Analyte test system for determining the concentration of an analyte in a physiological or aqueous fluid

Abstract

This invention provides a device for determining the concentration of an analyte like glucose, cholesterol, free fatty acids, triglycerides, proteins, ketones, phenylalanine or enzymes, in a physiological or aqueous fluid like blood, serum, plasma, saliva, urine, interstitial and/or intra-cellular fluid, the device having an integrated calibration and quality control system suitable for dry reagent test strips with a very small sample volume of about 0.5 μL based on to a new sample distribution system. The production of the inventive analyte test element involves only a small number of uncomplicated production steps enabling an inexpensive production of the strips.

1 . An analyte test element for determining the concentration of at least one analyte in a physiological or aqueous sample fluid having a first surface ( 2   a ) and a second surface ( 4   a ) in a predetermined distance opposite from each other, said both surfaces are provided with two substantially equivalent patterns forming areas of high and low surface energy which are aligned mostly congruent to create a sample distribution system ( 6 ) with at least two detection areas ( 6   a ), wherein the applied physiological or aqueous fluid is substantially constrained to the areas with high surface energy. 
     
     
         2 . The analyte test element according to  claim 1 , wherein the distance between the first and second surface is determined by a centre layer ( 3 ) which is arranged between a base layer ( 2 ) and a cover layer ( 4 ) having the first and second surfaces ( 2   a ,  4   a ). 
     
     
         3 . The analyte test element according to  claim 2 , wherein the centre layer ( 3 ) has a discontinuity ( 5 ) to form a hollow cavity together with the first and second surface ( 2   a,    4   a ) of the base and cover layer ( 2 ,  4 ), said hollow cavity being larger than the sample distribution system ( 6 ) formed by the areas of high surface energy on the first and second surfaces ( 2   a ,  4   a ). 
     
     
         4 . The analyte test element according to  claim 1 , wherein said areas of high surface energy are created by applying cross-linkable and/or non-soluble hydrophilic and/or amphiphilic agents on the first and second surfaces ( 2   a,    4   a ). 
     
     
         5 . The analyte test element according to  claim 4 , wherein said hydrophilic agents are selected from the group consisting of functionalised derivates from polyalcohols, polyethylene-glycols, polyethylene-oxides, vinylpyrrolidones and organo-modified polysiloxanes or alkyl-phosphocholine polyethylene-glycol copolymers. 
     
     
         6 . The analyte test element according to  claim 1 , wherein said first surface ( 2   a ) and second surface ( 4   a ) are hydrophobic and non-wettable by a physiological or aqueous fluid and transparent for light particular in the UV, near IR and/or visible range of the electromagnetic spectrum. 
     
     
         7 . The analyte test element according to  claim 1 , wherein said areas of low surface energy are created by applying a hydrophobic composition on the first and second surfaces ( 2   a ,  4   a ), said hydrophobic composition preventing the wetting of the coated area by a physiological or aqueous fluid. 
     
     
         8 . The analyte test element according to  claim 7 , wherein said hydrophobic composition contains isooctyl acrylates, dodecyl acrylates, styrene derivates, or systems with partly fluorinated carbon chains. 
     
     
         9 . The analyte test element according to  claim 7 , wherein said first surface ( 2   a ) and second surfaces ( 4   a ) are hydrophilic and wettable for the physiological or aqueous fluid and transparent for light particular in the UV, near IR and/or visible range of the electromagnetic spectrum. 
     
     
         10 . The analyte test element according to  claim 9 , wherein said first surface ( 2   a ) and second surface ( 4   a ) are rendered hydrophilic by physical or chemical vapour deposition of hydrophilic compounds. 
     
     
         11 . The analyte test element according to  claim 1 , wherein the base layer ( 2 ) and cover layer ( 4 ) providing the first and second surfaces ( 2   a,    4   a ) are formed of a material selected from the group consisting of glass, polyvinyl acetate, poly-methyl-methacrylate, poly-dimethyl-siloxane, polyesters and polyester resins containing fluorene rings, polycarbonates and polycarbonate-polystyrene graft copolymers, terminal modified polycarbonates, polyolefins, cycloolefins and cycloolefin copolymers, and/or olefin-maleimide copolymers. 
     
