," which do not affect calibration or only minimally affect it. The absorbed bubbles or nanobubbles may be too small to interfere with the microfluidic flow within the calibration unit.

[0124] Furthermore, a delay can be used between regeneration and subsequent calibration to allow any small amount of gas to dissolve before calibration. Alternatively or additionally, the electrolytic gas can be released through an exhaust port and / or through channels or orifices in the calibration unit. In a non-limiting example, such gas can be released from the calibration unit through the orifices of a hydrophobic mesh. Once the gas escapes from the capture surface 14, any interference with the calibration of the sensor device by such gas can be avoided.

[0125] Figure 6 An example of the fork-guided electrical region 22 is shown. Figure 6 A plan view of the capture surface 14 is shown; calibration receiver 16 ( Figure 3(Not shown) is oriented normal to the capture surface 14. When the power supply 26 provides a DC voltage to the conductive region 22, one corresponding conductive region 22 becomes an anode 28 and the other corresponding conductive region 22 becomes a cathode 30.

[0126] Figure 7 A forked guide electric field 22 is shown according to another example. In this case, multiple interlocking portions are provided on the capture surface 14. Figure 6 and Figure 7 The comb-shaped interdigitated electrodes 28 and 30 shown can help in relatively large (e.g., a few cm) applications. 2 A voltage is provided over an area (on the order of magnitude of) and can also be provided locally on surface 14, wherein local pH changes caused by water electrolysis drive the regeneration of the capture surface 14 by disrupting the binding kinetics of the receptor-analyte complex.

[0127] A similar effect can be achieved by using conductive regions 22, for example, arranged as multiple concentric ring-shaped portions.

[0128] In the first example of the regeneration component described above, regeneration is achieved by electrolyzing water molecules into H+. + and OH - This is achieved by changing the pH and releasing calibration molecules from the calibration receptor.

[0129] A second example of a regeneration assembly is based on the understanding that a potential is generated in response to fluid flow through the calibration unit. Activation of the regenerable trapping surface of the calibration unit is accomplished using an internal process after a constraint generated by the “incubation time” is met (i.e., when the condition regarding Equation 1 is satisfied). In this example, a hydrotriboelectric potential or electrochemical potential is generated by a transient or pulsating sweat flow (moving ions) through the microfluidic system, which can be used to trigger the release of calibration molecules. In other words, the generation of a hydrotriboelectric potential or electrochemical potential is proposed as a passive trigger for the release of calibration molecules. The term “passive” in this context means that the calibration unit does not actively apply a voltage or actively change the pH to regenerate the trapping surface. Instead, the hydrotriboelectric potential or electrochemical potential is generated by a transient or pulsating sweat flow (moving ions) through the microfluidic system.

[0130] For this purpose, the regeneration assembly may include: a flow channel arranged such that fluid flows through it; and a sensing electrode (or array) arranged circumferentially around the periphery of the flow channel. The sensing electrode (or array) can generate a triboelectric potential due to the mobile ions in the fluid flowing through the flow channel. The triboelectric potential generated by the sensing electrode can correspond to the rate of the mobile ions in the fluid flowing through the flow channel, more specifically to the velocity and concentration (i.e., flow rate and concentration rate) of the mobile ions in the fluid flowing through the flow channel. Ions moving through the flow channel can interact with the sensing electrode to induce a triboelectric potential (voltage), which can be directly used as a current for regenerating the captured surface. Alternatively or additionally, the calibration unit may include: a flow channel arranged such that fluid flows through it; and one or more ion-selective electrodes arranged inside the flow channel. The ion-selective electrodes can generate an electrochemical potential due to the mobile ions in the fluid flowing through the flow channel. The electrochemical potential generated by the ion-selective electrodes can correspond to the rate or concentration of (specific) mobile ions in the fluid flowing through the flow channel. Ions moving through the flow channel can interact with an ion-selective electrode to induce an electrochemical potential (voltage), which can be directly used as a current for regenerating the capture surface.

[0131] By using electrodes in the calibration unit, once new fluid is generated, a liquid triboelectric potential or electrochemical potential (transient signal) is generated through the (initial) transient or pulsating fluid flow / pressure wave (moving ions) of the microfluidic system. The generated signal is collected by sensing electrodes placed circumferentially around the flow channels of the microfluidic system or by internal ion-selective electrodes, and can be used to passively trigger the release of calibration molecules.

[0132] Figure 8 A schematic diagram of electrodes and a flow channel according to a second example of a regeneration assembly is shown. The regeneration assembly 20b includes a flow channel 34 and an electrode arrangement 36, which includes electrodes, either inductive electrodes circumferentially arranged outside the channel 34 or ion-selective electrodes inside the channel 34. A fluid from the skin (e.g., sweat excreted by the skin, interstitial fluid extracted from the skin) flows into the flow channel 34. The fluid can be considered as mobile ions in water, and these ions interact with the electrode arrangement to generate a potential. The fluid may include, for example, sodium ions (Na+). + OH- ions - Chloride ions Cl - and / or hydrogen ions H + .

