Device for quantitatively measuring cationic electrolyte concentration and creatinine concentration and their ratio

Abstract

The present invention relates to a disposable test strip for quantitatively determining the concentration of non-sodium cationic electrolytes and the concentration of creatinine and for subsequent determination of their ratio, and to a non-invasive point-of-care (POC) device for detecting electrolyte imbalance in a patient. In addition, the present invention relates to a method for simultaneously quantitatively determining the concentration of cationic electrolytes and the concentration of creatinine in a urine sample of a patient, and to a method for detecting electrolyte imbalance in a patient.

Description

Technical Field

[0001] The present invention relates to a disposable test strip for quantitatively determining the concentration of non-sodium cationic electrolytes and the concentration of creatinine and for subsequent determination of their ratio, and to a non-invasive point-of-care (POC) device for detecting electrolyte imbalance in a patient. In addition, the present invention relates to a method for simultaneously quantitatively determining the concentration of cationic electrolytes and the concentration of creatinine in a urine sample of a patient, and to a method for detecting electrolyte imbalance in a patient. Background Art

[0002] The body contains a wide variety of electrolytes that are essential for human and animal health. Each electrolyte plays a specific role in the body, and their good balance is essential for many physiological functions, such as hydration, extracellular and intracellular pH, metabolism, nerve impulses, bone density, and muscle contraction / relaxation. Among the important electrolytes are cationic electrolytes, especially the positively charged potassium ion (K + ), calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), copper ions (Cu 2 + )) and zinc ions (Zn 2+ ).

[0003] Electrolyte imbalance, including deficiency and / or overload of such electrolytes in the patient's body, may occur due to inadequate intake and / or disturbed excretion of these electrolytes, which may occur in a variety of acute and chronic disease states (e.g., renal dysfunction, gastrointestinal disease, during infections causing severe and persistent diarrhea or vomiting, and due to drugs that cause electrolyte losses in the urine (diuretics)) ([1]).

[0004] Potassium (K) is the most important intracellular cation. K is involved in a large number of vital processes in every cell, and K imbalance can lead to severe cellular unresponsiveness and dangerous arrhythmias ([2]). Potassium deficiency can be caused by reduced K uptake associated with dietary disturbances, as well as by increased K transfer to cells due to, for example, insulin administration, sympathetic nervous system stimulation, thyreotoxicosis, and familial periodic paralysis. However, the most important mechanism leading to potassium deficiency remains increased K loss, primarily through the kidneys and / or the gastrointestinal tract ([3]). Renal potassium loss can be the result of acquired or inherited kidney diseases (e.g., Bartter syndrome) and endocrine disorders including Cushing syndrome, or by drugs (e.g., thiazides and osmotic diuretics, amphotericin B, penicillins, and theophillin). Gastrointestinal causes occur during prolonged vomiting and / or diarrhea during infections, inflammatory, malignant, and hereditary enteropathy, but also as a result of laxative abuse. Less common cases of K deficiency may present with milder symptoms, such as muscle weakness and cramps, but severe cases can be fatal and must be treated immediately. Usually, oral potassium supplementation is recommended for treatment; however, careful control during treatment is necessary because potassium supplementation is also a common cause of K overload, such as in hospitalized patients.

[0005] On the other hand, potassium overload is a common clinical abnormality in chronic kidney disease, but is also often the result of high dietary potassium intake and medications known to increase potassium levels. Further risk factors for overload are acute kidney injury, cardiovascular disease, and diabetes ([4]). K overload can be asymptomatic, meaning that it causes only vague symptoms, including nausea, fatigue, muscle weakness, or tingling. However, if not diagnosed and treated, the condition can be fatal, leading to cardiac arrest and death. Patients with chronic KO are advised to reduce dietary potassium, and close monitoring is essential.

[0006] Calcium (Ca) is required for muscle contraction, enzyme activity, and blood coagulation. Ca helps stabilize cell membranes and is essential for the release of neurotransmitters from neurons and hormones from endocrine glands. Adequate bioavailable Ca is essential for bone health. Calcium deficiency can result from vitamin D deficiency due to inadequate intake or poor assimilation as a result of many gastrointestinal diseases. In addition, a variety of metabolic disorders, including diabetes, may be associated with enhanced renal Ca losses ([5]).

[0007] Osteoporosis is a common bone disorder that may affect women and men of any age. In particular, more than 30% of all postmenopausal women suffer from clinically relevant osteoporosis with an increased risk of fractures ([6]). Currently, the most widely accepted method for diagnosing osteoporosis is the determination of bone mineral density (BMD). However, BMD measurements are technically and logistically demanding, time-consuming and expensive. Other markers of osteoporosis, such as β-crosslap and Ca excretion in a 24-hour urine collection, are used clinically to assess response to treatment, but these investigations are cumbersome and prone to error. Therefore, these methods are neither well suited for general population screening for increased Ca loss nor for monitoring Ca status during osteoporosis treatment.

[0008] On the other hand, decreased Ca excretion has been reported as a mechanism of pre-eclampsia, which affects up to 8% of pregnancies worldwide and is one of the leading causes of maternal mortality ([7]), thus requiring simpler methods for monitoring Ca status.

[0009] Magnesium (Mg) is an essential mineral that participates in more than 300 enzyme reactions and also plays an important role as a second messenger. It stabilizes the resting membrane potential of muscle and nerve cells and therefore plays a key role in neuromuscular transmission, cardiac excitability and vasomotor tone ([8]).

[0010] Consistent with these behaviors, magnesium deficiency has been reported to be associated with an increased incidence of migraines, Alzheimer's disease, coronary heart disease, hypertension, and type 2 diabetes. Hypomagnesiuria has also been described in up to 60% of patients with urolithiasis ([9]). The important role of magnesium in pre-eclampsia and eclampsia affecting pregnant women has been well established. However, although oral magnesium sulfate administration is now an accepted treatment measure in these patient groups, concerns remain regarding toxicity, which may cause diarrhea, vomiting, nausea, and severe irregular heartbeats leading to cardiac arrest (

[10] ). Therefore, simple methods for controlled supplementation and monitoring of body Mg status are extremely important for all affected patients.

[0011] Zinc (Zn) is an essential element in the body, as it is a structural component of proteins and is involved as a cofactor in a variety of enzymatic processes. Effects of zinc deficiency may include diminished immune responses, reduced healing and neurological disturbances, and reduced fetal development. Zinc deficiency may be caused by dietary factors, but it may also be caused by genetic defects that occur in patients with gastrointestinal diseases such as celiac disease or Crohn's disease, Wilson's disease, diabetes, and chronic liver and kidney disease (

[11] ). Assessment of the body's zinc status is essential, particularly for monitoring treatments such as oral zinc therapy in Wilson's disease, and for evaluating suspected nutritional deficiencies, cases of diabetes, slowed wound healing, or growth retardation.

[0012] Another electrolyte that is essential for many biological processes in the body is copper (Cu), which is part of several proteins. Copper deficiency can be the result of malnutrition and malabsorption, as well as due to hypoproteinemias, nephrotic syndrome, and Menkes disease. On the other hand, copper can be toxic when present in excess, often leading to severe liver damage (

[12] ). Copper overload occurs primarily in people with Wilson's disease. The main sources of copper for humans and animals are food, drinking water, and copper-containing supplements. In general, the copper content of the diet varies greatly because foods vary greatly in their natural copper content. Factors such as season, soil quality, geography, water sources, and fertilizer use affect the final copper content in food. Assessment of the body's copper status is necessary for monitoring therapy for Wilson's disease and for detecting obstructive liver disease.

[0013] Currently, assessment of the body's electrolyte status requires laboratory analysis, which is logistically cumbersome and prolongs the time to obtain results. It requires medical and laboratory personnel and is not suitable for monitoring and population screening, nor for self-testing (e.g., requiring venipuncture for blood testing, 24-hour urine collection). These methods do not meet the testing requirements for point-of-care (POC) diagnostics (

[13] ,

[14] ).

[0014] Electrolyte imbalances can be detrimental to a patient's health and, if left untreated, can lead to serious life-threatening problems such as kidney, respiratory or circulatory failure, or even death. Therefore, timely identification of electrolyte imbalances and simpler methods for monitoring electrolyte status are urgently needed.

[0015] Recently, the calculated concentration of electrolytes (El) to creatinine (Crea) (uEl / uCrea) in spot urine samples has become a potentially promising tool for identifying and monitoring patients at risk for electrolyte imbalance (

[15] ,

[16] ). Creatinine is a waste product of muscle metabolism and is excreted into the urine at a relatively constant rate via glomerular filtration. Within an individual, creatinine excretion concentrations are relatively stable (

[17] ). Therefore, urinary creatinine (uCrea) can be used as a normalizer for electrolyte concentrations in order to adjust for changes in the amount and rate of urine production.

[0016] However, the determination of uE1 / uCrea, as currently performed, is limited by the need to send urine samples to a laboratory where the analyte concentration is measured by one of the established laboratory methods. Therefore, this method still requires skilled personnel, considerable organizational effort, and extended time to obtain results, and is not suitable for point-of-care (POC) diagnostics.

[0017] With the advent of advanced technologies (e.g., screen printing or inkjet printing) enabling the miniaturization of electrochemical devices and the maturity of mobile technology, a new era of POC testing has emerged (

[13] ,

[14] ), potentially allowing the quantitative determination of diverse analytes such as has been demonstrated for glucose in patients with diabetes (

[18] ).

[0018] WO96 / 04554A1 describes a test strip for determining calcium loss by measuring the concentration of calcium and creatinine in urine. The method relies on two pads attached to the test strip containing dry chemical reagents, one sensitive to calcium and one sensitive to creatinine. The dry chemical reagents fixed on the pads react chemically with the analyte (if present in the urine) to produce a color change proportional to the concentration of the corresponding analyte. The readout can be made visually by a colorimetric table (preferably a colorimetric table for semi-quantitative determinations) or by a reflectometer which is not suitable for point-of-care testing settings.

[0019] To date, the main analytical methods currently used for the determination of electrolyte concentrations in biological samples are flame photometry, conventional ion-selective potentiometry, or colorimetry based on upstream chemical reactions (

[19] ). These methods require specific instrumentation and pre-analytical sample preparation; therefore, they can only be performed by trained personnel. The time required to obtain results can take hours or even days, hampering timely treatment decisions.

[0020] Now, near-care diagnostic devices that can reduce the time to obtain results are sometimes available in hospital emergency rooms or clinical laboratories. Examples of such devices are the Radiometer ABL 800 (Radiometer, Denmark) or the Cobas 6000 (Roche, Switzerland). The system is a blood gas analyzer with a disposable composite box (cartridge) containing sensors, solutions, waste bags and even samplers. However, the analysis requires an invasive step (venipuncture), and due to its complexity, the instrument is quite expensive and can only be operated by trained personnel.

[0021] The routine determination of creatinine in clinical laboratories is based on the Jaffe reaction or on the use of creatinine amide hydrolase to produce a colored compound. It is well known that these colorimetric methods are not free of interferences and analytical problems (

[20] ). Highly accurate results for creatinine are provided by isotope dilution gas chromatography-mass spectrometry. However, this method requires expensive and complex instrumentation and trained personnel, and therefore cannot be considered a feasible routine method. Recently, in order to develop a feasible routine method for the determination of creatinine, some amperometric biosensors have been reported, which mainly rely on a composite combination of three enzymes (

[21] ). Currently available on the market are (Nova Biomedical, USA), a portable clinical analyzer using this three-enzyme system fixed on a disposable pocket-sized cartridge. However, the analysis is performed with a blood sample and the test should be performed by medical personnel.