     
         12 . The analyte test element according to  claim 1 , wherein
 n predetermined detection areas ( 6 ′ a ) of said first surface ( 2   a ) are coated with a catalytic formulation promoting the detection of an analyte in a physiological or aqueous fluid, and   n predetermined detection areas ( 6   a ) of said second surface ( 4   a ) are coated with n calibration formulations made up of m blank formulations and n−m formulations, with different levels of calibration compound, whereby n is an integer number larger than 2, m is an integer number equal or larger than 1, and n>m.   
     
     
         13 . The analyte test element according to  claim 12 , wherein an additionally detection area ( 6   c ) is provided which neither contains the catalytic compound nor the calibration compound, enabling the measurement of background signals. 
     
     
         14 . The analyte test element according to  claim 12 , wherein said catalytic formulation coated on n predetermined detection areas ( 6 ′ a ) of first surface ( 2   a ) allows the detection of an analyte concentration contained in a physiological or aqueous fluid sample using transmission or absorbance photometry. 
     
     
         15 . The analyte test element according to  claim 12 , wherein said calibration compound contained in the calibration formulation coated on n−m predetermined detection areas ( 6   a ) of second surface ( 4   a ) is identical or substantially equivalent to the analyte and able to induce the same chemical reaction in the catalytic formulation as the analyte in the physiological or aqueous fluid sample. 
     
     
         16 . The analyte test element according to  claim 15 , wherein the calibration compound is glucose. 
     
     
         17 . The analyte test element according to  claim 12 , wherein the catalytic formulation contains as reactive components a promoter undergoing a catalytic or non-catalytic reaction with the analyte, and/or a co-enzyme, and an indicator generating an optically detectable product. 
     
     
         18 . The analyte test element according to  claim 17 , wherein the promoter is an enzyme selected from the group consisting of dehydrogenases, kinases, oxidases, phosphatases, reductases and/or transferases. 
     
     
         19 . The analyte test element according to  claim 18 , wherein the promoter is an enzyme specific for glucose. 
     
     
         20 . The analyte test element according to  claim 17 , wherein the indicator to determine the analyte concentration is selected from the group consisting of aromatic amines, aromatic alcohols, azines, benzidines, hydrazones, aminoantipyrines, conjugated amines, conjugated alcohols, and/or aromatic and aliphatic aldehydes. 
     
     
         21 . The analyte test element according to  claim 12 , wherein the calibration formulation applied to the predetermined detection areas ( 6   a ) of second surface ( 4   a ) contains an inert water-soluble dye in a predetermined and fixed ratio to the calibration compound allowing a suitable reading device to evaluate the concentration of the calibration compound within the calibration formulation with a wave length different from the wave length used to measure the reaction product of the catalytic formulation with the analyte. 
     
     
         22 . The analyte test element according to  claim 21 , wherein said inert water-soluble dye is selected from the group consisting of brilliant black BN; brilliant blue G; carmoisine; coumarin 120; direct blue 2B; indigo carmine; new coccine; ponceau 4R; rhodamine 19; sunset yellow; tartrazine; and/or a water soluble derivate of malachite green. 
     
     
         23 . The analyte test element according to  claim 1 , wherein a sample application area ( 9 ) is located at the end of a convex and lateral extension ( 10 ) on one side of said analyte test element. 
     
     
         24 . An analyte test arrangement including a plurality of devices according to  claim 1 , which are arranged symmetrically around a centre point to form an analyte test disk ( 31 ) with outward facing sample application areas ( 39 ). 
     
     
         25 . An analyte test arrangement including a plurality of devices according to  claim 1 , which are arranged in a linear manner to form an analyte test bandolier ( 44 ) with lateral extensions forming the sample application areas ( 9 ). 
     
     
         26 . A method for preparing an analyte test element comprising the steps:
 applying areas of high and low surface energy on a base layer ( 2 ) having a first surface ( 2   a ), the areas of high surface energy forming a hydrophilic path with a predetermined detection areas ( 6 ′ a ), whereby n is an integer number equal or larger than 2,   applying a corresponding pattern of areas of high and low surface energy on a cover layer ( 4 ) having a second surface ( 4   a ),   coating a catalytic formulation on the .n detection areas ( 6 ′ a ) of the first surface ( 2   a ), said catalytic formulation promoting the detection of an analyte concentration contained in a physiological or aqueous fluid sample using transmission or absorbance photometry,   coating n calibration formulations on n detection areas, ( 6   a ) of the second surface ( 4   a ), said n calibration formulations made up of m blank formulations and n−m formulations with different levels of calibration compound, whereby m is an integer number of at least 1, and n>m, which is identical or substantially equivalent to the analyte and able to induce the same chemical reaction in the catalytic formulation as the analyte in the physiological or aqueous fluid sample,   laminating the layers of first and second surfaces to the opposite sites of a centre layer ( 3 ) having a discontinuity ( 5 ) which provides a cavity for the sample distribution system ( 6 ) formed by the areas of high surface energy on the first and second surfaces of the base and cover layer,   punching or cutting the laminated sheets to the final shape.   
     