[0133] Figure 9A cross-section of an exemplary sensing electrode is shown. Electrode arrangement 36 includes a first sensing electrode 36a and a second sensing electrode 36b, wherein a fluid channel 34 is provided in cooperation with the sensing electrodes. The first sensing electrode 36a and the second sensing electrode 36b may be formed of copper. Figure 8 The diagram shows a cross-section of the fluid channel 34, which can be formed of silicone, PTFE, etc. A fluid (e.g., sweat) comprising mobile ions can be supplied across the first sensing electrode 36a and the second sensing electrode 36b. Therefore, a triboelectric potential is generated by the mobile ions. The "wake-up" signal will suggest that the signal first reach the "processor" that processes the signal so that regeneration can be performed using a different power source.

[0134] Alternatively, a hydrodynamic triboelectric potential or electrochemical potential can be used as a wake-up signal to trigger the activation of the regeneration component. For example, the wake-up signal can be provided to the power supply controlling the regeneration component (e.g., Figure 4 The power supply 26) is controlled by a controller to activate the controller and wake up the regenerative components. In a wake-up system with triboelectric charge-sensing electrodes, the voltage difference between the electrode pairs is measured by an amplifier with a very large input impedance (e.g., 200 TΩ). Because triboelectric signals typically have a high optimal output impedance, they need to be matched and converted into a suitable wake-up current using power conversion electronics. This signal is typically an alternating current (AC) signal and may need to be rectified before being used by the woken electronic equipment.

[0135] A significant advantage associated with the second example is that it is not necessary to provide energy to the capture surface of the calibration unit to regenerate the capture surface.

[0136] A third example of a regeneration component is based on the understanding that the initial pH of the droplets excreted on the skin surface (such as sweat, sebum, and interstitial fluid) is around 2, which is acidic enough to support the release of calibrating molecules. Subsequently, as the flow rate increases, the pH gradually rises until it reaches a near-neutral pH (i.e., pH ~ 7).

[0137] For example, in the case of sweat samples, Figure 10The sweating rate and pH value during a 60-minute effort at a self-selected pace are shown (Coyle et al., Proceedings of the 3d International ICST Conference on Pervasive Computing Technologies for Healthcare, pp. 4–9, ICST, 2009). This occurs due to the inverse relationship between the ion reabsorption flux along the sweat ducts and the sweating rate (Sonner et al., Biomicrofluidics 9, 031301, 2015). Therefore, it is important to emphasize here that only the first portion (e.g., sweat droplets) of fluid droplets (one or more) appearing on the skin surface from active sweat glands has a pH value of 2, and only this first portion is used to release calibrating molecules. If we assume that the first portion of sweat is in hemispherical droplets... Sweat appears on the skin surface in the form of droplets with a radius of 30-50 micrometers. The average sweat rate is 0.2 nanoliters / minute / gland, and during sweating, the rate is 1.2 nanoliters / minute / gland (sweat glands function by excretion, with a typical cycle of 30 seconds of sweat production followed by 150 seconds of no sweat production). There are 10 active sweat glands per square centimeter. The volume of sweat at pH 2 and the time required for droplet formation can be estimated. The sweat droplet volume V is:

[0138]

[0139] Furthermore, the time t required for droplet formation (per gland) can be represented by volume V and sweat rate Q, as shown below:

[0140]

[0141] The timing of these sweat droplets formation is reasonable and feasible in practice.

[0142] The following describes a method for delivering fluid droplets to a calibration capture surface, utilizing methods for sweat droplets, by means of electromechanical (e.g., electrowetting) or chemical gradients. The first portion of the fluid droplets (e.g., sweat droplets) appearing on the skin surface releases calibration molecules to form a calibration liquid.

[0143] Figure 11An exemplary regeneration assembly 20c according to a third example is schematically depicted in cross-sectional view. This exemplary regeneration assembly is essentially a fluid collection assembly for providing a fluid sample to a calibration unit and sensor device. The fluid collection assembly is specifically configured for droplet discretization (e.g., sweat droplet discretization) and thus allows a first portion of sweat (i.e., one or more droplets) present on the skin to be delivered to the calibration unit. This first portion has a pH of 2, thus being acidic enough to support the release of calibration molecules. Therefore, when calibration is required, the fluid collection assembly is used to collect the first portion of sweat droplets excreted on the skin surface, which supports the release of calibration molecules to form a calibration fluid.

