Electrochemical glucose biosensor by electrostatic binding of PQQ-glucose dehydrogenase onto self-assembled monolayers on gold

Efficient binding of enzymes onto the electrode surface has been prerequisite for the construction of sensitive biosensors and biochips. Here, a simple and robust construction of electrochemical glucose biosensor based on pyrroloquinoline quinone-glucose dehydrogenase was demonstrated. The glucose biosensor was fabricated by binding the enzyme onto the anionic self-assembled monolayers on gold electrode via electrostatic interactions. The resulting glucose biosensor gave rise to twofold higher detection sensitivity than that by covalent conjugation under the same condition. Surface plasmon resonance and atomic force microscopy analyses revealed that electrostatic binding of the enzyme leads to much higher surface density of the enzyme. This approach will find wide applications to the development of robust enzyme-based biosensors and biochips.