Nonenzymatic glucose detection realized by Au and CuO nanoparticle co-modified TiO₂ hierarchical nanotubes integrated with a microfluidic cell

Traditional enzyme-based blood glucose sensors demand stringent environmental conditions, while the current nonenzymatic blood glucose sensors exhibit low sensitivity and a limited detection range, hindering the accurate and swift analysis of minute liquid samples. In this study, the TiO ₂ hierarchical nanotubes (HNTs) were modified with Au and CuO nanoparticles (NPs) in sequence, and the as-prepared CuO-Au@TiO ₂ HNTs was constructed to a sensing photoelectrode and integrated into a self-designed microfluidic photoelectrochemical cell. Accurate monitoring of glucose concentrations in artificial blood, sweat, and saliva was achieved by merely using microliter analyte, along with a satisfactory selectivity and repeatability. Notably, the fitted sensitivity in the concentration range of 1–10 mM was over 29-fold higher than the traditional cell (i.e., non-microfluidic configuration) with the same sensing photoelectrode under one-sun illumination, and a detection limit was as low as 4.1 μM (Signal/Noise = 3). The excellent sensing performances are ascribed to the synergistic effect of the substantial enhancement in optical absorption and carrier transfer and the dynamic flow of glucose confined in micro-channel. This study demonstrates an enzyme-free sensing photoelectrode integrated with a microfluidic cell for high-performance glucose detection, and presents an alternative avenue towards noninvasive and portable diabetes diagnosis.