[0144] The regeneration component 20c includes a chamber 38 having an inlet 40. The inlet 40 receives fluid, such as sweat, from the skin 42. Figure 11 As shown, the inlet 40 can be located near the surface of the surface layer 42. Although in Figure 11 A single chamber 38 is depicted, but this is not intended to be limiting; in other examples, the regeneration assembly 42 may include multiple chambers 38.

[0145] To facilitate understanding of the apparatus and method described herein, sweat will be described below. Sweat secreted by sweat glands enters through inlet 40 and fills chamber 38. (As...) Figure 11 As shown, the regeneration assembly 20c may include a plate 44 attached to the surface of skin 42. In the example shown, the lower surface of the plate 44 is in direct contact with the surface of skin 42. In this case, the chamber 38 takes the form of an opening defined by the plate 44. The plate 44 can be formed of any suitable material (e.g., a polymer) that can be disposed on the skin. For example, the plate 44 may have at least a degree of flexibility to allow it to be conformally applied to the surface of skin 42. A more rigid plate 44 may also be considered if the inlet 40 can receive sweat from skin 42.

[0146] To collect the subject's sweat, the plate 44 can be adhered to the surface of the skin 42, for example, using a suitable biocompatible adhesive. Alternatively, the plate 44 can be held against the surface of the skin 42 by fasteners (e.g., straps) for attaching the plate 44 to the subject's body.

[0147] Preferably, the diameter of the inlet 40 for receiving sweat from the skin 42 is selected to be relatively small, for example, 200-2000 μm, 300-1200 μm, or approximately 360 μm or approximately 1130 μm. The diameter of the sweat gland outlets on the surface of the skin 42 is typically in the range of approximately 60 μm to 120 μm. A relatively small inlet 40 can help reduce the chance of two or more sweat glands excreting into the same inlet 40, which could complicate the interpretation of sensor signals. To compensate for the limited amount of sweat received in a single chamber 38, the regeneration assembly 20c may, for example, include multiple such chambers 38, such as 2 to 50 chambers 38, 10 to 40 chambers 38, or approximately 25 chambers 38.

[0148] Once chamber 38 is filled with sweat, sweat droplets 46 protrude from outlet 48 of chamber 38. Figure 11 In the example shown, outlet 48 is defined by the upper surface of plate 44, and once chamber 38 is filled with sweat, hemispherical sweat droplets 46 form on top of outlet 48.

[0149] More generally, the regeneration component 20c can be configured such that the formation rate of sweat droplets 46 is determined by the sweating rate, while the volume of sweat droplets 46 is determined by the fluid delivery component.

[0150] The corresponding areas of the inlet 40 and outlet 48 can be selected to ensure effective filling of the chamber 38 and formation of sweat droplets 46 within a certain perspiration rate range. In some examples, the inlet 40 and outlet 48 are chosen to be of fixed dimensions for this purpose. Alternatively, the regeneration component 20c can be configurable, allowing at least some dimensions and geometries associated with the formation of sweat droplets 46 to be varied.

[0151] In the preferred example ( Figure 11 (Not shown in the image), the size of chamber 38 is designed to fill with sweat within 10-15 minutes. After chamber 38 is filled, the formation of hemispherical sweat droplets 46 preferably occurs typically within 10 seconds at a relatively low sweating rate, for example, 0.2 nanoliters / minute / gland.

[0152] The diameter of the outlet 48 can be, for example, in the range of 10 μm to 100 μm, such as 15 μm to 60 μm, or approximately 33 μm, to help control the size of sweat droplets, making their volume uniform and reproducible. Because the outlet 48 has such a diameter, for example, approximately 33 μm, several sweat droplets 46 can be formed during a single sweating episode (typically lasting 30 seconds) from the sweat gland, even if the sweating rate is as low as 0.2 nanoliters / minute / gland. Therefore, sufficient sweat droplets 46 can be generated and delivered by the regeneration component 20c to the calibration unit 10 for reliable estimation of the sweating rate.

[0153] The regeneration component 20c enables the formation of relatively uniformly sized sweat droplets 46, and can also handle variable volumes of sweat droplets 46. Regarding the latter, the calibration unit to which the regeneration component 20c delivers the sweat droplets 46 can be configured to both count the sweat droplets 46 and determine the time taken for each sweat droplet 46 to pass through the calibration unit 10. This time is linearly related to the volume of the sweat droplet 46 by a priori known migration speed.

[0154] As Figure 11 The proportions of the exemplary regeneration assembly 20c shown are indicated by the dimensions of chamber 38, inlet 40, and outlet 48, which can be selected based on, for example, the perspiration rate of the object. The volume of chamber 38 can be minimized to reduce filling time. This can help ensure minimal delay between actual sweat excretion and sensing / monitoring of sweat droplets 46. For example, the volume of chamber 38 can be in the range of 0.1-100 nml, such as 0.5-50 nml, or 1-20 nml.

