Biosensor

A biosensor for measuring the concentration of glucose in a person, the biosensor comprising:

• a rigid, biocompatible enclosure having an open end and a closed end, the open end being covered by a semipermeable membrane;
• a flexible diaphragm being positioned between the semipermeable membrane and the closed end;
• and a polymeric hydrogel enclosed between the semipermeable membrane and the diaphragm, the hydrogel including moieties that cause the hydrogel to change its osmotic pressure in proportion to the pH of the hydrogel;
• an amount of glucose oxidase immobilized in the hydrogel;
• a capacitance pressure transducer operatively engaged to the diaphragm;
• and
• a battery powered telemeter operatively engaged to the transducer.

A method for using a biosensor to measure the concentration of an organic molecule in a solution, the method comprising the steps of:

• a) providing a biosensor comprising:
• a rigid, biocompatible enclosure having an open end and a closed end, the open end being covered by a semipermeable membrane;
• a flexible diaphragm being positioned between the semipermeable membrane and the closed end;
• and a polymeric hydrogel enclosed between the semipermeable membrane and the diaphragm, the hydrogel including moieties that cause the hydrogel to change its osmotic pressure in proportion to the pH of the hydrogel;
• an oxidoreductase enzyme immobilized in the hydrogel
• a means for measuring the osmotic pressure of the hydrogel, the means for measuring being associated with the diaphragm;
• and
• a means for reporting the concentration of the organic molecule based on the measured osmotic pressure of the hydrogel;
• b) providing a solution, the solution containing an amount of the organic molecule;
• c) inserting the biosensor into the solution;
• d) allowing the organic molecule to diffuse into the polymeric hydrogel;
• e) allowing the oxidoreductase enzyme to catalyze a chemical reaction consuming the organic molecule and producing the byproduct;
• f) measuring the osmotic pressure of the hydrogel with the means for measuring;
• g) sending data regarding the osmotic pressure of the hydrogel from the means for measuring to the means for reporting;
• and
• h) reporting the concentration of the organic molecule based upon the osmotic pressure of the hydrogel measured by the means for measuring.