[0022] Biomedical Stat Profile Critical Care Xpress (CCX) (

[23] ) is a desktop point-of-care testing device that can detect creatinine with an error of approximately 11.4%, and can also detect other analytes including K, Ca or Mg. However, this device, like all other devices, requires blood for analysis and is therefore invasive. In addition, it is not a portable device and is quite expensive because it is an all-in-one system.

[0023] Considering the above information, it is clear that a less invasive and less expensive device is highly desirable to identify and monitor the state disturbances of essential electrolytes such as K, Ca, Mg, Zn, and Cu.

[0024] There is a great need for a less invasive, relatively inexpensive, and easy-to-use device to identify and monitor electrolyte disturbances in the body. Summary of the invention

[0025] Therefore, the object of the present invention is to provide a device for simultaneously determining the electrolyte concentration and creatinine concentration of interest in a patient's urine sample in a simple manner, and to provide such a device that can be easily operated. Another object of the present invention is to provide a method for determining the electrolyte concentration and creatinine concentration in a patient's urine sample to subsequently determine their ratio and for detecting electrolyte deficiency and / or electrolyte overload, which method is time-saving and can be implemented at point-of-care (POC). Another object of the present invention is to provide a method for detecting electrolyte deficiency and / or electrolyte overload in a patient, which method can even be implemented by untrained personnel (e.g., the patient himself). Another object of the present invention is to provide a device and method for quantitatively determining the electrolyte concentration and creatinine concentration in a patient's urine sample and for determining their ratio and / or detecting electrolyte deficiency and / or electrolyte overload in a patient, which method is not time-consuming and can be performed as a routine operation.

[0026] In a first aspect, the present invention relates to a disposable test strip for quantitatively determining the concentration of non-sodium cationic electrolytes and creatinine in a patient's urine sample.

[0027] The test strip comprises:

[0028] a substrate which is electrically insulating or has an electrically insulating layer applied thereto,

[0029] - an electrode assembly applied to said substrate or to said electrically insulating layer, if present,

[0030] The electrode assembly at least includes

[0031] - a working electrode selective for said cationic electrolyte;

[0032] - a creatinine selective working electrode;

[0033] - a joint reference electrode for both the cation electrolyte selective working electrode and the creatinine selective working electrode, or a reference electrode for the cation electrolyte selective working electrode and a separate reference electrode for the creatinine selective working electrode;

[0034] - Optionally; one or two neutral electrodes for measuring and eliminating interference;

[0035] - an interface for electrically connecting the electrode assembly to a readout instrument.

[0036] It should be noted that according to an embodiment of the present invention, the electrode assembly does not include any other working electrodes besides one working electrode selective for a cationic electrolyte and one working electrode selective for creatinine.

[0037] In one embodiment, such determination is performed by one or more potentiometric measurements.

[0038] In a preferred embodiment, the electrode assembly comprises, as reference electrode, a joint reference electrode for both the cation electrolyte selective working electrode and the creatinine selective working electrode. The advantages of a joint reference electrode are a very simple geometry and a significant reduction in material costs. With a single joint reference electrode, it is possible to design a very simple geometry for the electrode assembly, without having to take into account different positions of different (i.e. separate) reference electrodes for each working electrode. This, in turn, will reduce material costs and manufacturing costs.

[0039] In one embodiment, the working electrode, the one or more reference electrodes and the one or more neutral electrodes, if present, have been applied to the substrate or to the electrically insulating layer, if present, by a suitable deposition technique (e.g. printing, sputtering, evaporation, electroless plating, attachment, gluing or lithography, preferably screen printing or inkjet printing), thereby forming an electrode assembly on the substrate or on the electrically insulating layer, and wherein the cation electrolyte selective working electrode comprises a cation electrolyte selective membrane, and the creatinine selective working electrode comprises a creatinine selective membrane, and wherein the one or more neutral electrodes comprise a membrane that is not selective for the cationic electrolyte and is not creatinine selective.

[0040] In one embodiment, the electrode assembly is composed of

[0041] - a working electrode selective for said cationic electrolyte;

[0042] - a creatinine selective working electrode;

[0043] - a joint reference electrode for both the cation electrolyte selective working electrode and the creatinine selective working electrode, or a reference electrode for the cation electrolyte selective working electrode and a separate reference electrode for the creatinine selective working electrode;

[0044] - Optionally; one or two neutral electrodes for measuring and eliminating interference;

[0045] - An interface component for electrically connecting the electrode assembly to a readout instrument device.

[0046] In one embodiment, the non-sodium cationic electrolyte is selected from the group consisting of potassium, calcium, magnesium, zinc and copper, preferably selected from the group consisting of potassium, calcium, magnesium, zinc and copper.

[0047] In one embodiment, the substrate is made of a material selected from plastic, ceramic, aluminum oxide, paper, cardboard, rubber, fabric, carbon-based polymers (such as polypropylene), fluorine-containing polymers (such as Teflon), silicon-based substrates (such as glass, quartz, silicon nitride, silicon oxide), silicon-based polymers (such as polydimethoxysiloxane), semiconductor materials (such as elemental silicon), and dielectric materials; preferably made of a material selected from organic dielectric materials (such as polyimide, polycarbonate, polyvinyl chloride, polystyrene, polyethylene, polypropylene, polyester, polyethylene terephthalate, polyurethane, polyvinylidene fluoride), inorganic dielectric materials (such as silicon dioxide); and wherein the electrically insulating layer, if present, is made of a dielectric material, wherein, if the electrically insulating layer is present on the substrate, the electrode assembly is located on the electrically insulating layer.

[0048] More specifically, substrate can be optionally coated with an electrical insulating layer.This electrical insulating substrate is preferably made of dielectric material, and the dielectric material is preferably selected from organic dielectric material or inorganic dielectric material, organic dielectric material such as polyimide, polycarbonate, polyvinyl chloride, polystyrene, polyethylene, polypropylene, polyester, polyethylene terephthalate, polyurethane, polyvinylidene fluoride, and inorganic dielectric material such as silicon dioxide.In one embodiment, the electrode assembly applied on substrate or applied to the electrical insulating substrate if present is a part of the surface of substrate and / or forms a part of the surface of substrate, and is suitable for contacting with the sample (such as urine sample) of the patient.If electrical insulating layer is present on substrate, electrode assembly is preferably located at or applied to this electrical insulating layer.

[0049] In one embodiment, the cation electrolyte selective working electrode comprises a cation electrolyte selective membrane comprising a cation electrolyte selective carrier in a polymer matrix, and the creatinine selective membrane comprises a creatinine selective carrier in a polymer matrix.

[0050] In one embodiment, the electrode assembly further comprises one or two neutral electrodes for measuring and eliminating interference, wherein the one or more neutral electrodes comprise a membrane comprising a polymer matrix free of any cationic electrolyte selective carrier and free of any creatinine selective carrier.

[0051] In one embodiment, each of the electrodes in the electrode assembly has an electrical lead, wherein the electrical lead connects the electrode to the interface to electrically connect the electrode assembly to a readout meter device.

[0052] In one embodiment, the joint reference electrode has a surface larger than the surface of each of the working electrodes, or each of the individual reference electrodes has a surface larger than the surface of each of the working electrodes.

[0053] In yet another aspect, the present invention also relates to a non-invasive point-of-care (POC) device for detecting electrolyte imbalance in a patient, the POC device comprising:

[0054] - a readout meter device for quantitatively and selectively measuring the concentration of cation electrolytes and creatinine in a urine sample, and for determining the ratio of cation electrolytes to creatinine, the readout meter device comprising

[0055] - a receiving module for receiving an interface of a disposable test strip according to the present invention and for establishing electrical contact between the readout meter device and the electrode assembly of the disposable test strip, thereby allowing detection and transmission of one or more electrical signals from the disposable test strip to the readout meter device, wherein the receiving module has a plurality of electrical connectors for contacting each electrode respectively through the interface of the test strip;

[0056] - a multi-channel amplifier, preferably with a high input resistance, for amplifying one or more electrical signals transmitted from a single-use test strip according to the invention;

[0057] - a controller including an analog / digital converter and a storage memory for converting the electrical signals received from the single-use test strip according to the present invention into one or more cationic electrolyte concentration measurements and one or more creatinine concentration measurements, and for subsequently determining a ratio of the cationic electrolyte concentration to the creatinine concentration based on the cationic electrolyte concentration measurements and the creatinine concentration measurements;

[0058] - an output device for displaying the concentration measurement and / or said ratio to a user, preferably a display, and

[0059] -power supply.

[0060] In one embodiment, the output device may also display other data, such as earlier measured values, and may also have other functions, such as an alarm if a certain threshold is exceeded, etc. The output device may include a save / send function, etc.

[0061] In one embodiment, the controller for converting the electrical signal received from the disposable test strip according to the present invention into one or more cation electrolyte concentration measurements and one or more creatinine concentration measurements utilizes pre-stored calibration information stored in its storage memory. This pre-stored calibration information is about each analyte, i.e., cation electrolyte and creatinine. The controller additionally utilizes the Nernst equation to determine the concentration measurement of the corresponding analyte. For example, in one embodiment, wherein the electrode assembly includes a first working electrode (with a first electrical lead), a joint reference electrode (with a second electrical lead), a second working electrode (with a third electrical lead) and a neutral electrode (with a fourth electrical lead), the controller uses a first electrical signal received via a first electrical connector (lead) and a second electrical connector (lead), a second electrical signal received via a second electrical connector (lead) and a third electrical connector (lead), and, if a neutral electrode is also present, a third electrical signal received via a second electrical connector (lead) and a fourth electrical connector (lead) is used to determine sodium concentration and creatinine concentration respectively and subsequently calculate their ratio.

[0062] In one embodiment, the receiving module is in the form of a slot, recess or groove, or other suitable form that allows connection to be established with the interface of the test strip. In one embodiment, the receiving module can be configured as an edge-connector pair or a pin-and-socket-pair.

[0063] In one embodiment, the non-invasive point-of-care (POC) device according to the present invention further comprises

[0064] - Inserting a disposable test strip according to the invention into the receiving module of the read-out meter device by means of the interface of the disposable test strip, so that electrical contact is established between the electrode assembly of the test strip and the read-out meter device.

[0065] In one embodiment, the device further comprises

[0066] - a user interface for operating the device, and / or a memory for storing a plurality of cation electrolyte concentration measurements and creatinine concentration measurements and a determined ratio of cation electrolyte concentration to creatinine concentration, and / or a connection interface for transmitting and / or exchanging data with an external computer or an external network, preferably a USB connection interface and / or a wireless connection interface.

