Vapor–liquid–solid grown silicananowire based electrochemical glucose biosensor

Abstract

Vapor–liquid–solid (VLS) grown silica nanowires (SiO₂NWs) have been deposited electrophoretically on a gold electrode and utilized for covalent immobilization of glucose oxidase (GOx). Covalent binding has been achieved via3-aminopropyltriethoxysilane (APTES) modification and N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide chemistry. Scanning electron microscopy, transmission electron microscopy and cyclic voltammetry techniques have been used to characterize SiO₂NW and GOx/APTES/SiO₂NW/Au bioelectrode. Electrochemical studies reveal that SiO₂NW increases the effective electro-active surface area thus resulting in higher loading of enzyme. Response characteristics show linearity in the range of interest 25–300 mg dl⁻¹, with a detection limit of 11 mg dl⁻¹, sensitivity: 0.463 µA (mg dl⁻¹)⁻¹ and regression coefficient of 0.992.