Abstract: Novel polarographic (voltametric) methods for measuring in vivo or in vitro analytes in an animal tissue and oxygen in the sensor enzymatic reaction layer with an electroenzymatic sensor are disclosed. The new and vastly improved methods are directed to generating from the electroenzymatic sensor at a suitable voltage an anodic current derived from an anodically active product generated by enzymatic activity on an analyte for measuring the analyte and a cathodic current derived from reducing the oxygen in the sensor enzymatic reaction layer for measuring the oxygen. Additionally, the method contemplates switching the voltage between anodic and cathodic potentials to generate anodic and cathodic currents or applying the voltage at a fixed rate. Advantageously, the methods of this invention may be utilized with implanted sensors in an animal including a human. The sensors may be implanted in blood or non-blood sites.

Abstract: The present invention relates to a novel implantable biosensor and method for sensing products, such as hydrogen peroxide, generated from an enzymatic reaction between an analyte, like glucose, and an enzyme in the presence of oxygen. The novel implantable biosensor is uniquely equipped with an enclosed chamber for containing oxygen and can be adapted for extracting oxygen from animal tissue adjacent the container. The reservoir of oxygen contained in the enclosed chamber is supplied to the enzymatic reaction from the side of the membrane opposite the enzyme. The enclosed chamber is uniquely designed to be impermeable to substances, like liquid and cells, that possibly can interfere with the supply of the oxygen permeating through the membrane to the enzymatic reaction. Also, the implantable biosensor is designed to optically or electrically sense products generated from the enzymatic reaction which serve as a function of the analyte.