[0155] The volume of chamber 38 can be minimized in various ways to minimize the time required for chamber 38 to fill with sweat. Such a modification could be, for example, a modification of the plate 44 that defines chamber 38.

[0156] Figure 11 An example is shown where chamber 38 tapers gradually from inlet 40 toward outlet 48. (Illustrated) Figure 11 The length of the plate 44 shown is approximately 500 μm. The conical chamber 38 in this example has a conical geometry, i.e., a truncated cone shape, with a volume of 1 / 3πh[R]. 2 +Rr+R 2 (h = 50 μm; R = 360 μm; r = 33 μm). For a relatively low sweating rate of 0.2 nanoliters / minute / gland, the filling time of the conical chamber 38 can be approximately 10 minutes, and the formation of sweat droplets 46 can take approximately 12 seconds. In contrast, the filling time of the conical chamber 38 is approximately 10 minutes. Figure 1 The cylindrical chamber 38 shown, with the same height (50 μm) and bottom (360 μm) dimensions, may take approximately 50 minutes to form, and the hemispherical sweat droplets 46 may take more than 3 hours to form.

[0157] In this respect, it is noted that sweat glands tend to secrete during sweating, with a resting period following each sweating burst during which the glands do not secrete. During a sweating burst, the rate of sweating can be approximately six times the average rate. This is because, within a 180-second time window, there is typically a 30-second sweating burst and a typical 150-second resting period, resulting in a six-fold difference between the average sweating rate and the sweating rate during a sweating burst. In the above illustrative example with a truncated conical chamber 38, the time for the depicted sweat droplets 46 to form during sweating is approximately 12 seconds.

[0158] exist Figure 11 In the example shown, 56% of the surface area of ​​the sweat droplet 46 is in contact with the upper surface of the plate 44. The upper surface of the plate 44 may be provided with a gradient, such as a topological and / or chemical gradient, for releasing the sweat droplet 46 from the outlet 48 and transporting the sweat droplet 46 to the sensor, which will be discussed further below regarding the fluid transport assembly. At this point, it can be said that, in the case of such a topological and / or chemical gradient, the surface area of ​​the sweat droplet 46 required to contact the upper surface of the plate 44 for release from the outlet 48 can depend on the steepness of the chemical and / or topological gradient and the volume of the sweat droplet 46.

[0159] Alternatively, chamber 38 may be a cylindrical chamber (not shown) with the same height and bottom diameter.

[0160] Furthermore, the regeneration component 22c includes a fluid delivery component arranged to release sweat droplets 46 protruding from the outlet 48. Therefore, the fluid delivery component may include, for example, a structure that separates the sweat droplets 46 (e.g., hemispherical sweat droplets 46) from the outlet 48.

[0161] Due to the intermolecular attraction between water molecules in sweat, the formed sweat droplets 46 can be fixed onto most of the sweat that has already filled the cavity 38.

[0162] In practice, sweat droplets 46 do not have a single contact angle value, but rather a range from the maximum to the minimum contact angle, which are referred to as the advancing contact angle and the receding contact angle, respectively. The difference between the advancing and receding contact angles is called contact angle hysteresis.

[0163] These forces prevent sweat droplets 46 from moving from outlet 48. This force causes sweat droplets 46 to remain above the filled chamber 38. A fluid delivery assembly allows these forces to be overcome, for example, by separating the sweat droplets 46 (and delivering the sweat droplets 46 downstream toward the sensor). The fluid delivery assembly can be configured to allow sweat droplets 46 to be definitively discharged from chamber 38. In other words, the separation of sweat droplets 46 ensures a definitive definition of discrete sweat droplets 46.

[0164] The fluid delivery assembly may be provided with passive and / or active gradients for removing (i.e., releasing) sweat droplets 46. Passive gradients may include chemical and / or topological gradients. Effective gradients can be provided by applied pressure and / or by the electric field of the electrowetting device.

[0165] In some examples, the separation or release of sweat droplets 46 may occur at the moment when the sweat droplets 46 reach a certain diameter. At this diameter, the active and / or passive gradient (e.g., a gradient that may be experienced by at least a portion, preferably all, of the sweat droplets 46) may be large enough to overcome the contact angular hysteresis of the sweat droplets 46, so that the sweat droplets 46 are released from the outlet 48.

[0166] Figure 11 An example of sweat droplet 46 separation achieved through electrowetting technology is illustrated. This can be considered an example of an "active" interfacial tension method, in which a force is actively applied to overcome the contact angular hysteresis of the sweat droplet 46.

