Three-dimensional WS2 nanosheet networks for H2O2 produced for cell signaling

Abstract

Hydrogen peroxide (H₂O₂) is an important molecular messenger for cellular signal transduction. The capability of direct probing of H₂O₂ in complex biological systems can offer potential for elucidating its manifold roles in living systems. Here we report the fabrication of three-dimensional (3D) WS₂ nanosheet networks with flower-like morphologies on a variety of conducting substrates. The semiconducting WS₂ 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 WS₂-based nano-bio-interface exhibits a wide detection range, high sensitivity and rapid response time for H₂O₂, and is capable of visualizing endogenous H₂O₂ produced in living RAW 264.7 macrophage cells and neurons. First-principles calculations further demonstrate that the enhanced sensitivity of probing H₂O₂ is attributed to the efficient and spontaneous H₂O₂ adsorption on WS₂ nanosheet edge sites. The combined features of 3D WS₂ nanosheet networks suggest attractive new opportunities for exploring the physiological roles of reactive oxygen species like H₂O₂ in living systems.