Book Description
Development of simple and painless techniques of monitoring metabolites like glucose with increased frequency would be beneficial to diabetic patients. Implantable sensors for glucose have been under investigation for nearly three decades, Poor stability and sensitivity of these sensors limit their use in closed-loop delivery. In this work we have taken advantage of silicon micro-fabrication technologies to develop implantable redundant microsensor arrays with glucose oxidase molecules immobilized in photopolymerized and microlithographically patterned films. We have used redox polymers that exchange electrons with glucose oxidase and also form macromolecular networks with these enzymes. The enzymes entrapped in these polymer films and containing biocompatible hydrogels show good stability and sensitivity. Key accomplishments include: a)Successively synthesized an osmium based polycationic redox polymer (POs-Ea) a molecule that is responsible for exchanging electrons with glucose oxidase enzyme; b) Used photolithography to fabricate patterned sensor arrays on flexible plastic substrates (mylar and polyimide); c) Successively crosslinked active glucose oxidase enzyme with redox polymer and biocompatible polyethylene glycol diacrylate hydrogel; d)Used amperometry and cyclic voltammetry to confirm activity of the enzyme and contribution of each sensor array element; e) The enzyme exchanged electrons with redox polymer both entrapped in a hydrogel network.