[0167] like Figure 11 As shown, the upper surface of plate 44 is provided with a series of discrete electrowetting tiles 50. For the purpose of separating and / or conveying water-containing sweat droplets from outlet 48, the electrowetting tiles 50 may include electrodes coated with a hydrophobic material (e.g., a fluoropolymer). The conveying assembly may include an electric field generator (not shown) for sequentially charging and discharging each electrowetting tile 50 in the series. Charging of the electrowetting tile 50 can cause the surface properties of the electrowetting tile 50 to change from hydrophobic to hydrophilic, thereby instantaneously overcoming the contact angular hysteresis of the sweat droplet 46. The sweat droplet 46 can then migrate onto the charged electrowetting tile 50 accordingly. Subsequent discharging of the charged electrowetting tile 50 and charging of subsequent electrowetting tiles 50 in the series can cause the sweat droplet 46 to migrate to subsequent electrowetting tiles 50, etc. This sequence can be considered an "electroplastic wave," which causes the sweat droplet 46 to move in direction 53 to the calibration unit.

[0168] exist Figure 11 In the example shown, detachment from the outlet 48 can occur when the sweat droplet 46 has grown to a sufficiently large diameter such that it at least partially overlaps with a pair of electrowetting tiles 50. In this case, once the electrowetting wave passes along the electrowetting tiles 50, the sweat droplet 46 spanning the pair of electrowetting tiles 50 will be expelled from the outlet 48 accordingly. In this example, the sweat droplets 46 may not all have a uniform size or volume because they may continue to grow to different extents during the time interval between when they reach the desired diameter and when the electrowetting wave arrives. In this respect, the size of the sweat droplet can be determined by the frequency of the electrowetting wave.

[0169] In an alternative example (not shown), the fluid delivery assembly may employ a “passive” gradient to release sweat droplets 46 from outlet 48. The term “passive” as used herein generally refers to the fluid delivery assembly not actively applying force to overcome the contact angular hysteresis of the sweat droplets 46.

[0170] For example (not shown), the upper surface of plate 44 may have a chemical and / or topological gradient that allows sweat droplets 46 to separate from outlet 48. The topological gradient may be provided by the inclined upper surface of plate 44 such that the inclined gradient across the diameter of sweat droplets 46 is large enough to overcome contact angular hysteresis when the regeneration assembly 20c is used in a oriented manner. The chemical gradient may be provided by a surface having hydrophilic and hydrophobic portions thereon, these portions being configured to provide a wettability gradient along the surface. For example, microfluidic channels functionalized with hydrophobic CH3- portions (towards skin 106) and hydrophilic OH- portions (towards the sensor) can be used to generate the chemical gradient (Morgenthaler et al., Langmuir; 2003; Vol. 19, No. 25, pp. 10459-10462).

[0171] The chemical gradient can, for example, have hydrophilic / hydrophobic regions at the molecular level, such that the wettability gradient varies substantially continuously along the surface. This chemical gradient can be provided, for example, by functionalizing the surface of the grafted polymer chains of the plate 44. Alternatively or additionally, μm-sized hydrophilic / hydrophobic regions can be provided on the surface to provide a stepped wettability gradient. Preferably, these regions are arranged to have a gradually varying distribution along the surface length in the sensor direction.

[0172] When using this passive gradient (e.g., chemical and / or topological gradient) to separate sweat droplets 46, separation may occur when the sweat droplets 46 (e.g., hemispherical sweat droplets 46) reach a certain size. Once the diameter of the sweat droplets 46 makes the gradient across the diameter large enough to overcome contact angular hysteresis, the sweat droplets 46 will detach from the outlet 48. In this sense, this gradient can cause each sweat droplet 46 to be transported to a sensor with similar size / volume to each other. After the sweat droplets 46 separate, viscous drag can also act to impede the movement of the sweat droplets 46 due to the driving force generated by the surface energy gradient.

[0173] exist Figure 11In the example shown, the fluid delivery assembly includes an additional plate 52, which is separate from and opposite the plate 44 defining the chamber 38. The additional plate 52 allows for control of the volume of the sweat droplets 46. This can be achieved, for example, by separating the additional plate 52 from the plate 44 by a defined distance 54. The size of the sweat droplets 46 can increase until it contacts the additional plate 52. In effect, when the sweat droplets 46 contact the additional plate 52, they can detach by “jumping” onto it. This can be considered another example of an interfacial tension method for separating sweat droplets 46 from the outlet 48.

[0174] In this example, calibration unit 10 may be pre-loaded with, for example, sweat droplets, such that the capture surface 14 of calibration unit 10 captures analyte molecules 18 representing a known amount of calibration molecules. A first portion of the sweat droplets appearing on the skin surface is used to release molecules to form a calibration liquid, as the pH of the first portion of the sweat droplets is around 2. The calibration liquid is then delivered to sensor device 60 for calibration.

