Abstract: The present invention provides electrochemical biosensors for measuring low concentrations of analytes in biological fluid samples. The biosensors comprise one or more working electrodes, a reference electrode, a counter electrode, and a bio-cocktail. The bio-cocktail comprises one or more enzymes and one or more redox mediators in a buffered solution. The present invention also provides methods of measuring low concentrations of analytes in biological fluid samples using the electrochemical biosensors of the invention.

Abstract: An enzymatic electrode, having a homogeneous composition throughout, consists essentially of a uniform intimate admixture of a conducting powder with at least one immobilized enzyme, or with an immobilized enzyme and a mediator agent or a co-enzyme, in a matrix. The electrode is one which has a surface available for direct contact with a substrate without a permeable or semi-permeable intermediate membrane or membranes. The enzymatic electrode is prepared, e.g., by intimately admixing (a) a homogeneous paste or matrix (resulting from an intimate admixture of a conducting powder with a binder), (b) at least one enzyme and (c) an enzyme crosslinking solution, and then incorporating therein a mediator agent and/or a co-enzyme.