Abstract: A biosensor for determining the concentration of an analyte in a biological sample. The biosensor comprises a support, a reference electrode or a counter electrode or both disposed on the support, a working electrode disposed on the support, the working electrode spaced apart from the other electrode or electrodes on the support, a covering layer defining a sample chamber over the electrodes, an aperture in the covering layer for receiving a sample, and at least one layer of mesh in the sample chamber between the covering layer and the electrodes. The at least one layer of mesh has coated thereon a silicone surfactant. Certain silicone surfactants are as effective as fluorinated surfactants with respect to performance of biosensors. These surfactants, when coated onto the mesh layer of the biosensor, are effective in facilitating the transport of aqueous test samples, such as blood, in the sample chamber.

Abstract: The present invention is based on the discovery of NAD+ and NADP+ mediator compounds that do not bind irreversibly to thiol groups in the active sites of intracellular dehydrogenase enzymes. Such mediator compounds avoid a common mode of enzyme inhibition. The mediators can therefore increase the stability and reliability of the electrical response in amperometric electrodes constructed from NAD- or NADP-dependent enzymes.

Abstract: The present invention provides reagent compositions, and analyte measuring devices and methods that utilize the reagent compositions.

Abstract: Half-sandwich complexes of transition metals having a single .pi.-ligand with delocalised .pi. bonding are of use in mediating electron transfer between an electrode and a redox protein, for example an oxidoreductase enzyme such as in an amperometric enzyme sensor. Suitable compounds include complexes of the general formula:(.pi.-ligand)M(not-.pi.-ligand).sub.nwherein the complex is charged or neutral, .pi.-ligand represents the single .pi.-bonded ligand, M represents the transition metal atom, n is the number of ligands which are not .pi.-ligands, and the n not-.pi.-ligands are the same or different, are univalent or multivalent, and serve to satisfy the valency of the transitional metal M.