Constructing a TiO₂/PDA core/shell nanorod array electrode as a highly sensitive and stable photoelectrochemical glucose biosensor

Abstract

Developing stable PEC glucose biosensors with high sensitivity and low detection limit is highly desirable in the biosensor field. Herein, a highly stable and sensitive enzymatic glucose photoelectrochemical biosensor is rationally designed and fabricated by constructing TiO₂/PDA core/shell nanorod arrays. The TiO₂ nanorod as the core has the advantages of increasing charge transportation towards interfaces and enhancing the absorption of incident sunlight due to its single-crystal nature and one dimensional array structure. The PDA shell not only induces a rapid charge transfer across the interfaces but also stabilizes the biosensor performance by avoiding the decomposition of enzymes induced by the strong oxidizing holes from the TiO₂ core. A remarkable performance with an ultrahigh sensitivity of 57.72 μA mM^-1 cm^-2, a linear range of 0.2-1.0 mM, a glucose detection limit of 0.0285 mM (S/N = 3) and a high sensitivity of 8.75 μA mM^-1 cm^-2 in a dynamic range of 1.0-6.0 mM were obtained for the glucose detection. This study might provide a strategy for constructing inorganic/organic core/shell structures with a satisfactory PEC performance.