Abstract: A method for in vivo determination of the concentration in a body fluid of metabolically significant substance comprises storing of a needle with a sensor in a liquid-filled ampoule, brief insertion of the needle into a patient, recording of the output signal from the sensor, withdrawal of the needle, and calculation of the concentration looked for on the basis of the recorded signals. The method is preformed using an apparatus comprising a needle (5) with a sensor (6), an ampoule (1) containing a solution (2) and closed by two membranes (3, 4). The needle (5) is stored with its sensor (6) in the solution. The apparatus further comprises a mechanical unit for driving the needle (5) to protrude from the ampoule for a set moment, and an electronic unit storing the output signal from the sensor (6) and performing calculations on the basis of the stored signal values.

Abstract: The present invention relates generally to the immobilization or incorporation of polypeptides, especially enzymes or other bioactive polypeptides into polymeric matrixes, especially polyurethane, membranes produced by said polymers, and the utilization of such membranes in biosensors. A preferred type of biosensor is the needle sensor designed for in vivo monitoring of glucose which comprises a core platinum anode (2) coated with an insulating lacquer (3), the anode (2) is situated inside a stainless steel reference cathode (4) which is insulated from the anode (2) by a layer of epoxy resin (5) At one end, of the tip, the electrode (1) has a detection surface (6) which is in an acute angle to the general direction of the electrode (1). At the other end, the base, the electrode (2) is provided with terminals (7) and (8) for the anode (2) and cathode (4), respectively.