[0175] A significant advantage associated with the third example is that it is not necessary to supply power to the capture surface of the calibration unit to regenerate the capture surface.

[0176] Figure 12 An example of a body fluid monitoring device 200 for detecting analytes in a fluid sample of a subject is schematically illustrated. In some examples, the body fluid monitoring device 200 can detect body fluids (e.g., sweat, sebum, and interstitial fluid) from a user's skin and can be associated with continuous or semi-continuous monitoring of the user, particularly with the user's fluids and / or the characteristics of those fluids. In some examples, the body fluid monitoring device 200 can detect other body fluids, such as blood, urine, and saliva. Examples of body fluid monitoring devices can include, for example, wearable devices, patches, insertable devices, and implantable devices. For example, the body fluid monitoring device 200 can be a wearable patch on the skin to measure sweat, an implantable device in interstitial fluid or blood, a toothbrush to measure saliva, a baby bottle to measure breast milk, a breast pump to measure breast milk, a toilet seat sensor to measure urine, an in vitro blood measurement device, etc.

[0177] The body fluid monitoring device 200 includes a calibration unit 10 according to any example described above.

[0178] The body fluid monitoring device 200 also includes a sensor device 60 having a capture surface 62 on which sensor molecules 64 are immobilized for detecting analytes in a fluid sample. In some examples, the sensor molecule 64 may be a receptor for binding analyte molecules. In some examples, the sensor molecule may be, for example, an enzyme to facilitate the conversion of the analyte into a product. This conversion provides a measurable signal. Figure 3An exemplary sensor device is shown. The sensor device 60 is in fluid communication with the calibration unit 10 at least during calibration events.

[0179] The body fluid monitoring device 200 also includes a fluid collection assembly 66 for supplying fluid samples to the calibration unit 10 and the sensor unit 60.

[0180] In this example, calibration unit 10 and sensor device 60 are arranged in the same delivery channel 68. Calibration molecules are bound to the capture area of ​​calibration unit 10. The bound calibration molecules do not interfere with the detection of sensor device 60 with sufficient accuracy and reliability during body fluid monitoring. The release of calibration molecules is triggered by calibration requirements. This may be due to time since the last calibration (i.e., drift) and / or abnormal measurements and / or an increase in background signal. The released calibration molecules are then delivered to sensor device 60, which measures a known volume of calibration molecules. The values ​​derived from sensor device 60 are used to calibrate sensor device 60.

[0181] In this example, because the capture surface of calibration unit 10 is in the delivery channel, just like the sensor device 60, the stability of the calibration acceptor may also be affected by contact with the biological fluid. However, in the case of an electrochemical sensor, the degree of degradation differs between the enzyme on the sensor device and the antibody on the calibration unit. The antibody has thus been shown to be more stable. Therefore, the ability to capture calibration molecules to provide a constant amount of calibration molecules throughout the entire lifetime of the wearable / patch is provided. Furthermore, any fouling mechanisms will be offset by the same elution process used in the regeneration process. This ensures a stable quantity of calibration molecules captured and released by the capture surface.

[0182] Figure 13 Another example of a body fluid monitoring device 200 is illustrated schematically.

[0183] In this example, the body fluid monitoring device 200 includes two delivery channels 68a and 68b. A calibration unit 10 is disposed within delivery channel 68b, while a sensor device is disposed within delivery channel 68b. A valve device 70 is configured to control the fluid flow between the two delivery channels.

[0184] This example is designed for extended time, which benefits from reducing the residence time of the capture zone of calibration unit 10 in the biological fluid. Specifically, calibration unit 10 is loaded only when valve device 70 is configured to allow fluid delivery to delivery channel 68b. After sufficient loading time, the capture surface of calibration unit 10 is dried using a capillary pump and evaporator device 72, making the calibration molecules bound to the capture surface of calibration unit 10 less prone to degradation. When calibration is required, valve device and regeneration assembly are configured to release calibration molecules and deliver them to sensor device 60.

[0185] All definitions used in this document should be understood as being above dictionary definitions, definitions in referenced literature, and / or the general meaning of the defined terms.

[0186] Unless otherwise expressly stated, the words “a” and “an” as used in this specification and claims shall be understood to mean “at least one”.

[0187] The phrase “and / or” as used in this specification and claims should be understood to mean “any one or two” of the elements so combined, that is, elements that exist together in some cases and separately in others. Multiple elements listed with “and / or” should be interpreted in the same way, that is, “one or more” of the elements so combined. In addition to the elements specifically identified by the “and / or” clause, other elements may optionally be present, whether related to or unrelated to those specifically identified.