     
         27 . A method for preparing an analyte test element according to  claim 26 , wherein said areas of high surface energy are created by applying cross-linkable and/or non-soluble hydrophilic and/or amphiphilic agents on the first and second surfaces, said hydrophilic and/or amphiphilic agents. 
     
     
         28 . A method for preparing an analyte test element according to  claim 27 , wherein said areas of high surface energy are printed on the first and second surface by the means of flexography, lithography, gravure, solid ink coating methods, or ink-jet-printing. 
     
     
         29 . A method for preparing an analyte test element according to  claim 26 , wherein said areas of low surface energy are created by applying a hydrophobic compound on the first and second surfaces, said hydrophobic compound preventing the wetting of the coated area by a physiological or aqueous fluid. 
     
     
         30 . A method for preparing an analyte test element according to  claim 29 , wherein said first and second surfaces are rendered hydrophilic by physical or chemical vapour deposition of hydrophilic compounds. 
     
     
         31 . A method for preparing an analyte test element according to  claim 26 , wherein the areas of high surface energy of first and second surfaces are physically elevated from the areas of low surface energy by etching or embossing. 
     
     
         32 . A method for preparing an analyte test element according to  claim 29 , wherein said areas of low surface energy are printed on the first and second surface by the means of flexography or lithography. 
     
     
         33 . A method for preparing an analyte test element according to  claim 26 , wherein the base layer ( 2 ) and the cover layer ( 4 ) are formed from one flexible substrate ( 49 ) and folded along a longitudinal centred fold line ( 51 ) to enclose the centre layer ( 3 ) in a manner that the sample distribution system ( 6 ) with the predetermined detection areas ( 6 ′a,  6   a ) of said first surface ( 2   a ) and second surface ( 4   a ) are aligned and registered to be mostly congruent. 
     
     
         34 . An analyte test system for determining the concentration of an analyte in a physiological or aqueous sample fluid comprising
 an analyte test element or analyte test arrangement according to  claim 1 , wherein n predetermined detection areas ( 6 ′ a ) of a first surface ( 2   a ) are coated with a catalytic formulation promoting the detection of an analyte in a physiological or aqueous fluid, and   n predetermined detection areas ( 6   a ) of a second surface ( 4   a ) are coated with n calibration formulations made up of m blank formulations and n−m formulations with different levels of calibration compound, whereby n is an integer number larger than 2, m is an integer number equal or larger than 1, and n>m,   detection means for detecting changes of light absorbance of the physiological or aqueous sample located in 2n predetermined detection areas and obtaining n results from 2n predetermined detection areas, and   processing means for calculating n−m calibration coefficients of a polynomial calibration equation obeying   
       
         
           
             
               
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       and one regression coefficient to validate the quality of the calculated n−m calibration coefficients of the calibration equation. 
     
     
         35 . A method for determining the concentration of at least one analyte in a physiological or aqueous sample, said method comprising
 applying a physiological or aqueous sample to an analyte test element having a first surface ( 2   a ) and a second surface ( 4   a ) in a predetermined distance opposite from each other, said both surfaces are provided with two substantially equivalent patterns forming areas of high and low surface energy which are aligned mostly congruent to create a sample distribution system ( 6 ) with at least two detection areas, wherein the applied physiological or aqueous fluid is constrained to the areas with high surface energy,   detecting the signals produced in the different detection areas, and   relating the signals to determine the amount of the analyte(s) in the physiological or aqueous sample.   
     
     
         36 . An analyte test element for determining the concentration of at least one analyte in a physiological or aqueous sample fluid having a first surface and a second surface in a predetermined distance opposite from each other, wherein one of the first and second surface is provided with a hydrophilic/hydrophobic pattern and the corresponding surface provides a homogeneous pattern of hydrophilic pixels surrounded by a hydrophobic area therefore creating overall a surface with semi hydrophilic and semi hydrophobic character, whereby the hydrophilic and semi hydrophilic areas create a sample distribution system with at least two detection areas.