Trimetallic Hybrid Nanoflower-Decorated MoS2 Nanosheet Sensor for Direct in Situ Monitoring of H2O2 Secreted from Live Cancer Cells

In situ monitoring of hydrogen peroxide (H₂O₂) secreted from live cells plays a critical role in elucidating many cellular signaling pathways, and it is a significant challenge to selectively detect these low levels of endogenous H₂O₂. To address this challenge, we report the establishment of a trimetallic hybrid nanoflower-decorated MoS₂ nanosheet-modified sensor for in situ monitoring of H₂O₂ secreted from live MCF-7 cancer cells. The Au-Pd-Pt nanoflower-dispersed MoS₂ nanosheets are synthesized by a simple wet-chemistry method, and the resulting nanosheet composites exhibit significantly enhanced catalytic activity toward electrochemical reduction of H₂O₂, due to the synergistic effect of the highly dispersed trimetallic hybrid nanoflowers and the MoS₂ nanosheets, thereby resulting in ultrasensitive detection of H₂O₂ with a subnanomolar level detection limit in vitro. Also the immobilization of the laminin glycoproteins on the surface of the nanocomposites increases its biocompatibility for cell adhesion and growth, which enables in situ electrochemical monitoring of H₂O₂ directly secreted from live cells for potential application of such sensor in cellular biology, clinical diagnosis, and pathophysiology.