The invention is directed to a measuring sensor for detecting gaseous components which operates in the diffusion limit current region. The measuring sensor includes a support body and has an electrolyte chamber partitioned by a diffusion membrane from the ambient containing the gaseous components. The measuring electrode of the measuring sensor is improved so that a simpler manipulation for covering the electrolyte chamber with a membrane is possible without endangering the mechanical stability of the membrane. During operation, the detection operation is intended to take place completely at that electrode surface which is in direct electrochemical exchange communication with the electrolyte supply. For this purpose, the coating is configured as an adherence joiner to the support body so that it forms an impermeable adherence region in the lateral direction between coating and support body. A process for producing the measuring electrode is characterized in that the coating is adheringly applied to a front face of the support body which forms a closed surface. Thereafter, a membrane layer is applied to the coating and a break through for communicating with the electrolyte chamber is formed in the support body by removing a portion of the support body starting from a rear face thereof lying opposite the front face. The break through is formed by removing the portion of the support body through to the coating. In the completed measuring sensor, this permits electrolyte from the electrolyte chamber to penetrate through the break through to the coating.

An implantable measuring instrument for a body substance for use in controlling an implantable infusion device has a housing with a recess covered by a semi-permeable membrane which permits transfer of molecules of a selected size therethrough. The volume defined by the recess and the membrane is in communication with an expandable chamber in the housing and a channel leading directly or indirectly via an additional membrane to a sensor for the body substances to interest. The channel is also in communication with a pump. There is also provided another recess covered by a pierceable, resealable septum. A conduit leads from the septum to the sensor. For calibrating the instrument, a cannula is introduced through the septum, and all of the fluid in the conduit leading to the sensor is withdrawn by suction. A known calibrating substance is then introduced by the cannula through the septum until the conduit leading to the sensor is filled. Data can then be acquired from the sensor, and if necessary one or more operating parameters of the instrument can be re-set. This procedure can also be used for rinsing and/or reactivating the sensor.

A non-invasive method for measuring blood glucose concentration using glucose present at the mucosal surface of a living being is provided. The method includes the steps of positioning a glucose oxidase membrane on the mucosal surface, providing oxygen for peroxidative oxidation of the glucose present thereat, electrically measuring the amount of hydrogen peroxide product and calibrating that amount to determine blood glucose concentration. Also provided are electrode devices suitable for carrying out the method.

The invention relates to a process for manufacturing a REFET and/or CHEMFET, comprising: (a) covalent bonding of a hydrophilic polymer layer to an isolator layer applied to a semiconductor material; (b) the absorption of water or a watery solution into said hydrophilic polymer layer; and (c) the binding of a hydrophobic polymer layer to the water holding hydrophilic polymer layer. It is advantageous that this water holding hydrophilic polymer layer also contains an electrolyte and/or a buffer. Preferably an ion to be measured with the CHEMFET also forms part of the electrolyte.

The invention is the design of a biological measuring device for the determination of the concentration of biomolecules (e.g. glucose) in an environment which is designed for implantation into an individual or for use in the context of an external apparatus. The device contains a composite membrane that is essentially entirely permeable to oxygen and permeable to larger biomolecules only in discrete hydrophilic regions. The membrane diffusionally limits the access of biomolecules to an enzyme, present in the hydrophilic region that catalyzes the oxidation of the biomolecule to produce hydrogen peroxide. A sensor in communication with the hydrophilic region is used to determine the amount of product produced or the amount of excess oxygen present allowing for the concentration of the biomolecule to be determined.