[0067] In yet another aspect, the present invention also relates to a method for quantitatively determining the concentration of cationic electrolytes and creatinine in a urine sample of a patient, comprising the steps of:

[0068] a) provide a urine sample from the patient,

[0069] b) contacting a disposable test strip according to the present invention with the urine sample and allowing the electrode assembly of the test strip to be wetted by and in contact with the urine sample, optionally removing the urine-wetted test strip from the urine sample,

[0070] c) connecting the test strip to a readout meter device of a point-of-care (POC) device as defined above, to assemble a point-of-care (POC) device as defined above, wherein the single-use test strip is inserted into the receiving module of the readout meter device, thereby establishing electrical contact between the electrode assembly of the test strip and the readout meter device,

[0071] wherein said connecting of said test strip to said point-of-care reading meter device in step c) occurs before or after step b),

[0072] d) measuring the cation electrolyte concentration and the creatinine concentration in the urine sample using the point-of-care (POC) device assembled in step c).

[0073] In a preferred embodiment, the quantitative determination is performed by potentiometric measurement. Such potentiometric measurement has the advantage that no current or potential needs to be applied to the electrode assembly and, instead, the determination involves the measurement of the potential difference existing between one or more working electrodes and corresponding one or more reference electrodes. It should also be noted that quantitative potentiometric determination No It involves the active application of a potential or current to an electrode assembly to induce a perturbation (in a sample being investigated), nor the subsequent detection of one or more effects of such a perturbation.

[0074] In another aspect, the present invention relates to a method for detecting electrolyte imbalance in a patient, the method comprising the following steps:

[0075] - performing the method according to the invention for quantitative determination of cationic electrolyte concentration and creatinine concentration,

[0076] - determining the ratio of the cationic electrolyte concentration to the creatinine concentration using the point-of-care (POC) device,

[0077] - An electrolyte balance disorder is detected if said ratio of cationic electrolyte concentration to creatinine concentration in said urine sample determined in the previous step is outside the range of physiologically appropriate ratio values ​​for the respective patient, i.e. is above or below the range of physiologically appropriate ratio values ​​for the respective patient.

[0078] In one embodiment, the electrolyte balance disorder is cation electrolyte deficiency or cation electrolyte overload, and is preferably selected from:

[0079] - a deficiency of potassium in the patient's plasma, for example due to increased renal and / or gastrointestinal potassium losses, such as may occur in acquired or hereditary kidney diseases, during diuretic intake or during prolonged vomiting and / or diarrhea during infectious, inflammatory, malignant and hereditary enteropathy,

[0080] - potassium overload in the patient's plasma, for example due to the intake of drugs that increase potassium levels or during acute kidney injury, cardiovascular disease and diabetes,

[0081] - patients with calcium deficiency, for example due to metabolic disorders, vitamin D deficiency or enhanced renal calcium loss, such as may occur in kidney stone disease, osteoporosis and diabetes,

[0082] - patients with calcium overload, for example due to decreased renal calcium loss, such as may occur in pre-eclampsia during pregnancy,

[0083] - Patients with magnesium deficiency or magnesium overload, such as may occur in urolithiasis, migraine, Alzheimer's disease, coronary heart disease, hypertension, type 2 diabetes, pre-eclampsia and eclampsia,

[0084] - patients with zinc deficiency, for example due to dietary inadequacy or gastrointestinal disorders, such as may occur in celiac disease or Crohn's disease, Wilson's disease, diabetes, chronic liver and kidney disease,

[0085] - Patients with copper deficiency, such as due to malabsorption and malnutrition, such as may occur during nephrotic syndrome, Menkes disease, and hypoproteinemia, and

[0086] -Patients with copper overload due to obstruction of renal excretion of copper, such as may occur in Wilson's disease.

[0087] In one embodiment, the physiologically appropriate range of ratio values ​​is or has been determined respectively by reference to healthy persons, preferably healthy persons of the same age, sex and / or weight.

[0088] The inventors of the present invention have provided a simple, sensitive, non-invasive, quantitative and low-cost portable disposable test strip for simultaneously quantitatively determining the concentration of cationic electrolytes (wherein the cationic electrolyte is not sodium) and the concentration of creatinine in a patient's urine sample, and have provided a non-invasive, quantitative, low-cost and portable point-of-care (POC) device for determining electrolyte balance disorders in a patient. The test strip and point-of-care device are capable of electrochemically measuring the urine concentration of cationic electrolytes and the urine concentration of creatinine for subsequent calculation or determination of their respective ratios (cationic electrolyte:creatinine) used as a marker for electrolyte balance disorders.

[0089] It should be noted that the simultaneous quantitative determination of cationic electrolyte concentration and creatinine concentration is carried out in an enzyme-free manner. Therefore, no enzyme is used for this determination, and no product of enzymatic reaction or other chemical reaction is measured / determined. This determination is based on preferably only based on potential measurement, that is, it involves the measurement of potential difference. It does not involve the measurement of electric current, and it does not involve the use of enzymes, dyes and / or dry chemicals to be fixed on the pad on the test strip. Therefore, one or more test strips according to an embodiment of the present invention do not include or involve the use of any enzyme or dry chemical to be fixed on the pad on the test strip and / or react with the cationic electrolyte or react with creatinine. More preferably, one or more test strips according to the present invention do not include dry chemicals for ultimately reacting with cationic electrolytes and creatinine, nor do they include pads on which dry chemicals are fixed.

[0090] The test strip according to an embodiment of the present invention is a disposable test strip, which means that after being used once for measuring the concentration of cationic electrolytes and the concentration of creatinine, it is disposed of. Therefore, the test strip according to an embodiment of the present invention is a disposable test strip. It is used in conjunction with the non-invasive point-of-care (POC) device according to the present invention for detecting electrolyte imbalance in a patient.

[0091] In a simple embodiment, as used herein, "test strip" refers to a substrate to be contacted with a sample for the quantitative measurement of the concentration of cationic electrolytes and creatinine to be performed. The test strip can take any form suitable for contact with a patient sample, such as a rectangular form, a square form, a circular form or an oval form. In one embodiment, the test strip is planar, having a planar electrically insulating substrate, on which an electrode assembly has been applied. However, in other embodiments, the test strip can also take other shapes and forms, such as a sheet or a rod or a tube, provided that this form is suitable for accommodating a substrate on which an electrode array can be deposited. In one embodiment, the substrate is a planar substrate; in another embodiment, the substrate is a non-planar substrate. For example, it can also be in the form of a sheet or a rod or a tube. In one embodiment, the electrodes of the electrode array are all arranged in a single plane on the substrate, or on the insulating layer if present; in another embodiment, the electrodes do not necessarily have to be in a single plane, but can be arranged in different planes at an angle to each other. The only requirement is that the electrodes are arranged in the electrode array so that they can contact the urine when the test strip is in contact with the urine sample.

[0092] In one embodiment, the test strip according to the invention is itself a separate test strip; in another embodiment, the test strip forms part of an array of test strips, which may be arranged, for example, in a roll or on a tray, wherein one test strip may be used at a time for each measurement. Therefore, the present invention also contemplates and relates to a plurality of test strips according to the invention connected to each other. Therefore, the present invention also relates to an array of test strips according to the invention. In such an array, each test strip is intended for a single use, but the entire array may be used as many times as there are test strips in such an array. In one embodiment, such an array of test strips may be provided in the form of a box or other dispensing device that allows the test strips to be used sequentially. In one embodiment, within such an array, the test strips are detachably connected to each other so that, for example, if the test strip is used for a measurement, it may be separated from the array and used afterwards.

[0093] As used herein, the terms "cation electrolyte selectivity" and "creatinine selectivity" refer to the selectivity of the electrodes or membranes for the corresponding cation electrolytes (e.g., K + , Ca 2+ Mg 2+ 、Zn 2+ Cu 2+) and / or creatinine is a specific and selectively sensitive electrode or membrane. It should be noted that this cation electrolyte selective membrane or electrode is selective for the individual cation electrolyte under consideration, i.e., it is able to distinguish between different cation electrolytes and is selective for one of them (which has been selected by the experimenter). Therefore, K + The selective electrode or membrane is different from the Ca 2+ Selective electrode or membrane. In one embodiment, the specificity and selective sensitivity of the electrode are achieved by applying a cation electrolyte selective membrane or a creatinine selective membrane to the electrode. In one embodiment, this cation electrolyte selective membrane or more generally, an analyte selective membrane is prepared by applying an analyte selective membrane solution to the surface of the corresponding electrode. The application can be completed by dispensing, drop casting, screen printing, spin coating or any other suitable deposition method. This analyte selective membrane solution generally contains analyte-specific carrier molecules, such as ion carriers. The solution also generally contains polymers and solvents. This solution can also and optionally contain other components, such as plasticizers and / or cation exchanger salts. The analyte selective solution can be prepared, for example, by dissolving all components in a suitable solvent. Suitable solvents are various, such as tetrahydrofuran, cyclohexanone or dimethylformamide. Once the analyte selective membrane solution has been applied to the electrode surface, the solvent is removed by drying, evaporation, etc., and what remains is a polymer film containing an analyte-specific and selective carrier.

[0094] The polymer or polymer mixture that can be used to prepare the membrane solution (from which the polymer matrix is ​​generated) and subsequently act as the polymer matrix in the membrane is diverse and, in one embodiment, is selected from polyvinyl chloride, polystyrene, polyacrylates, polycarbonates, polyesters, polyamides, polyurethanes, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohols, polysiloxanes, polymethacrylates (polymetacrylates), silicone elastomers, cellulose esters.

[0095] Fluorinated phases of these polymers are also possible to obtain extremely hydrophobic analyte selective electrode (ASE) membranes, such as ion selective electrode (ISE) membranes.

[0096] In one embodiment, the polymer preferably has a high average molecular weight to ensure the inert character of the membrane.

[0097] In one embodiment, the weight percentage of the polymer material relative to the total weight of the analyte selective membrane is 20% to 40%.

[0098] In one embodiment, one or more plasticizers are included in the film solution. Their effect is to make the film softer and resistant to mechanical stress. In one embodiment, one or more plasticizers that can be used in the film solution can be selected from o-nitrophenyl octyl ether, adipate bis (2-ethylhexyl) ester, sebacate bis (2-ethylhexyl) ester, sebacate dioctyl ester, phosphonic acid dioctylphenyl ester, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, hexamethylphosphoramide, adipate bis (1-butylpentyl) ester, chlorinated paraffin. In one embodiment, the plasticizer is present in an amount sufficient to make the analyte selective carrier become a solvate in the polymer material. In one embodiment, the weight ratio of the plasticizer to the analyte selective carrier is 10: 1 to 100: 1. In one embodiment, the weight ratio of the plasticizer: polymer in a typical plasticizer: polymer mixture is in the range of 1: 1 to 4: 1. In one embodiment, the weight percentage of the plasticizer relative to the gross weight of the film is 40% to 80%.

[0099] Optionally, and in certain embodiments, before the analyte selective solution is applied to the surface of the corresponding electrode, or before the polymer material comprising KCl or a lipophilic salt is applied to the reference electrode, an "inner contact layer" material (also referred to as an ion-electron converter) can be coated on the electrode. Without wishing to be bound by any theory, this inner contact layer has the effect of avoiding the formation of a capacitive layer at the electrode / membrane interface. Examples of materials suitable as "inner contact layers" are conductive polymers, such as polyaniline, poly (3,4-ethylenedioxythiophene), poly (3-octylthiophene), polypyrrole, polyaniline, conductive carbon-based materials, such as graphene, carbon nanotubes, graphene, graphene oxide, reduced graphene oxide or metal nanoparticles. In one embodiment, they can be dissolved or dispersed in a suitable solvent and applied to the surface of the electrode by dispensing, drop casting, screen printing, spin coating or any other suitable deposition method. Once the solution / dispersion has been applied to the electrode surface, the solvent is removed by drying, evaporation, etc., leaving behind the "inner contact layer" to which the analyte selective membrane is then applied.

