Abstract: Hydrogels containing catalase co-immobilized with an analyte-sensitive enzyme such as glucose oxidase are disclosed. The hydrogels may be pH-sensitive, and preferably are thin and lightly crosslinked. The catalase is present in concentrations ranging generally from 100 units/ml to about 1000 units/ml. These hydrogels have much faster swelling response times as compared to hydrogels without catalase, and are useful in biosensors and analyte-responsive drug delivery devices. The hydrogels also have an increased useful life, due to protection of the immobilize analyte-sensitive enzyme from degradation by hydrogen peroxide.

Abstract: An implantable biosensor for detecting an analyte in vivo in body fluids comprises an analyte-sensitive hydrogel filament chemically configured to vary its displacement volume according to changes in concentration of an analyte, such as glucose, in a patient's body fluid. A photometric displacement transducer placed inside the biosensor is configured to quantifiably detect changes in the displacement volume of the hydrogel filament, such as by detecting the light intensity on a photoreceptor arranged to receive light of varying intensity depending upon the displacement of the hydrogel filament. A battery powered telemeter operably engaged to the photometric displacement transducer sends a radio data signal representing glucose concentration level to a receiver containing an alarm system. The alarm system can automatically notify a person that the analyte level is outside desired predetermined parameters, and/or to automatically inject an agent to counteract the adverse analyte levels.

Abstract: A biosensor (10) has a hydrogel (30) in a rigid and preferably biocompatible enclosure (20). The hydrogel (30) includes an immobilized analyte binding molecule (ABM) and an immobilized analyte. The immobilized analyte competitively binds with free analyte to the ABM, thus changing the number of crosslinks in the hydrogel (30), which changes hydrogel swelling tendency (and thus the osmotic pressure) in its confined space in proportion to the concentration of free analyte concentration. By measuring the change in hydrogel pressure with a pressure transducer (40), the biosensor (10) is able to accurately measure the concentration of the free analyte molecule without the problem of oxygen limitations and interference encountered by prior art biosensors. A battery (64) powered telemeter (60) operably engaged to the pressure transducer (40) sends a radio data signal to a receiver (66) containing an alarm system operably attached to a computer (62).

Abstract: A biosensor (10) has a hydrogel (30) in a rigid and referably biocompatible enclosure (20). The hydrogel (30) includes an immobilized glucose-binding molecule such as concanavalin A (Con A) and an immobilized hexose saccharide such as a-D-mannopyranoside. The immobilized hexose saccharide competitively binds with free glucose to the glucose-binding molecules, thus changing the number of crosslinks in the hydrogel (30), which changes hydrogel swelling tendency and the pressure of the hydrogel in its confined space in proportion to the concentration of free glucose. By measuring the change in hydrogel pressure with a pressure transducer (40), the biosensor (10) is able to accurately measure the concentration of the tree glucose molecule without the problem of oxygen limitations and interference encountered by prior art biosensors.

Abstract: A biosensor (10) has a pH-sensitive polymeric hydrogel (30) in a rigid and preferably biocompatible enclosure (20). The hydrogel (30) includes an immobilized oxidoreductase enzyme such as glucose oxidase. The oxidoreductase enzyme catalyzes a chemical reaction consuming an organic molecule and producing a byproduct. The hydrogel (30) changes its osmotic pressure in proportion to the concentration of a byproduct. By measuring the change in osmotic pressure with a pressure transducer (40), the biosensor (10) is able to accurately measure the concentration of the organic molecule without the problem of interference encountered by prior art biosensors. A battery (64) powered telemeter (60) operably engaged to the pressure transducer (40) sends a radio data signal to a receiver (66) operably attached to a computer (62).