Towards self-driven and enzyme-free sweat glucose photoelectrochemical sensing via decorating CuO nanoparticles on TiO2 hierarchical nanotubes

It is of great importance to develop a non-invasive and portable glucose sensor to address challenges and obstacles brought by invasive glucose sensors, such as negative physical and psychological impacts to patients during the fingertip blood collection, limited environment of use for enzyme-based electrodes, and cumbersome active-driven integrated devices. Photoelectrochemical (PEC) sensors have great potential in this regard. In this work, self-driven and enzyme-free sweat glucose PEC sensing is realized by constructing TiO2 hierarchical nanotubes modified by CuO nanoparticles (CuO@TiO2 HNT). A sensitivity of 138.9 & mu;A mM-1 cm-2 in the low concentration range (< 200 & mu;M) and a detection limit of 0.7 & mu;M (Signal/Noise=3) are achieved by the asprepared CuO@TiO2 HNT photoelectrode at relatively zero bias. The testing results for sweat glucose detection before and after meal consumption are consistent with those from commercial glucometers. The CuO@TiO2 HNT photoelectrode works well at absolutely zero bias and in a wide temperature range (e.g., 0-60 C). The extraordinary sensing performance can be mainly attributed to the following two factors: (1) the TiO2 hierarchical nanotubes have an excellent light-capturing property and large specific surface area, and (2) the CuO nanoparticles substantially facilitate surface-carrier transfer for the glucose oxidation reaction. This work provides an enzyme-free sensing photoelectrode for self-driven sweat glucose detection and an alternative route to portable and noninvasive sensing of glucose.

Automated summary

Developing a non-invasive and portable glucose sensor is crucial to address the limitations of invasive glucose sensors. The authors successfully designed a self-driven and enzyme-free sweat glucose sensor using TiO2 hierarchical nanotubes modified by CuO nanoparticles. This photoelectrode showed high sensitivity and low detection limit, and the testing results were consistent with commercial glucometers. The research provides a promising alternative for non-invasive and portable glucose sensing.