New Titanium Dioxide-Based Heterojunction Nanohybrid for Highly Selective Photoelectrochemical–Electrochemical Dual-Mode Sensors

A new titanium dioxide (TiO2)-based heterojunction nanohybrid (HJNH) composed of TiO2, graphene (G), poly[3-aminophenylboronic acid] (PAPBA), and gold nanoparticles (Au NPs) was synthesized and designated as TiO2(G) NW@PAPBA–Au HJNH. The TiO2(G) NW@PAPBA–Au HJNH possesses dual-mode signal photoelectrochemical (PEC) and electrochemical transduction capabilities to sense glucose and glycated hemoglobin (HbA1c) independently. The synthesis of the HJNH material involved two sequential stages: (i) simple electrospinning synthesis of G-embedded TiO2 nanowires [TiO2(G) NWs] and (ii) one-step synthesis of Au NP-dispersed PAPBA nanocomposite (NC) in the presence of TiO2(G) NWs. The as-synthesized TiO2(G) NW@PAPBA–Au HJNH was characterized by field emission scanning electron microscopy, field emission transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared, thermogravimetric analysis, and UV–visible diffuse reflectance spectroscopy. A PEC platform was develo...