Multifunctional biocompatible membrane and its application to fabricate a miniaturized glucose sensor with potential for use in vivo.

A multifunctional membrane with biocompatibility, diffusion-limiting effect, and the ability to curtail the responses of an H(2)O(2) electrode to ascorbate and urate was prepared. It was composed of MB, AB, and CTA, where MB is the copolymer of 2-methacryloyloxyethyl phosphorylcholine (MPC) and n-butylmethacrylate (BMA), AB is the copolymer of acrylamide-2-methylpropane sulfonic acid (AMPS) and BMA, CTA is cellulose triacetate. Investigation of the biocompatibility of this membrane showed that, compared with CTA, relatively few platelets bound to it. The membrane was coated onto the working electrode of a needle-type glucose sensor on which immobilized glucose oxidase membrane has been coated. The sensor did not respond to ascorbate and urate at their concentration normally encountered in blood. Its response was not inhibited by metal ions in blood at usual concentration. The sensor exhibited superior thermostability in addition to a rapid response (<90 seconds in batch operation), good reproducibility (RE<5%), good stability (more than 36 hours continuously in heparinized whole blood), and a wide dynamic range (5-650 mg/dl glucose). The sensor was used to determine glucose in serum. The data obtained from the sensor showed good agreement with that from a clinical autoanalyzer (R=0.973).