Flexible and Stretchable Photoelectrochemical Sensing toward True-to-Life Monitoring of Hydrogen Peroxide Regulation in Endothelial Mechanotransduction.

Hydrogen peroxide (HO) levels play a vital role in redox regulation and maintaining the physiological balance of living cells, especially in cell mechanotransduction. Despite the achievements on strain-induced cellular HO monitoring, the applied voltage for HO electrooxidation possibly gave rise to an abnormal expression and inadequate accuracy, which was still an inescapable concern. Hence, we decorated an interlaced CuO@TiO nanowires (NWs) semiconductor meshwork onto a polydimethylsiloxane film-supported gold nanotubes substrate (Au NTs/PDMS) to construct a flexible photoelectrochemical (PEC) sensing platform. Under white light irradiation, CuO@TiO NWs synergistically exhibited great stretchability and the PEC platform enabled stable photocurrent responses from the reduction of HO even during mechanical deformation. Moreover, the admirable biocompatibility and an almost negligible open circuit voltage of +0.18 V for the CuO@TiO NWs/Au NTs/PDMS sensor guaranteed human umbilical vein endothelial cells (HUVECs) adhesion tightly thereon even under continuous illumination for 30 min. Finally, the as-proposed stretchable PEC sensor achieved sensitive and true-to-life monitoring of transient HO release during HUVECs deformation, in which HO release was positively correlated to mechanical strains. This investigation opens a new shade path on in situ cellular sensing and meanwhile greatly expands the application mode of the PEC approach.