Enhancing the performance of photoelectrochemical glucose sensor via the electron cloud bridge of Au in SrTiO3/PDA electrodes

Abstract

Developing photoelectrochemical biosensors via efficient photogenerated-charge separation remains a challenging task in biomolecular detection. In this study, we utilised a simple approach for constructing an efficient photoactive organic–inorganic heterojunction interface composed of SrTiO₃ with high photocatalytic activity and polydopamine (PDA) with high biocompatibility and electrical conductivity. Gold nanoparticles with dense electron cloud properties were introduced as a bridge between SrTiO₃ and PDA (SrTiO₃/Au/PDA). The Au bridge allowed the PDA to uniformly and tightly attach on the surface of SrTiO₃ electrodes and also provided a separate transmission channel for electrons from PDA to SrTiO₃. The rapidly transmitted electrons were captured by a signal-acquisition system, thereby improving the photocurrent signal output. The 3D hollowed out SrTiO₃/Au/PDA biosensor manufactured herein was used for glucose detection. The biosensor achieved ultrahigh sensitivities reaching 23.7 μA mM⁻¹ cm⁻², an extended linear range (1–20 mM), and a low detection limit (0.012 mM). The excellent results of glucose analysis in serum samples further confirmed the feasibility of the biosensor in clinical applications. In summary, the proposed strategy allowed for the use of an electronic cloud bridge in the construction of glucose biosensors with satisfactory performances, which is promising for the future fabrication of high-performance biosensors.