[0188] The word “or” as used herein in the specification and claims should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” should be interpreted as inclusive, that is, including at least one, but also including multiple elements or more than one element in a list of elements, as well as (optionally) additional unlisted items. In general, the term “or” as used herein should only be interpreted as indicating an exclusive choice (i.e., “one or the other, but not both”) before exclusive terms such as “any one” or “one of them”.

[0189] The phrase "at least one" as used herein in the specification and claims, referring to a list of one or more elements, shall be understood to mean at least one element selected from any one or more elements in the list of elements, but not necessarily including at least one element from every element specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition also allows for optional elements other than those specifically identified in the list of elements referred to by the phrase "at least one," whether related to or unrelated to those specifically identified elements.

[0190] In the claims and the description above, all transitional phrases (such as “comprising,” “including,” “having,” “containing,” etc.) should be understood as open-ended (i.e., meaning including but not limited to).

[0191] In another exemplary embodiment of the present invention, a computer program or computer program unit is provided, characterized in that it is adapted to run method steps of a method according to an embodiment of the foregoing embodiments on a suitable system.

[0192] Therefore, a computer program unit can be stored in a computer unit, and this computer program unit can also be part of an embodiment of the present invention. The computing unit can be adapted to perform or cause the execution of steps of the above-described method. Furthermore, the computing unit can be adapted to operate components of the above-described apparatus. The computing unit is capable of automatically operating and / or executing user commands. The computer program can be loaded into the working memory of a data processor. Therefore, a data processor can be equipped to execute the method of the present invention.

[0193] This exemplary embodiment of the invention covers both computer programs that use the invention from the outset and computer programs that use the invention by means of updating existing programs.

[0194] Additionally, the computer program unit may be able to provide all the necessary steps to complete the process of an exemplary embodiment of the method as described above.

[0195] According to another exemplary embodiment of the present invention, a computer-readable medium, such as a CD-ROM, is provided, wherein the computer-readable medium has computer program units stored on the computer-readable medium, the computer program units being described in the preceding sections.

[0196] Computer programs can be stored and / or distributed on suitable media, such as optical storage media or solid-state media supplied together with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0197] However, computer programs can also exist on networks (such as the World Wide Web) and can be downloaded from such networks to the working memory of a data processor. According to another exemplary embodiment of the invention, a medium is provided for making computer program units available for download, said computer program units being arranged to perform a method according to one of the foregoing embodiments of the invention.

[0198] While several embodiments of the invention have been described and illustrated herein, those skilled in the art will readily conceive of various other units and / or structures for performing functions and / or achieving results and / or one or more of the advantages described herein. Each such variation and / or modification is considered to be within the scope of the embodiments of the invention described herein. More generally, those skilled in the art will readily understand that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on one or more specific applications using the teachings of this invention. Those skilled in the art will recognize or be able to determine many equivalents of the specific embodiments of the invention described herein using experimental means not exceeding those of conventional methods. Therefore, it should be understood that the foregoing embodiments are presented by way of example only, and that embodiments of the invention may be practiced in ways different from those specifically described and claimed within the scope of the claims and their equivalents. The embodiments of the invention disclosed herein relate to each individual feature, system, article, material, kit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials, kits, and / or methods can be included within the scope of the invention disclosed herein if such features, systems, articles, materials, kits, and / or methods do not contradict each other.

Claims

1. A calibration unit (10) suitable for calibrating a sensor device (60), said sensor device being adapted to detect analyte molecules (18) in a fluid sample of an object, said calibration unit comprising: A calibration matrix (12) having a trapping surface (14) on which a calibration acceptor (16) adapted to reversibly bind a known amount of the analyte molecule (18) in a fluid sample of the object is immobilized, wherein the bound analyte molecule represents a calibration molecule that can be used to calibrate the sensor device; and Regeneration components (20, 20a, 20b, 20c) are configured to regenerate the capture surface by releasing the calibration molecules from the capture surface (14) into an aqueous solution to form a calibration fluid for calibrating the sensor device.

2. The calibration unit according to claim 1, in, The aqueous solution is a fluid sample of the object.

3. The calibration unit according to claim 1 or 2, in, The regeneration component is configured to apply a potential to the capture surface to release the calibration molecule from the capture surface.

4. The calibration unit according to claim 1 or 2, in, The regeneration assembly includes an electrolysis assembly (20c) configured to electrolyze the aqueous solution.

5. The calibration unit according to claim 4, in, The electrolysis assembly includes: At least three spatially separated conductive regions (22) on the capture surface; and The power supply, which is configured to implement: A first configuration, in which a first pair of conductive regions separated by at least three spaces supplies a voltage sufficient to electrolyze the aqueous solution received on the capture surface; and In a second configuration, a second pair of conductive regions spanning the at least three spatially separated conductive regions provides a voltage sufficient to electrolyze the aqueous solution received on the capture surface, the second pair of combinations being different from the first pair of combinations.

