Reproducible fabrication of miniaturized glucose sensors: preparation of sensing membranes for continuous monitoring

The immobilization process of glucose oxidase(GOx) in the poly(1,3-diaminobenzene) (poly(1,3-DAB)) network was closely investigated in situ using an electrochemical quartz crystal microbalance(EQCM). GOx captured in approximately 50 nm thick poly-1,3-DAB layer causes a 514 Hz frequency increase, corresponding to 541 ng, and distributes mostly in the outer part of the polymer film. The presence Of poly-L-lysine and glutaraldehyde during electropolymerization of poly(1,3-DAB) improves sensitivity by raising the amount of GOx immobilized. Adding a protective membrane on to the enzyme layer from poly(tetrafluroethylene) (PTFE) dispersed in aqueous media lets the entire fabrication procedure finish perfectly without nonaqueous solvent. The finalized needle-type glucose sensors show competent functions in sensitiviy, stability, biocompatibility, lifetime, interference and reproducibility. (C) 2001 Elsevier Science B.V. All rights reserved.