MoS2/Pt nanocomposite-functionalized microneedle for real-time monitoring of hydrogen peroxide release from living cells

Abstract

This work describes the adaptive use of a conventional stainless steel acupuncture needle as the electrode substrate for construction of a molybdenum disulfide (MoS₂) and platinum nanoparticles (PtNPs) layer-modified microneedle sensor for real-time monitoring of hydrogen peroxide (H₂O₂) release from living cells. To construct the nanocomposite-functionalized microneedle, the needle surface was first coated with a gold film by ion sputtering to enhance the conductivity. Subsequently, an electrochemical deposition method was successfully employed to deposit MoS₂ nanosheet and Pt nanoparticles on the needle tip as the sensing interface. Electrochemical study demonstrated that the MoS₂/PtNPs nanocomposite-modified needle exhibited excellent catalytic performance and low over-potential toward the reduction of H₂O₂. Not only did the microneedle achieve a wide linear range from 1 to 100 μmol L⁻¹ with a limit of detection down to 0.686 μmol L⁻¹, but it also realized the highly specific detection of H₂O₂. Owing to these remarkable analytical advantages, the prepared microneedle was applied to determine H₂O₂ release from living cells with satisfactory results. The MoS₂/PtNPs nanocomposite-functionalized microneedle sensor is simple and affordable, and can serve as a promising electrochemical nonenzymatic sensing platform. Moreover, this superfine needle sensor shows great potential for real-time monitoring of reactive oxygen species in vivo with minimal damage.