A field effect glucose sensor with a nanostructured amorphous In-Ga-Zn-O network

Amorphous indium gallium zinc oxide (IGZO) field effect transistors (FETs) are a promising technology for a wide range of electronic applications. Herein, we fabricated and characterized FETs with a nano-structured IGZO network as a sensing transducer. The IGZO was patterned using colloidal lithography and electrohydrodynamic printing, where an 8 mu m wide nanostructured close-packed hexagonal IGZO network was obtained. Electrical characterization of the nanostructured IGZO network FET demonstrated a drain-source current on-off ratio of 6.1 x 10(3) and effective electron mobilities of 3.6 cm(2) V-1 s(-1). The nanostructured IGZO network was functionalized by aminosilane groups with cross-linked glucose oxidase. The devices demonstrated a decrease in drain-source conductance and a more positive V-ON with increasing glucose concentration. These changes are ascribed to the acceptor-like surface states associated with positively charged aminosilane groups attached to the nanostructured IGZO surface. Continuous monitoring of the drain-source current indicates a stepwise and fully reversible response to glucose concentrations with a short response time. The specific catalytic reaction between the GOx enzyme and glucose eliminates interference from acetaminophen/ ascorbic acid. We demonstrate that nanostructured IGZO FETs have improved sensitivity compared to non-nanostructured IGZO for sensing glucose and can be potentially extended to other biosensor technologies.