[0100] In one embodiment, the "inner contact layer" material may also optionally be included directly in the polymer membrane solution of the analyte selective membrane or in the polymer material applied to the reference electrode.

[0101] In some embodiments, although the electrodes should be in electrical contact with a liquid sample, such as a urine sample, it may be advantageous to prevent the electrode array and electrical leads from contacting larger molecules or urine components (e.g., proteins) that may interfere with the quality of one or more concentration determinations and have a negative impact on them. (This deterioration process due to larger molecules is called "biofouling"). Therefore, in some embodiments, optionally, a cover film can be applied to the portion of the test strip that is intended to be in contact with the urine sample. An example of such a suitable cover film is those polycarbonate materials that allow capture of larger interfering molecules, such as those sold under the trademark "Nucleopore".

[0102] Furthermore, in some embodiments, at the end of the manufacture of the test strip, a suitable cover film (e.g., a dielectric protective layer such as a plastic insulating material having openings for the electrodes) can be applied to the test strip ( Figure 4 ) to construct a test strip (2a) having an exposed electrode array 4 and a terminal interface 5 for avoiding contamination of the electrical leads during storage and handling and for commercial use by users.

[0103] It should be noted that in one embodiment, the test strip according to the present invention is not a rod-shaped structure, but a planar electrically insulating substrate or comprises a planar electrically insulating substrate. In one embodiment, the quantitative determination of the cationic electrolyte concentration and the creatinine concentration is not based on colorimetric measurement or current measurement. In one embodiment, it is based on potentiometric measurement. In addition, in one embodiment, the quantitative determination of the cationic electrolyte concentration and the creatinine concentration according to the present invention does not involve the use of enzymes, nor any oxidation / reduction reactions, nor any hydrolysis of the analyte.

[0104] In an embodiment according to the present invention, a disposable test strip is connected to the instant testing device of the present invention for use, and is used to detect electrolyte imbalance. For this purpose, the disposable test strip has a suitable interface for electrically connecting the electrode assembly of the test strip to a readout meter device, which forms a part of the instant testing device of the present invention. This interface can take any suitable form, and in one embodiment, can be a group of electrical contacts from the electrode assembly on a planar substrate. This interface can, for example, take the form of a plug, and the electrical contact forms a part of the plug. The interface is suitable for electrically connecting the electrode assembly to the readout meter device of the non-invasive instant testing device for detecting electrolyte imbalance, wherein this instant testing device includes a readout meter device, and the readout meter device has a receiving module for receiving the interface of the disposable test strip of the present invention, for example, in the form of a recess or a groove or a slit, for receiving the interface of the test strip. In one embodiment, this receiving module can take the form of a socket. Typically, the receiving module is suitable for accommodating the interface of the disposable test strip.

[0105] The term "cation electrolyte concentration in a urine sample" or "in urine" is sometimes abbreviated as "uEl" herein. The same applies to "creatinine concentration in a urine sample" or "in urine", which is abbreviated as "uCrea". The ratio of the cation electrolyte concentration to the creatinine concentration in a urine sample is sometimes abbreviated as "uEl / uCrea" herein.

[0106] As used herein, the abbreviation "EMF" refers to an electromotive force, which essentially refers to the potential difference between two electrodes. This electromotive force is quantitatively related to the corresponding analyte concentration in the sample by the Nernst equation. Typically, the potential signal or measurement value that can be obtained from the test strip according to the present invention is an electromotive force, which can then be related to / converted into an analyte concentration. As used herein, the abbreviation "WE" refers to a working electrode, the abbreviation "RE" refers to a reference electrode, and the abbreviation "NE" refers to a neutral electrode.

[0107] As used herein, the term "cation electrolyte" refers to a non-sodium metal cation electrolyte, and is preferably selected from the group comprising potassium, calcium, magnesium, zinc and copper, preferably selected from the group consisting of potassium, calcium, magnesium, zinc and copper. As used herein, the terms "potassium", "calcium", "magnesium", "zinc" and "copper" refer to the corresponding cationic species of such metals, i.e., K + , Ca 2+ Mg 2 + 、Zn 2+ and Cu 2+As used herein, the term "cation electrolyte" is sometimes also used synonymously with "electrolyte" or "electrolyte of interest". However, it should be understood that such a "cation electrolyte" according to the present invention is not sodium, i.e. neither in its elemental state nor as Na + .

[0108] In one embodiment, the cation electrolyte selective working electrode comprises a cation electrolyte selective membrane comprising a cation electrolyte selective support in a polymer matrix.

[0109] In one embodiment, the cationic electrolyte in "cation electrolyte selectivity" is preferably potassium, and the potassium ion selective carrier is generally a derivative from the antibiotic family, mono-15-crown-5 ether and bis-15-crown-5 ether. Examples of potassium selective carriers are valinomycin, bis[(benzo-15-crown-5)-4'-ylmethyl]pimelate, and bis[(benzo-15-crown-5)-4'-ylmethyl]2-dodecyl-2-methylmalonate, and 2-dodecyl-2-methyl-1,3-propylenebis[N-[5'-nitro(benzo-15-crown-5)-4'-yl]carbamate].

[0110] In one embodiment, the potassium selective carrier molecule may be present in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight, relative to the total weight of the potassium selective membrane.

[0111] In one embodiment, the cationic electrolyte in "cation electrolyte selectivity" is preferably calcium, and the calcium ion selective carrier is generally from the antibiotic family, acyclic diamide derivatives, diazacrown ether rings or phosphates. Examples of calcium selective carriers are 3,6-dioxaoctandiamide, N,N,N',N'-tetracyclohexyl-3-oxaglutaramide, bis[4-(1,1,3,3-tetramethylbutyl)phenyl)]phosphate, dodecyl phosphate, (1,7-bis[2-(1-phenylazo)naphthyl]-1,4,7-trioxaheptane) and bis(octadecyl-3-oxaglutaramide)21-diazacrown ether.

[0112] In one embodiment, the calcium selective carrier molecule may be present in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight, relative to the total weight of the calcium selective membrane.

[0113] In one embodiment, the cationic electrolyte in "cation electrolyte selectivity" is preferably magnesium, and the magnesium ion selective carrier is generally a diamide and a triamide, a β-diketone derivative and a disubstituted diaza crown ether. Examples of magnesium selective carriers are N,N'-diheptyl-N,N'-dimethyl-1,4-succinamide, N,N"-octylene-bis(N'-heptyl-N'-methyl-methylmalonamide, N,N"-octylene-bis(N'-heptyl-N'-methylmalonamide), 4,13-[bis(N-adamantylcarbamoyl)acetyl]-1,7,10,16,tetrahydro-4,13-diazacyclooctadecane and 1,2-bis(ditolylphosphine oxide)benzene)).

[0114] In one embodiment, the magnesium selective carrier molecule may be present in an amount of 0.5 to 10 weight %, preferably 1 to 5 weight %, relative to the total weight of the magnesium selective membrane.

[0115] In another embodiment, the cationic electrolyte in "cation electrolyte selectivity" is preferably copper, and the copper ion selective carrier is generally a derivative from the macrocyclic tetrasulfide, acyclic dithiocarbamate and hydroxamic acid family. Examples of copper ion selective carriers are N-(m-nitrocinnamoyl), N-(p-chlorophenyl)hydroxylamine, N,N,N',N'-tetracyclohexyl-2,2'-thiodiethylamide, o-xylylene-bis(N,N-diisobutyldithiocarbamate), 2-(1,4,8,11-tetrathiacyclotetradec-6-yloxy)hexanoic acid and tetraethylthiuram disulfide.

[0116] In one embodiment, the copper ion selective carrier molecules may be present in an amount of 0.5 to 10 weight %, preferably 1 to 5 weight %, relative to the total weight of the electrolyte selective membrane.

[0117] In another embodiment, the cationic electrolyte in "cation electrolyte selectivity" is preferably zinc, and the zinc ion selective carrier is generally a derivative from the family of alkylated thiuram disulfides and azaglutaric acid diamides. Examples of zinc selective carriers are tetrabutylthiuram disulfide, N-benzyliminodiacetic acid bis(N-ethyl-N-cyclohexylamide) and potassium tris(N-tert-butyl-2-thioxoimidazolyl)borate.

[0118] In one embodiment, the zinc selective carrier molecule may be present in an amount of 1% to 10% by weight, preferably 2% to 6% by weight, relative to the total weight of the electrolyte selective membrane.

[0119] In one embodiment, before the potential measurement, the pH of the sample must be adjusted by adding a suitable buffer to protonate creatinine to form creatinine ions. The term "creatinine selectivity" refers to selectivity for creatinine that does not consider and does not depend on the protonation state of the creatinine. Therefore, the creatinine selective electrode is selective for non-protonated creatinine or protonated creatinine or for both. In one embodiment, the suitable pH is less than 5, and the suitable buffer is various, for example, it can be acetate, citrate or phosphate. Typically, and in one embodiment, the protonated creatinine selective carrier (creatinine selective carrier) can be selected from the crown ether, α-cyclodextrin, β-cyclodextrin, cup pyrrole, aminopyridone and aminopyrimidone family. Examples of creatinine selective carriers are dibenzo-30-crown-10; tri-o-octyl-β-cyclodextrin; 2,6-di-o-dodecyl-β-cyclodextrin; 1-(5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octyl)isocytosine.

[0120] In one embodiment, the creatinine selective carrier can be a crystalline ion pair complex, such as creatinine tungstate phosphate, creatinine molybdate phosphate, or creatinine picrolonate.

[0121] In one embodiment, the creatinine ion selective carrier molecule may be present in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight, relative to the total weight of the creatinine selective membrane.

[0122] In another aspect, the present invention relates to a non-invasive point-of-care (POC) device for detecting electrolyte imbalance in a patient, the POC device comprising:

[0123] A readout meter device for quantitatively and selectively measuring the concentration of cation electrolytes and creatinine in a urine sample, and for determining the ratio of cation electrolytes to creatinine, the readout meter device comprising

[0124] - a multi-channel amplifier, preferably with a high input resistance, for amplifying one or more electrical signals transmitted from a single-use test strip;

[0125] - a controller including an analog / digital converter and storage memory for converting an electrical signal received from a single-use test strip into one or more analyte concentration measurements;

[0126] - a measuring mechanism for initiating and preferably performing a measurement of the analyte concentration;

[0127] - an output device for displaying the concentration measurement value to a user, preferably a display;

[0128] - a receiving module for receiving an interface of a disposable test strip or an interface of a test strip holder unit,

[0129] - optionally, a communication unit, and

[0130] - power supply; and

[0131] an optional test strip holder unit for receiving an interface of a disposable test strip and having an interface for connecting to the receiving module and for establishing electrical contact between the readout meter assembly and the electrode assembly of the disposable test strip, thereby allowing detection and transmission of one or more electrical signals from the disposable test strip to the readout meter assembly, wherein the test strip holder unit has an electrical connector for individually contacting each electrode through the interface of the test strip.

