Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode

GALLAY, PABLO; TOSI, EXEQUIEL; MADRID, ROSSANA ELENA; TIRADO, MÓNICA; COMEDI, DAVID

Nanotechnology

IOP science

Año: 2016 vol. 27

We present a glucose biosensor based on ZnO nanowire self-sustained films grown oncompacted graphite flakes by the vapor transport method. Nanowire/graphite films werefragmented in water, filtered to form a colloidal suspension, subsequently functionalized withglucose oxidase and finally transferred to a metal electrode (Pt). The obtained devices wereevaluated using scanning electron microscopy, energy-dispersive x-ray spectroscopy, cyclicvoltammetry and chronoamperometry. The electrochemical responses of the devices weredetermined in buffer solutions with successive glucose aggregates using a tripolar electrodesystem. The nanostructured biosensors showed excellent analytical performance, with linearresponse to glucose concentrations, high sensitivity of up to ≈17 μA cm−2mM−1 in the0.03?1.52mM glucose concentration range, relatively low Michaelis?Menten constant, excellentreproducibility and a fast response. The detection limits are more than an order of magnitudelower than those achievable in commercial biosensors for glucose control, which is promisingfor the development of glucose monitoring methods that do not require blood extraction frompotentially diabetic patients. The strong detection enhancements provided by the functionalizednanostructures are much larger than the electrode surface-area increase and are discussed interms of the physical and chemical mechanisms involved in the detection and transductionprocesses.