Patent ID: 6046008
Filing Date: 2000-04-04
Classification: G01N,Y10S

Abstract:
A test apparatus for determining the presence of an analyte in a solution or an aqueous sample, said apparatus comprising:(a) a buffered reagent comprising a first and second ion species;(b) a biological recognition molecule which specifically binds to said analyte and an analog thereof;(c) an absorbent matrix, said matrix interfaced with(d) a lipophilic membrane comprising:(i) a lipophilized chromoionophore which selectively binds to and transports said first ion species into said membrane, said chromoionophore changing from a first color to a second color upon selective binding to said first ion species,(ii) an affinophore which specifically binds to said biological recognition molecule and comprising said analyte or said analog thereof conjugated to an ionophore which selectively binds to and transports said second ion species into said membrane, and(iii) a lipophilic counter-ion present in an amount sufficient to maintain within said membrane a condition of ion exchange between said first ion species and said second ion species,wherein said specific binding of the biological recognition molecule to said affinophore alters the selective binding and transport of the second ion species into said membrane, thereby increasing the selective binding and transport of the first ion species into said membrane to maintain the balance of charge within said membrane such that the presence or amount of said second color in said membrane is inversely proportional to the presence or amount of said analyte in the sample.