Low-potential detection of glucose with a biosensor based on the immobilization of glucose oxidase on polymer/manganese oxide layered nanocomposite

A nanocomposite with poly(diallyldimethylammonium), PDDA, intercalated between manganese oxide layers is constructed on a graphite electrode surface through one-step electrodeposition and used to adsorb glucose oxidase (GOD). The immobilized GOD displays a pair of stable and quasireversible redox peaks with a formal potential of -468 mV in pH 7.0 buffer solutions and exhibits excellent electrocatalysis to the reduction of oxygen. In the presence of dissolved oxygen, the reduction peak current decreased gradually with the addition of glucose, indicating that the immobilized GOD kept its bioactivity. Thus a reagentless biosensor for glucose at a low detection potential was established. The linear concentration range is from 0.02 to 2.78 mM with a detection limit of 9.8 mu M. The proposed glucose biosensor was insensitive to common interferences such as ascorbic and uric acids etc.