[0132] In one embodiment, the POC device, preferably the readout meter device, further comprises a release mechanism to release the test strip from the receiving module of the readout meter device or from the test strip holder unit if present. In one embodiment, the POC device must include a test strip holder unit. In one embodiment, the measuring mechanism is selected from a measuring button, such as a push button, a press button, a touch button or a digital control button, a joystick, a second pressure point of a button of a POC device or a second press of a button of a POC device, and a voice control device to start the measurement.

[0133] In one embodiment, the POC device further comprises a release mechanism to release the test strip from the receiving module of the readout meter device or from the test strip holder unit if present. In one embodiment, the release mechanism is selected from a button, such as a push button, a twist, a touch button or a digital button, a lever, a second pressure point of a button of a POC device or a second pressure of a button of a POC device, and a voice-controlled release mechanism.

[0134] In one embodiment, the release mechanism is part of the readout meter device, or the release mechanism is part of the test strip holder unit. In one embodiment, the device further includes a user interface for operating the device, and / or a memory for storing multiple electrolyte concentration measurements, and / or a communication unit for transmitting and / or exchanging data with an external computer or an external network, preferably a USB and / or a wireless communication unit. In one embodiment, the device includes ports for both USB connection and wireless connection. In one embodiment, the POC device includes a test strip holder unit and an electrical lead, the test strip holder unit including a main body and at least two terminal interfaces, one for receiving the test strip, and the other for contacting the receiving module of the readout meter device, and the electrical lead is used to electrically connect the digital readout meter device to the disposable test strip.

[0135] In one embodiment, the device further comprises a disposable test strip, which is inserted into the receiving module of the readout meter device or into the test strip holder unit by means of the interface of the disposable test strip, thereby establishing electrical contact between the electrode assembly of the test strip and the readout meter device, wherein preferably, the disposable test strip is a disposable test strip for quantitatively determining the concentration of non-sodium cationic electrolytes and creatinine concentration as further defined above or below herein.

[0136] In one embodiment, the measurement is a potentiometric measurement.

[0137] In one embodiment, quantitative determination of cationic electrolyte concentration and creatinine concentration is performed by one or more potentiometric measurements.

[0138] It should be noted that according to an embodiment of the present invention, the determination of the corresponding concentration of the non-sodium cationic electrolyte and the creatinine concentration is performed "in combination". The term "in combination" means that the concentrations of two analytes in or from one sample (i.e., urine sample) are determined together. However, this does not imply any particular determination order: for example, such determinations can be performed simultaneously or sequentially in a temporally overlapping manner. In one embodiment, the concentrations of the analytes are determined simultaneously, which essentially means that they are determined together without any substantial time interval between their determinations.

[0139] In one embodiment, a test strip according to an embodiment of the invention is a single test strip; in another embodiment, the test strip forms part of an array of test strips, such as may be arranged in a roll or on a tray, wherein one test strip may be used at a time for each measurement.

[0140] In one embodiment, the substrate is a planar substrate; in another embodiment, the substrate is a non-planar substrate. For example, it can also be in the form of a sheet or a rod or a tube. In one embodiment, the electrodes of the electrode array are all arranged in a single plane; in another embodiment, the electrodes do not necessarily all have to be in a single plane, but can be arranged in different planes at an angle to each other. The only requirement is that the electrodes are arranged in the electrode array so that when the test strip is contacted with the urine sample, they can contact the urine.

[0141] In one embodiment, as defined herein, the working electrode, the one or more reference electrodes and the one or more neutral electrodes, if present, have been applied to the substrate or to the electrically insulating layer, if present, by a suitable deposition technique, thereby forming an electrode assembly on the substrate or on the electrically insulating layer. The purpose of the one or more neutral electrodes is to measure and eliminate one or more interferences. However, depending on the type and nature of the one or more interferences, the one or more neutral electrodes may be analyte selective for such interference / interference. In one embodiment, as an example, the one or more neutral electrodes are proton selective and include one or more proton selective membranes. Therefore, although the one or more neutral electrodes are not cation electrolyte selective and are not creatinine selective, they may be selective for other entities (e.g., protons), particularly for these other entities that cause interference.

[0142] In one embodiment, one or more working electrodes may be made of any conductive material, such as carbon, gold, palladium, silver, platinum, titanium, chromium, iridium, tin, their oxides or derivatives and combinations thereof, such as fluorine-doped tin oxide (FTO) or indium tin oxide (ITO). In one embodiment, the one or more electrodes have been applied to the substrate or to the electrically insulating layer if present by a suitable deposition technique (e.g., printing, sputtering, evaporation, electroless plating, affixation, gluing or lithography, preferably screen printing or inkjet printing). The electrodes may be deposited separately or together.

[0143] In one embodiment, the reference electrode(s) are preferably a Ag / AgCl system, but other suitable reference material(s) that provide a controlled potential with the biological fluid are possible and contemplated.

[0144] In one embodiment, the one or more reference electrodes are made of the same material as the working electrode and have a surface coated with a stabilizing layer, such as a conductive polymer such as polyaniline, poly(3,4-ethylenedioxythiophene), poly(3-octylthiophene), polypyrrole or a polymer material such as polyurethane, polyvinyl butyral, polyvinyl chloride, comprising Ag / AgCl / Cl for maintaining a constant potential of the electrode. - system.

[0145] In one embodiment, for higher potential stability, the reference electrode can be additionally coated with a stabilizing layer of a polymeric material including lipophilic salts, such as anion and cation exchange materials (e.g., one or more different tetraalkylammonium and tetraphenylborates). These highly lipophilic components exclude or minimize ion exchange with the sample solution and impart a constant potential to the reference electrode.

[0146] In one embodiment, as already outlined above, the electrode assembly further comprises one or two neutral electrodes (NE) for measuring and eliminating interference. Preferably, such one or more neutral electrodes comprise a membrane comprising a polymer matrix that does not contain any cation electrolyte selective carrier and does not contain any creatinine selective carrier. Typically, the one or more neutral electrodes comprise a polymer matrix that is identical or similar to the polymer matrix in the cation electrolyte selective membrane and / or creatinine selective membrane of the working electrode (WE), but does not include one or more cation electrolyte selective carriers and creatinine selective carriers. The advantage associated with this neutral electrode is that the system introducing this neutral electrode can additionally measure the interference generated by other analytes (e.g., uric acid or ascorbic acid) in the sample. Therefore, as defined herein, although the neutral electrode is not selective for cation electrolytes and is not selective for creatinine, it should be noted that one or more neutral electrodes may be selective for analytes other than cation electrolytes or creatinine as defined herein, such as those analytes or entities that cause possible one or more interferences. In one embodiment, one or more neutral electrodes may be selective for protons. In another embodiment, one or more neutral electrodes may be selective for uric acid and / or ascorbic acid. Each of these neutral electrodes also has an electrical lead, wherein the electrical lead connects each electrode to the interface for electrically connecting the electrode assembly to a readout instrument.

[0147] In one embodiment, each of the electrodes in the electrode assembly has an electrical lead, wherein the electrical lead connects the electrode to the interface for electrically connecting the electrode assembly to a readout instrument. In one embodiment, the electrical lead may be made of any suitable conductive material, such as carbon, gold, palladium, silver, platinum, titanium, chromium, iridium, tin, their oxides or derivatives and combinations thereof, such as FTO, ITO. In one embodiment, the electrical lead has been applied to the substrate or to the electrical insulating layer if present by a suitable deposition technique (e.g., printing, sputtering, evaporation, electroless plating, addition, gluing or lithography, preferably screen printing or inkjet printing). The electrical leads may be deposited separately or together.

[0148] It should be noted that the form and position of the arrangement of both electrodes on the substrate or on the insulating layer if present, (e.g. circular, oval, square, rectangular), is not critical for obtaining usable results from the test strip. Exemplary possible arrangements may be, for example: WE1-WE2-RE, WE1-RE-WE2, or, for example, if a neutral electrode is present, WE1-NE-WE2-RE, WE1-WE2-NE-RE, NE-WE1-WE2-RE, etc. (WE=working electrode; RE=reference electrode; NE=neutral electrode).

[0149] In one embodiment, the joint reference electrode has a surface that is larger than the surface of each of the working electrodes, or each of the individual reference electrodes has a surface that is larger than the surface of each of the working electrodes.

[0150] In one embodiment, the readout meter includes a release mechanism to release the test strip.

[0151] In one embodiment, the readout meter includes a test strip holder, which is optionally removable, for receiving an interface for a test strip.

[0152] In one embodiment, the reader includes a release mechanism to release the test strip from the reader device or from the test strip holder. Fig. 9 , B).

[0153] In one embodiment, the readout meter includes a test strip holder for receiving an interface for a test strip and having a release mechanism ( Fig. 9 , C).

[0154] In one embodiment, the release mechanism is selected from a button, such as a push button, a twist, a touch button or a digital control button, a joystick, a second pressure point of a button of a POC device or a second press of a button of a POC device, and a voice-controlled release mechanism.

[0155] In one embodiment, the release mechanism is part of a readout meter assembly, or the release mechanism is part of a test strip holder unit.

[0156] In one embodiment, the release mechanism is activated after measurement for removing the test strip from the readout meter device or from the test strip holder unit to avoid user contact with the urine sample.

[0157] In one embodiment, the device further comprises a user interface for operating the device, and / or a memory for storing a plurality of analyte concentration measurements, and / or a communication unit, preferably a USB and / or wireless communication unit, for transmitting and / or exchanging data with an external computer or an external network.

[0158] In one embodiment, the device includes ports for USB connection and wireless connection.

[0159] In an embodiment of the method for detecting electrolyte imbalance in a patient, if the ratio of the cation electrolyte concentration to the creatinine concentration in the urine sample is not within the physiologically appropriate ratio value range for the corresponding patient, i.e., above or below the range of the physiologically appropriate ratio value for the corresponding patient, then the electrolyte imbalance is detected. As used herein, the term "physiologically appropriate ratio value range for the corresponding patient" relates to a range of ratio values, i.e., the ratio of the cation electrolyte concentration to the creatinine concentration, which ratio can be measured in a human or animal without electrolyte imbalance. In one embodiment, this physiologically appropriate ratio value range is or has been determined by reference to healthy persons, preferably with reference to healthy persons of the same age, sex, nutrition and / or weight. It is clear to those skilled in the art that this range for healthy patients may be relatively wide. For this physiologically appropriate ratio value range, exemplary but not limiting numerical values ​​are for healthy adult patients:

[0160] Potassium: 5-12; Calcium: 0.05-0.2; Magnesium: >0.25; Zinc: 0.15x10 -3 -1.6x10 -3 ; Copper: 1.2x10 -5 – 12.8x10 -5 .

[0161] As used herein, the term "non-invasive point-of-care (POC) device" relates to a device for quantitative potentiometric determination of non-sodium cation electrolyte concentrations and creatinine concentrations in a patient's urine sample. The POC device of the present invention includes a readout meter device as an analyzer unit for quantitative and selective potentiometric measurement of the concentrations in a urine sample. According to an embodiment of the present invention, the POC device optionally includes a test strip holder unit of the readout meter device that connects the test strip to the POC device. The POC device is optionally combined with a disposable test strip by inserting the test strip holder unit between the readout meter device and the test strip of the POC device, and the disposable test strip serves as a sensing unit for quantitative determination of analytes in urine. In one embodiment, the POC device of the present invention further includes a measuring mechanism and / or a release mechanism. In one embodiment, the measuring mechanism and / or the release mechanism are part of the readout meter device. In another embodiment, the measuring mechanism and / or the release mechanism are part of the test strip holder unit.

