Flexible and\nStretchable Photoelectrochemical Sensing\ntoward True-to-Life Monitoring of Hydrogen Peroxide Regulation in\nEndothelial Mechanotransduction

Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) levels\nplay a vital\nrole in redox regulation and maintaining the physiological balance\nof living cells, especially in cell mechanotransduction. Despite the\nachievements on strain-induced cellular H<sub>2</sub>O<sub>2</sub> monitoring, the applied voltage for H<sub>2</sub>O<sub>2</sub> electrooxidation\npossibly gave rise to an abnormal expression and inadequate accuracy,\nwhich was still an inescapable concern. Hence, we decorated an interlaced\nCuO@TiO<sub>2</sub> nanowires (NWs) semiconductor meshwork onto a\npolydimethylsiloxane film-supported gold nanotubes substrate (Au NTs/PDMS)\nto construct a flexible photoelectrochemical (PEC) sensing platform.\nUnder white light irradiation, CuO@TiO<sub>2</sub> NWs synergistically\nexhibited great stretchability and the PEC platform enabled stable\nphotocurrent responses from the reduction of H<sub>2</sub>O<sub>2</sub> even during mechanical deformation. Moreover, the admirable biocompatibility\nand an almost negligible open circuit voltage of +0.18 V for the CuO@TiO<sub>2</sub> NWs/Au NTs/PDMS sensor guaranteed human umbilical vein endothelial\ncells (HUVECs) adhesion tightly thereon even under continuous illumination\nfor 30 min. Finally, the as-proposed stretchable PEC sensor achieved\nsensitive and true-to-life monitoring of transient H<sub>2</sub>O<sub>2</sub> release during HUVECs deformation, in which H<sub>2</sub>O<sub>2</sub> release was positively correlated to mechanical strains.\nThis investigation opens a new shade path on in situ cellular sensing\nand meanwhile greatly expands the application mode of the PEC approach.