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

Hydrogen peroxide (H₂O₂) 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 H₂O₂ monitoring, the applied voltage for H₂O₂ electrooxidation possibly gave rise to an abnormal expression and inadequate accuracy, which was still an inescapable concern. Hence, we decorated an interlaced CuO@TiO₂ 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@TiO₂ NWs synergistically exhibited great stretchability and the PEC platform enabled stable photocurrent responses from the reduction of H₂O₂ even during mechanical deformation. Moreover, the admirable biocompatibility and an almost negligible open circuit voltage of +0.18 V for the CuO@TiO₂ 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 H₂O₂ release during HUVECs deformation, in which H₂O₂ 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.