[0162] As used herein, the term "readout meter device" relates to a device that is suitable for and configured to quantitatively measure an electrical signal received from a disposable test strip exposed to a sample connected to the readout meter device through a receiving module of the readout meter device, wherein optionally, a test strip holder unit is inserted between the receiving module of the readout meter device and the test strip. The readout meter device according to the present invention is an electrical measuring device, which is a direct reading circuit or a zero-balanced potential circuit. In many embodiments of the present invention, the readout meter device is a multi-purpose digital potentiometric readout meter for quantitatively determining the concentration of cationic electrolytes and the concentration of creatinine in a patient's urine sample. The readout meter device is part of a POC device and is configured to calculate the concentration of the cationic electrolyte and the concentration of the creatinine in the sample based on the electrical signal and calibration information, and is also configured to output, for example, display the results to a user. In one embodiment, the readout meter device includes a measuring unit and an analysis unit, the measuring unit is for example an analog-to-digital converter for converting the electrical signal received from the test strip into a digital value, the analysis unit is for example configured to determine the potential difference in the electrode assembly by the digital value and is configured to calculate the concentration of the cationic electrolyte and the concentration of the creatinine based on such one or more electrical signals. In one embodiment, the calibration information is initially determined for the test strip group and is stored in the analysis unit (e.g., software) to perform the calculation of the analyte concentration later. In one embodiment, the measuring unit is preferably triggered by a measuring mechanism. In some embodiments, in order to apply control to the measurement, a measuring mechanism or a measuring unit or both can be configured for this purpose. In addition, the readout meter device includes an output unit connected to the controller for outputting the result for the user to view. In one embodiment, this readout meter device further includes a communication unit, such as a USB and / or wireless port for exchanging data with an external computer or network. The readout meter device has an interface portion for receiving a test strip or a test strip holder unit. In one embodiment, the readout meter device includes a measuring mechanism and a release mechanism.

[0163] As used herein, the term "receiving module" refers to a receiving module of a meter reading device for receiving an interface of a test strip or a test strip holder unit and for establishing electrical contact between the electrode assembly of the meter reading device and the test strip, thereby allowing one or more electrical signals from the test strip to the meter reading device to be detected and transmitted optionally through the test strip holder unit, wherein the receiving module has an electrical connector for contacting each electrode respectively through the interface of the test strip or the test strip holder unit. In one embodiment, the receiving module is in the form of a slit, a recess or a groove, or other suitable forms that allow connection to be established with the interface of the test strip or the test strip holder unit. In one embodiment, the receiving module can be configured as an edge connector pair or a pin and socket pair. In one embodiment, a disposable test strip according to the present invention is inserted into the receiving module of the meter reading device by means of the interface of the disposable test strip, thereby establishing electrical contact between the electrode assembly of the test strip and the meter reading device. In one embodiment, a disposable test strip according to the present invention is inserted into the test strip holder unit, which is connected to the receiving module of the readout meter device by means of the interface of the disposable test strip, so that electrical contact is established between the electrode assembly of the test strip and the readout meter device through the test strip holder unit. In one embodiment, the readout meter device has a receiving module capable of receiving the interface of a disposable test strip. In one embodiment, the readout meter device has a receiving module capable of receiving the interface of a test strip holder unit. In one embodiment, the readout meter device has a receiving module capable of receiving the interface of a disposable test strip and a receiving module capable of receiving the interface of a test strip holder unit. In one embodiment, the readout meter device has a receiving module capable of receiving the interface of a disposable test strip and a receiving module capable of receiving the interface of a test strip holder unit. In one embodiment, the readout meter device has a receiving module capable of receiving the interface of a disposable test strip and / or a test strip holder unit.

[0164] As used herein, the term "interface" refers to a first interface that is part of a receiving module of a readout meter device, wherein the first interface is capable of establishing contact with a second interface that is part of an optional test strip holder unit that is capable of connecting to the first interface of the receiving module of the readout meter device, and wherein the first interface is capable of establishing contact with an interface of a test strip referred to as a fourth interface. The term also refers to a third interface that is part of a test strip holder unit that is capable of connecting to a fourth interface that is part of a test strip. The fourth interface that is part of the test strip can be connected to the third interface of the test strip holder unit or can also be directly connected to the first interface that is part of the receiving module of the readout meter device.

[0165] As used herein, the term "communication unit" refers to an optional unit of a point-of-care (POC) device for wired and / or wireless transmission of results to a reading unit or network, such as a software application developed for data management and for easy communication between a user and a doctor, or a server connected to a hospital information system (HIS) or a laboratory information system (LIS). In one embodiment, such a communication unit includes a USB port and / or a Bluetooth module.

[0166] As used herein, the term "measuring mechanism" refers to a feature of a POC device for initiating and preferably performing a measurement of a cationic electrolyte concentration and a creatinine concentration in a patient's urine sample. Exemplary measuring mechanisms are measuring buttons, such as a push-down button, a twist, a touch button or a digital button, a joystick, a second pressure point of a different button of the POC device or a second pressure of a button of the POC device, or a voice-controlled device to initiate a measurement. As used herein, the term "measuring mechanism" may also refer to automatically initiating a measurement at a defined time point after a sensing unit senses a sample. In one embodiment, the measuring mechanism preferably operates in conjunction with a measuring unit to perform a measurement.

[0167] As used herein, the term "time-controlled manner" relates to a mechanism for performing measurements, wherein after a measurement has been started, preferably after the measurement has started at a defined time point, a measurement is then performed over a defined time period, wherein the defined time period is a measurement period. In one embodiment, an average value is calculated for the values ​​obtained during the measurement period. In one embodiment, the average value is displayed by a POC device. In one embodiment, the average value is used for subsequent calculations of cation electrolyte concentrations and creatinine concentrations and their ratios, and / or the body status of the cation electrolytes and the creatinine.

[0168] As used herein, the term "measurement button" refers to an exemplary measurement mechanism, which is a button on a POC device that initiates a measurement when pushed (push-down button), pressed (press-twist), or touched (touch button). The term also includes digitally controlled buttons such as button icons displayed on a touch screen.

[0169] When the term "starting measurement" is used in conjunction with a measuring mechanism, the term refers to the action by which a measurement is started at a defined point in time, ie when the measuring mechanism is driven.

[0170] When the term "taking measurements" is used in conjunction with a measuring mechanism, the term refers to an action by which, after the measurement has been started at a defined point in time, the measurement is then performed until the measurement is complete, and this execution includes controlling various measurement parameters, such as the duration of a measurement cycle or the variance of the values ​​of the electrical signal received within the defined measurement cycle. In one embodiment, the measurement is performed in a time-controlled manner. In one embodiment, the measurement is preferably performed by a measuring mechanism as further defined above in combination with a measuring unit. In some embodiments, in order to exert control over the measurement, the measuring mechanism or the measuring unit or both may be configured for this purpose.

[0171] As used herein, the term "release mechanism" refers to a device or mechanism that allows the test strip to be released from the receiving module of the meter device or from the test strip holder unit. An exemplary release mechanism is a button, such as a push button, a press button, a touch button, or a digital button, a control lever, a second pressure point of a button of a POC device or a second press of a button of a POC device, such as a measurement button or a voice-controlled release mechanism. The release mechanism can be a part of the meter device or a part of the test strip holder unit. As used herein, the term "release mechanism" can also refer to automatically releasing the test strip when the measurement is completed.

[0172] As used herein, the term "second pressure point of a button" relates to a feature of a button that has a certain function to also invoke a second, different function, wherein the second, different function can be activated by pressing the button at the second pressure point of the button. For example, a button can be pushed to a defined first level to invoke the first function of the button, and can be pushed to a defined second level to invoke the second function of the button, wherein the first level and the second level are different. For example, the second pressure point of a button can be activated by pressing, pushing, or touching the button at the second pressure point. The term can also relate to a second position of a control lever that allows the second function of the control lever to be activated. The term also includes a second function of a button, wherein the button can be activated to perform different functions, depending on the length of time, for example, of activating the button by pushing, pressing, or touching.

[0173] As used herein, the term "second push button" refers to a feature of a button that has a certain first function to also invoke a second, different function, wherein the second, different function can be activated by pressing the button a second time. The term also includes features of a button where a button can be triggered to invoke different functions depending on how long the button is triggered by pressing, pushing, touching, etc.

[0174] As used herein, the term "voice controlled" relates to a mechanism that allows the POC device to be controlled by voice. Voice control is an optional feature of the POC device that is enabled by an optional voice control unit. In one embodiment, the optional voice control unit can be used to initiate a measurement, i.e., as a measurement mechanism, and / or to release a test strip from a test strip controller unit, i.e., as a release mechanism.

[0175] As used herein, the term "test strip holder unit" refers to a unit that is optionally a part of a POC device according to an embodiment of the present invention and electrically connects a digital readout meter device to a disposable test strip. The test strip holder unit according to the present invention includes electrical leads that allow each electrical lead of a test strip or a test strip array to be connected to a digital readout meter device, respectively. The test strip holder unit further includes an interface portion for receiving a test strip or a test strip array and an interface portion for connecting to a receiving module of the readout meter. By using a release mechanism, the test strip or the test strip array can be released from the test strip holder unit. If necessary, for example, for cleaning, the test strip holder unit is, for example, detachable from the readout meter device by plugging / unplugging. The test strip holder unit can have any size and shape, such as a rectangular shape, a rod-like shape, or a tubular shape. The test strip holder unit has a body that can be rigid or flexible, wherein preferably, for a commodity for use by a user, the body is a rigid body. The test strip holder unit includes at least one interface suitable for connecting to an interface of a disposable test strip or a disposable test strip array, and includes an interface suitable for connecting to a receiving module of a readout meter device. In one embodiment, the test strip holder unit can take the form of a socket or have a rotatable port for connecting to a readout meter device.

[0176] As used herein, the term "potential" relates to the measurement of the potential difference of electrodes, such as the potential difference between a reference electrode and an analyte-selective working electrode under zero (or negligible) current conditions. Potential measurements do not involve the measurement of current, and do not involve the use of enzymes and the measurement of enzymatic reaction products, nor do quantitative measurements involve any chemical reactions (e.g., oxidation / reduction reactions) or any hydrolysis of the analyte. The measurements performed with the POC device of the present invention and the test strips according to the present invention are potentiometric measurements. The potentiometric measurements according to the present invention are not based on colorimetric or amperometric measurements. Typically, the potential signal or measurement value that can be obtained from the test strips according to the present invention is an electromotive force, which can then be associated / converted into an analyte concentration.

[0177] In one embodiment, as used herein, the term "potentiometric measurement" relates to measuring the analyte concentration by the potential difference between an analyte-selective working electrode and a reference electrode of a test strip, wherein the reference electrode has a constant potential and the analyte-selective working electrode has a potential that follows a Nernst linear development related to the amount of said analyte in the sample. In one embodiment, such measurement is performed by contacting a disposable potentiometric test strip in contact or contacted with a urine sample directly or through a test strip holder unit with a digital readout meter device of the POC device of the present invention, thereby measuring the potential difference between the two electrodes, amplifying the signal and converting the resulting analog signal into a digital signal.

