ZnO nanostructures in enzyme biosensors

Biosensing has developed tremendously since it was demonstrated by Leland C. Clark Jr. in 1962. ZnO nanomaterials are attractive candidates for fabricating biosensors, because of their diverse range of nanostructures, high electron mobility, chemical stability, electrochemical activity, high isoelectric points which promote enzyme adsorption, biocompatibility, and piezoelectric properties. This review covers ZnO nanostructures applied in enzyme biosensors, in the light of electrochemical transduction and field effect transduction. Different assembly processes and immobilization methods have been used to load enzymes into various ZnO nanostructures, providing enzymes with favorable micro-environments and enhancing their sensing performance. We briefly describe recent trends in ZnO syntheses, and the analytical performance of the fabricated biosensors, summarize the advantages of using ZnO nanostructures in biosensors, and conclude with future challenges and prospects.