Dual-mode biosensing platform for sensitive and portable detection of hydrogen sulfide based on cuprous...

Hydrogen sulfide (H₂S) can not only be regarded as a critical gas signal transduction substance, but also its excess levels can lead to a range of diseases. Currently, the accurate analysis combined with electrochemical (EC) or photothermal (PT) technology for H₂S in a complex biological system remains a significant challenge. Herein, an endogenous H₂S-triggered heterojunction cuprous oxide/gold/copper metal organic framework (Cu₂O/Au/HKUST-1) nanoprobe is designed for dual-mode EC- second near-infrared (NIR-II)/PT analysis in tumor cells with high sensitivity and simplicity. Dual-mode EC quantification - PT is achieved through "off-on" mode of EC and PT signals based on electronic transfer and biosynthesis via an in situ sulfuration reaction. Under the optimum conditions, the EC quantification mode for trace H₂S exhibits a wide linear range and an excellent limit of detection of 0.1 μM. More importantly, the dual-mode can display the selective detection of trace H₂S in living tumor cells because of the specific interaction between copper ion and H₂S. These results provide a new EC-PT promising biosensing platform for noninvasive intelligent detection of H₂S in living tumor cells.