Biomineralization-Driven Ion Gate in TiO₂ Nanochannel Arrays for Cell H₂S Sensing

The level of hydrogen sulfide in the brain and vasculature has long been associated with human health and diseases. Hence, simple and robust analytical tools allowing determination of hydrogen sulfide levels are highly desirable. In this work, a biomineralization-driven ion gate in TiO₂ nanochannel arrays for H₂S sensing was designed and developed. The formed CuS precipitation decreased the transmembrane current in the presence of bovine serum albumin used as biological mineralizer. Label-free assay for sensing of intracellular S^2– was achieved based on changes in ionic current with a detection limit of 56 MCF-7 cells. More importantly, the proposed sensing strategy was promising for reusable application through dissolution of CuS in an acidic media (pH = 1).