[0178] As used herein, the term "deficiency" relates to a disorder of the human or animal body characterized by a pathological decrease, ie a deficiency, of a certain analyte in the body. The deficiency may result from a low uptake of this analyte or an increased loss of this analyte.

[0179] As used herein, the term "overload" relates to a disorder of the human or animal body characterized by a pathological increase, ie, overload, of an analyte in the body. The overload may result from a high uptake of this analyte or a reduced loss of this analyte.

[0180] As used herein, the term "physiologically appropriate value" or "physiologically appropriate value for a patient" relates to a value of an analyte concentration or a value of an analyte concentration ratio that is within the range of values ​​that can be measured in a human or animal without a deficiency or overload of the analyte. In one embodiment, such a physiologically appropriate value may depend on the constitution of the human or animal. In one embodiment, such a physiologically appropriate value may depend on the age, sex, health status or nutritional status of the human or animal. BRIEF DESCRIPTION OF THE DRAWINGS

[0181] The present invention will now be further described with reference to the following drawings, in which:

[0182] Figure 1Schematic diagram showing one embodiment of a point-of-care (POC) device for detecting electrolyte deficiency and / or overload in a patient; EMF = electromotive force; uEl = concentration of cationic electrolytes in a urine sample (El = K + , Ca 2+ ,Mg 2 + , Zn 2+ , Cu 2+ ); uCrea = creatinine concentration in urine sample; uEl / uCrea = cation electrolyte:creatinine concentration ratio. 1 = POC device, 2 = test strip, 3 = readout meter device, 4 = electrode assembly, 5 = interface for electrical connection, 6 = cation electrolyte selective electrode, 7 = creatinine selective electrode, 8 = reference electrode, 9 = electrical leads.

[0183] Figure 2 A top view of an exemplary test strip is shown having an array of electrodes and electrical leads applied to an insulating layer in exemplary possible patterns.

[0184] A) Exemplary circular working electrode + circular reference electrode

[0185] 5 = Interface for electrical connection

[0186] 6 = Cation electrolyte selective electrode

[0187] 7 = Creatinine selective electrode

[0188] 8 = Reference electrode

[0189] 9 = Electrical leads

[0190] B) Exemplary circular working electrode + elliptical reference electrode

[0191] C) Exemplary circular working electrode + rectangular reference electrode

[0192] D) Exemplary square-shaped working electrode + rectangular reference electrode

[0193] E) 9a) = Exemplary contact path at the end of the electrical lead for contacting the readout instrument device

[0194] F) 10 = Neutral electrode for interference determination

[0195] Figure 3 A cross-sectional view of an exemplary analyte-selective electrode is shown.

[0196] A) No "internal contact layer"

[0197] 11 = base

[0198] 12=Insulation layer

[0199] 13 = Conductive layer

[0200] 14 = Analyte selective membrane

[0201] B) has an "internal contact layer"

[0202] 15 = Optionally, "Inner Contact" (Transducer)

[0203] C) has a "covering layer" and

[0204] 16 = Optionally, "covering layer"

[0205] Figure 4 An exemplary embodiment for manufacturing an exemplary test strip having an additional cover layer is shown. In such an exemplary manufacturing method, the following steps are performed:

[0206] Step 1) Place an insulating layer on top of the substrate

[0207] Step 2) Applying electrode assembly and electrical leads

[0208] Step 3) Forming an analyte selective electrode

[0209] Step 4) Preferably, a suitable covering film is applied, such as a plastic insulating material having openings for the electrodes.

[0210] 2a = Test strip with cover

[0211] 4a = Electrode assembly and electrical leads

[0212] 5 = Interface for electrical connection

[0213] 11a = substrate with insulating layer

[0214] 15a = Analyte selective membrane solution

[0215] 16 = Covering layer with openings for electrodes

[0216] Figure 5 The test strips (K1-K4) prepared according to the present invention are shown for different potassium (K + ) concentration.

[0217] Figure 6 The results show that the test strips (Ca1-Ca4) prepared according to the exemplary embodiment of the present invention react with different calcium (Ca 2+ ) concentration.

[0218] Figure 7The potentiometric responses of test strips (Crea1-Crea4) manufactured according to an exemplary embodiment of the present invention to different concentrations of protonated creatinine in aqueous solution are shown.

[0219] Figure 8 A top view of an exemplary test strip is shown with an electrode array and substrate of exemplary dimensions. WE1 = first working electrode; WE2 = second working electrode; RE = reference electrode.

[0220] Fig. 9 An exemplary embodiment of a point-of-care (POC) device for detecting electrolyte deficiency and / or electrolyte overload in a patient is shown, consisting of:

[0221] A) Test strip and readout meter with release button (17a)

[0222] B) Test strip and readout meter equipped with test strip holder (18) and release button (17a)

[0223] C) A test strip and a readout meter equipped with a test strip holder (18), wherein the test strip holder has a release button in the form of a lever (17b)

[0224] Fig.10 An exemplary point-of-care (POC) device for detecting electrolyte deficiency and / or electrolyte overload in a patient consisting of a test strip and a readout meter displaying exemplary analysis results is shown.

[0225] Fig.11 A prototype of a (POC) device according to an embodiment of the present invention is shown.

[0226] Panel A shows a (POC) device comprising a single-use test strip connected to a readout meter device via a test strip holder unit, ready for measurement;

[0227] Panel B shows a (POC) device in which the test strip contacts the urine sample and the measurement is initiated in a "time-controlled manner" after the measuring mechanism has been activated;

[0228] Panel C shows the POC device after measurement, wherein the result just after the measurement is displayed by the output unit (ie, display) of the readout meter to which the disposable test strip is connected via the test strip holder unit. DETAILED DESCRIPTION

[0229] Furthermore, the present invention will now be further described by reference to the following examples which are given by way of illustration and not limitation of the present invention.

[0230] Example

[0231] Example 1

[0232] Test strip structure

[0233] For proof of principle experiments, a test strip according to the present invention having an electrode array of the demonstrated size was fabricated. The device consists of a carbon working electrode (WE), a (Ag / AgCl) counter electrode / reference electrode (RE), electrical leads screen-printed on a plastic substrate, and an interface for electrical connection to a readout instrument.

[0234] Example 2

[0235] Manufacturing of Potassium Selective Test Strips

[0236] To obtain a potassium selective electrode (K-ISE), a solution of poly(3-octylthiophene) in tetrahydrofuran (0.5 mg / 1 mL) was poured (2.5 μL) on an area of ​​the carbon WE of the test strip of Example 1. The substrate was then dried to remove the solvent, forming a thin converter layer. Subsequently, a solution of a potassium selective membrane (K-ISM) solution (3,5 μL) was poured on top of the above converter layer. The substrate was then dried to remove the solvent, forming a potassium selective membrane on the WE. The K-ISM solution consisted of a mixture of 2.0 mg of the potassium ionophore valinomycin, 0.5 mg of potassium tetrakis(4-chlorophenyl)borate, 32.8 mg of PVC (high molecular weight polyvinyl chloride) and 64.7 mg of bis(2-ethylhexyl) sebacate in 1 mL of tetrahydrofuran.

[0237] Example 3

[0238] Potentiometric measurements with potassium selective test strips

[0239] The potassium selective test strip is immersed in the sample solution until all electrodes are covered and the potential difference (EMF) between the modified WE and RE is measured with a high input impedance voltmeter integrated in a prototype readout meter having a receiving module for an interface to receive the test strip and a display on which the results are immediately displayed.

[0240] Example 4

[0241] Sensor calibration by measuring a series of standard potassium solutions

[0242] Potassium chloride (KCl) was prepared by dissolving it in water with a potassium concentration of 1 M, 10 -1 M, 10 -2 M, 10 -3 The EMF values ​​were recorded and a calibration curve was constructed by plotting the EMF values ​​as a function of the negative logarithm of the potassium concentration. Four different test strips (K1–K4) were manufactured and tested. The results are summarized in Table 1.

[0243] Table 1 EMF values ​​for four different potassium concentrations (1.0–0.001 M) obtained by measuring with four different test strips (K1–K4).

[0244]

[0245] The data clearly show good reproducibility and - as Figure 5 As shown in - the linear (dynamic) range is between 0.001 M and 1 M potassium solutions. Thus, the linear range of the test strip covers medically relevant concentrations in physiological solutions, such as in human urine, where the range for potassium concentrations is typically between 0.025-0.125 M.

[0246] From these data, for each test strip a regression equation of type

[0247] EMF = slope x(-log[K + ])+intercept,

[0248] Their mean values ​​and deviations were calculated (Table 2).

[0249] Table 2 Overview of linear regression equations and correlation coefficients obtained for EMF measurements with four different sodium sensors (K1–K4); slopes are expressed as [mV / (-log[K + ])], intercept is expressed in [mV], R 2 =Determination coefficient.

[0250] Test strips Slope intercept <![CDATA[R 2 ]]> K1 -105,3 202,7 0,9995 K2 -104,5 204,0 0,9999 K3 -105,6 208,0 0,9998 K4 -105,1 210,4 0,9997 average value -105,1 206,3 0,9997 Deviation value 0,4 3,1 0,0002

[0251] Using these regression equations, the potassium concentration in a sample can be determined from the measured EMF as illustrated in the following example:

[0252] Measured sample EMF: 2.0mV

[0253] Regression equation (average): EMF = -105.1 (-log [K]) + 206.3

[0254] but

[0255] -log[K + ] = (2-206.3) / (-105.1) = 1,9439

[0256] [K + ]=10 -1.9439 =0.0114M=11.4mM

[0257] Example 5

[0258] Fabrication of calcium selective test strips

[0259] To obtain a calcium selective electrode (Ca-ISE), a solution of poly(3-octylthiophene) in tetrahydrofuran (0.5 mg / 1 mL) was cast (2.5 μL) on an area of ​​the carbon WE. The substrate was then dried to remove the solvent, forming a thin transducer layer. Subsequently, a solution of calcium selective membrane (Ca-ISM) solution (3,5 μL) was cast on top of the above transducer layer. The substrate was then dried to remove the solvent to form a calcium selective membrane on the WE. The Ca-ISM solution consisted of a mixture of 2.0 mg calcium ionophore II (N,N,N′,N′-tetra[cyclohexyl]diglycolic acid diamide), 0.5 mg potassium tetrakis(4-chlorophenyl)borate, 32.8 mg PVC (high molecular weight polyvinyl chloride) and 64.7 mg of 2-nitrophenyl octyl ether in 1 mL of tetrahydrofuran.

[0260] Example 6

[0261] Potentiometric measurements with calcium-selective test strips

[0262] The calcium selective test strip is immersed in the sample solution until all electrodes are covered and the potential difference (EMF) between the modified WE and RE is measured with a high input impedance voltmeter integrated in a prototype readout meter having a receiving module for an interface to receive the test strip and a display on which the results are immediately displayed.

[0263] Example 7

[0264] Sensor calibration by measuring a series of standard calcium solutions

[0265] By adding calcium chloride (CaCl 2 ) were dissolved in water to prepare calcium concentrations of 10 -1 M, 5x10 -2 M, 10 -2 M, 5x10 -3 The EMF values ​​were recorded and a calibration curve was constructed by plotting the EMF values ​​as a function of the negative logarithm of the calcium concentration. Four different test strips (Ca1–Ca4) were manufactured and tested. The results are summarized in Table 3.

