Amperometric Glucose Sensing at Nanomolar Level Using MOF-Encapsulated TiO₂ Platform

Abstract

A new synthetic approach is established where both TiO₂ nanoparticles and glucose oxidase (GO <i>_x</i> ) are together encapsulated into the cavity of ZIF-8 metal-organic framework (MOF) to fabricate a mediator-free glucose sensor in aqueous media. ZIF-8 possesses high stability both physically and chemically. Moreover, its large surface area and tunable cavity size are supportive to encapsulate both nanoparticles (TiO₂) and enzymes (GO <i>_x</i> ). The as-synthesized nanocomposite is methodically characterized by various advanced analytical techniques, which suggests that TiO₂ is uniformly distributed within the cavity of ZIF-8 MOF. High surface area and double-layer capacitance of nanostructured TiO₂ jointly enhance the catalytic biosensor activity. The as-synthesized nanocomposite exhibits commendable stability and is able to detect low-level concentration (80 nM) of glucose in aqueous media by utilizing very low concentration of GO <i>_x</i> (62 μg in 1 mL).