Three-dimensional WS sub(2) nanosheet networks for H sub(2)O sub(2) produced for cell signaling

Hydrogen peroxide (H sub(2)O sub(2)) is an important molecular messenger for cellular signal transduction. The capability of direct probing of H sub(2)O sub(2) in complex biological systems can offer potential for elucidating its manifold roles in living systems. Here we report the fabrication of three-dimensional (3D) WS sub(2) nanosheet networks with flower-like morphologies on a variety of conducting substrates. The semiconducting WS sub(2) nanosheets with largely exposed edge sites on flexible carbon fibers enable abundant catalytically active sites, excellent charge transfer, and high permeability to chemicals and biomaterials. Thus, the 3D WS sub(2)-based nano-bio-interface exhibits a wide detection range, high sensitivity and rapid response time for H sub(2)O sub(2), and is capable of visualizing endogenous H sub(2)O sub(2) produced in living RAW 264.7 macrophage cells and neurons. First-principles calculations further demonstrate that the enhanced sensitivity of probing H sub(2)O sub(2) is attributed to the efficient and spontaneous H sub(2)O sub(2) adsorption on WS sub(2) nanosheet edge sites. The combined features of 3D WS sub(2) nanosheet networks suggest attractive new opportunities for exploring the physiological roles of reactive oxygen species like H sub(2)O sub(2) in living systems.