[0266] Table 3 EMF values ​​for four different calcium concentrations (0.1–0.005 M) obtained by measuring with four different test strips (Ca1–Ca4).

[0267]

[0268] The data clearly show good reproducibility and - as Figure 6As shown in - the linear (dynamic) range is between 0.005 M and 0.1 M calcium solutions. Thus, the linear range of the test strip covers medically relevant concentrations in physiological solutions, such as in human urine, where calcium concentrations are typically in the range of about 10 mM.

[0269] From these data, for each test strip a regression equation of type

[0270] EMF = slope x (-log [Ca 2+ ])+intercept,

[0271] Their mean values ​​and deviations were calculated (Table 4).

[0272] Table 4 Overview of linear regression equations and correlation coefficients obtained for EMF measurements using four different sodium sensors (Ca1–Ca4); slopes are expressed as [mV / (-log[Ca 2+ ])], intercept is expressed in [mV], R 2 =Determination coefficient.

[0273] Test strips Slope intercept <![CDATA[R 2 <!-- 23 -->]]> Ca1 -54,6 282,6 0,9966 Ca2 -56,5 284,4 0,9945 Ca3 -55,2 283,1 0,9966 Ca4 -55,0 279,7 0,9957 average value -55,3 282,4 0,9959 Deviation value 0,7 1,7 0,0009

[0274] Using these regression equations, the potassium concentration in a sample can be determined from the measured EMF as illustrated in the following example:

[0275] Measured sample EMF: 155.0mV

[0276] Regression equation (average): EMF = -55.3 (-log [Ca 2+ ])+282.4

[0277] but

[0278] -log[Ca 2+ ]=(155-282.4) / (-55.3)=2,3038

[0279] [Ca + ]=10 -2,3038 =0.00498M=4.98mM

[0280] Example 8

[0281] Creatinine selective test strip manufacturing

[0282] To obtain a creatinine selective electrode (Crea-ISE), a solution of poly(3-octylthiophene) in tetrahydrofuran (0.5 mg / 1 mL) was cast (2.5 μL) on an area of ​​the carbon WE. The substrate was then dried to remove the solvent, forming a thin converter layer on the surface. Subsequently, a solution (3,5 μL) of a creatinine selective membrane (Crea-ISM) solution was cast on top of the above converter layer. The substrate was then dried to remove the solvent to form a creatinine selective membrane on the WE. The Crea-ISM solution consisted of a mixture of 4.0 mg creatinine molybdate phosphate, 63 mg PVC (high molecular weight polyvinyl chloride) and 125 mg o-nitrophenyl octyl ether in a mixture of 2 mL tetrahydrofuran and 0.5 mL acetone.

[0283] Example 9

[0284] Potentiometric measurements with creatinine selective test strips

[0285] The creatinine selective test strip is immersed in the sample solution until all electrodes are covered and the potential difference (EMF) between the modified WE and RE is measured with a high input impedance voltmeter integrated in a prototype readout meter having a receiving module for an interface to receive the test strip and a display on which the results are immediately displayed.

[0286] Example 10

[0287] Sensor calibration by measuring a series of standard creatinine solutions

[0288] The creatinine concentrations of 1 M, 316.2 x 10 -1 M, 17.8x10 -1 M, 10 -1 M, 3.16x10 -2 M, 10 -2 M, 10 -3 The EMF values ​​were recorded and a calibration curve was constructed by plotting the EMF values ​​as a function of the negative logarithm of the potassium concentration. Four different test strips (Crea1–Crea2) were manufactured and tested. The results are summarized in Table 5.

[0289] Table 5 EMF values ​​for seven different creatinine concentrations (1.0–0.001 M) obtained by measuring with four different test strips (Crea1–Crea4).

[0290]

[0291] The data clearly show good reproducibility and - as Figure 7As shown in - the linear (dynamic) range is between 0.001 M and 1 M creatinine solutions. Thus, the linear range of the test strip covers medically relevant concentrations in physiological solutions, such as in human urine, where the range for creatinine concentrations is typically about 1-32 mM.

[0292] From these data, for each test strip a regression equation of type

[0293] EMF = slope x (-log [Crea]) + intercept,

[0294] Their mean values ​​and deviations were calculated (Table 6).

[0295] Table 6 Overview of linear regression equations and correlation coefficients obtained for EMF measurements with four different sodium sensors (Crea1–Crea4); slopes are expressed in [mV / (-log[Crea])], intercepts are expressed in [mV], R 2 =Determination coefficient.

[0296] Test strips Slope intercept <![CDATA[R 2 ]]> Crea1 -109,8 366,1 0,9995 Crea2 -110,4 356,6 0,9997 Crea3 -109,0 352,1 0,9996 Crea4 -108,7 363,1 0,9988 average value -109,8 358,3 0,9996 Deviation value 0,6 5,8 0,0001

[0297] Using these regression equations, the potassium concentration in a sample can be determined from the measured EMF as illustrated in the following example:

[0298] Measured sample EMF: 140.0mV

[0299] Regression equation (average): EMF = -109.8 (-log [Crea]) + 358,3

[0300] but

[0301] -log[Crea]=(140.0-358.3) / (-109.8)=1,9882

[0302] [Crea] = 10 -1.9882 =0.01027M=10.3mM

[0303] References

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[0327] The features of the invention disclosed in the description, the claims and / or the drawings, both individually and in any combination thereof, are material for realizing the invention in its various forms.

Claims

1. A disposable test strip for the quantitative potentiometric determination of the concentration of non-sodium cationic electrolytes and creatinine in a patient's urine sample, The test strip comprises: a substrate which is electrically insulating or has an electrically insulating layer applied thereto, - an electrode assembly applied to the substrate or to the electrically insulating layer, The electrode assembly at least includes - a working electrode selective for said cationic electrolyte; - a creatinine selective working electrode; - a joint reference electrode for both the cation electrolyte selective working electrode and the creatinine selective working electrode, or a reference electrode for the cation electrolyte selective working electrode and a separate reference electrode for the creatinine selective working electrode; - Optionally; one or two neutral electrodes for measuring and eliminating interference; - an interface for electrically connecting the electrode assembly to a readout instrument.

2. A disposable test strip according to claim 1, wherein the working electrode, the reference electrode and the optional neutral electrode have been applied to the substrate or to the electrically insulating layer by a suitable deposition technique to form an electrode assembly on the substrate or on the electrically insulating layer, and wherein the cation electrolyte selective working electrode comprises a cation electrolyte selective membrane, and the creatinine selective working electrode comprises a creatinine selective membrane, and wherein the optional neutral electrode comprises a membrane that is not selective for the cationic electrolyte and is not selective for creatinine.

3. A disposable test strip according to claim 2, wherein the deposition technique is printing, sputtering, evaporation, electroless plating, attaching or gluing.

4. A single-use test strip according to claim 3, wherein the deposition technique is screen printing, inkjet printing or lithographic printing.

5. A disposable test strip according to any one of claims 1 to 4, wherein the non-sodium cationic electrolyte is selected from the group consisting of potassium, calcium, magnesium, zinc and copper.

6. The disposable test strip of claim 5, wherein the non-sodium cationic electrolyte is selected from the group consisting of potassium, calcium, magnesium, zinc and copper.

7. A disposable test strip according to claim 1, wherein the substrate is made of a material selected from the group consisting of plastic, ceramic, alumina, paper, rubber, fabric, carbon-based polymers, fluoropolymers, silicon-based substrates, semiconductor materials, and dielectric materials; and wherein the electrical insulating layer is made of a dielectric material, wherein, If the electrically insulating layer is present on the substrate, the electrode assembly is located on the electrically insulating layer.

8. A disposable test strip according to claim 7, wherein the paper is cardboard; the carbon-based polymer is polypropylene; the fluoropolymer is Teflon; the silicon-based substrate is a silicon-based polymer, glass, quartz, silicon nitride or silicon oxide; the semiconductor material is elemental silicon; the dielectric material is an organic dielectric material selected from polyimide, polycarbonate, polyvinyl chloride, polystyrene, polyethylene, polypropylene, polyester, polyethylene terephthalate, polyurethane, polyvinylidene fluoride, or the dielectric material is an inorganic dielectric material.

9. The disposable test strip of claim 8, wherein the silicon-based polymer is polydimethoxysiloxane; or, wherein the inorganic dielectric material is silicon dioxide.

10. A disposable test strip according to claim 2, wherein the cation electrolyte selective working electrode comprises a cation electrolyte selective membrane comprising a cation electrolyte selective carrier in a polymer matrix, and the creatinine selective membrane comprises a creatinine selective carrier in a polymer matrix.

11. The disposable test strip according to claim 1, wherein the electrode assembly further comprises one or two neutral electrodes for measuring and eliminating interference, wherein the neutral electrode comprises a membrane comprising a polymer matrix free of any cationic electrolyte selective carrier and free of any creatinine selective carrier.

12. The disposable test strip of claim 1, wherein each of the electrodes in the electrode assembly has an electrical lead, wherein the electrical lead connects the electrode to the interface to electrically connect the electrode assembly to a readout meter device.

13. A single-use test strip according to claim 1, wherein the combined reference electrode has a surface larger than the surface of each of the working electrodes, or each of the individual reference electrodes has a surface larger than the surface of each of the working electrodes.

14. A non-invasive point-of-care testing device for detecting electrolyte imbalance in a patient, the point-of-care testing device comprising: - a readout meter device for quantitatively and selectively potentiometrically measuring the concentration of cation electrolytes and creatinine in a urine sample, and for determining the ratio of cation electrolytes to creatinine, the readout meter device comprising - a receiving module for receiving an interface of a disposable test strip according to any one of claims 1 to 13 and for establishing electrical contact between the readout meter device and an electrode assembly of the disposable test strip, thereby allowing detection and transmission of one or more electrical signals from the disposable test strip to the readout meter device, wherein the receiving module has a plurality of electrical connectors for contacting each electrode respectively through the interface of the test strip; - a multi-channel amplifier having a high input resistance for amplifying one or more electrical signals transmitted from a single-use test strip according to any one of claims 1 to 13; - a controller including an analog / digital converter and a storage memory for converting an electrical signal received from a single-use test strip according to any one of claims 1 to 13 into one or more cationic electrolyte concentration measurements and one or more creatinine concentration measurements, and for subsequently determining a ratio of cationic electrolyte concentration to creatinine concentration based on the cationic electrolyte concentration measurements and the creatinine concentration measurements; - output means for displaying the concentration measurements and / or said ratio to a user, and -power supply.

15. The non-invasive point-of-care testing device of claim 14, wherein the output device is a display.

16. The non-invasive point-of-care testing device according to claim 14, further comprising - A disposable test strip according to claim 1, which is inserted into the receiving module of the readout meter device by means of the interface of the disposable test strip, thereby establishing electrical contact between the electrode assembly of the test strip and the readout meter device.

17. The non-invasive point-of-care testing device according to any one of claims 14 to 16, wherein the device further comprises - a user interface for operating the device, and / or a memory for storing a plurality of cation electrolyte concentration measurements and creatinine concentration measurements and the determined ratio of cation electrolyte concentration to creatinine concentration, and / or a connection interface.

18. The non-invasive point-of-care testing device according to claim 17, wherein the connection interface is a USB connection interface and / or a wireless connection interface for transmitting and / or exchanging data with an external computer or an external network.

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