6. The calibration unit according to any one of claims 1, 2, and 5, further comprising: Component (20b), which includes: Flow channel (34), which is arranged to allow the aqueous solution to flow through the flow channel; and Electrode arrangement (36) includes at least one of a sensing electrode and an ion-selective electrode; The sensing electrode is arranged circumferentially around the periphery of the flow channel and configured to generate a triboelectric potential in response to moving ions in the aqueous solution flowing through the flow channel; and The ion-selective electrode is disposed inside the flow channel and configured to generate an electrochemical potential in response to moving ions in the aqueous solution flowing through the flow channel.

7. The calibration unit according to claim 6, in, The component is: (i) a regeneration component configured to apply at least one of the triboelectric potential and the electrochemical potential to the trapping surface to release the calibration molecule from the trapping surface; or (ii) a triggering component configured to trigger activation of the regeneration component when at least one of the generated triboelectric potential and the generated electrochemical potential exceeds a predetermined threshold corresponding to a given ion migration rate.

8. The calibration unit according to claim 1 or 2, in, The regeneration assembly includes a fluid collection assembly (20c), which includes: A chamber (38) having an inlet (40) and an outlet (48), the inlet being for receiving droplets (46) of a fluid sample excreted onto the skin surface, and the outlet being arranged such that, after the chamber is filled with the fluid sample, droplets of the fluid sample form and protrude from the outlet. A fluid delivery assembly (50) is configured to release the droplet protruding from the outlet and deliver the released droplet to the calibration matrix, thereby enabling the outlet to be used for the formation of subsequent droplets and to protrude from the outlet during further filling of the chamber; The fluid delivery assembly is arranged to deliver the released droplets at least as fast as the subsequent droplets emerge from the outlet, such that the droplets do not contact each other; and The fluid delivery assembly is configured to deliver one or more droplets initially excreted on the skin surface to the calibration matrix to release the calibration molecules from the capture surface, thereby forming the calibration fluid.

9. The calibration unit according to any one of claims 1, 2, 5, and 7, in, The calibration matrix is ​​configured to release different amounts of calibration molecules into the aqueous solution to form calibration fluids with different concentrations, thereby constructing calibration curves to calibrate the sensor device.

10. The calibration unit according to claim 9, in, Calibration fluids with different concentrations are formed by at least one of the following: The regeneration component is activated at different time intervals to release the calibration molecules from the capture surface, thereby producing different concentrations; Multiple capture regions are provided, each of which has a different amount of calibration receptor, such that each capture region releases a different amount of calibration molecule; as well as The calibration receptors have different types, each of which is configured to release the calibration molecule with different amounts of hydrogen ions.

11. The calibration unit according to claim 10, further comprising: A capillary pump configured to remove fluid from the plurality of capture zones; as well as An evaporator, which is configured to evaporate the fluid removed.

12. A body fluid monitoring device for detecting analytes in a fluid sample of an object, the body fluid monitoring device comprising: The calibration unit (10) according to any one of the preceding claims; A sensor device (60) having a capture surface (62) on which sensor molecules (64) are immobilized for detecting the analyte in the fluid sample, wherein the sensor device is in fluid communication with the calibration unit at least during a calibration event; and A fluid collection assembly (66) is used to supply the fluid sample to the calibration unit (10) and the sensor device (60).

13. The body fluid monitoring device according to claim 12, comprising: (i) A delivery channel (68) arranged to accommodate both the calibration unit and the sensor device; or (ii) Two delivery channels (68a, 68b) and a valve arrangement, the two delivery channels being arranged to respectively accommodate the calibration unit and the sensor device, and the valve arrangement being configured to control the flow of fluid between the two delivery channels.

14. A method (300) for calibrating a sensor device (60) for detecting an analyte in a fluid sample of an object, the method comprising: a) Receive a fluid sample of the object (310) using the calibration unit (10); The calibration unit (10) includes a calibration matrix (12) having a capture surface (14) on which a calibration acceptor (16) is fixed. b) Using the calibration receptor (16), reversibly binds (320) a known amount of analyte molecules (18) in the fluid sample of the object, wherein the bound analyte molecules represent calibration molecules that can be used to calibrate the sensor device (60); and c) The capture surface (330) is regenerated using a regeneration component by releasing the calibration molecules from the capture surface (14) into an aqueous solution to form a calibration liquid; and d) The released calibration molecules are delivered (340) to the sensor device (60) for calibration of the sensor device.

15. A computer program product for calibrating a sensor device (60) for detecting analytes in a fluid sample of an object, the computer program product being adapted, when run by a processor, to perform the method according to claim 14.

Images