Biosynthesis-mediated Ni-Fe-Cu LDH-to-sulfides transformation enabling sensitive detection of endogenous hydrogen sulfide with dual-readout signals.

Hydrogen sulfide (H2S) is a vital endogenous gas signal molecule undertaking numerous physiological functions such as biological regulation and cytoprotection. Herein, we developed an electrochemical (EC) and photothermal (PT) dual-readout signals method for H2S detection based on a novel biosynthesis-mediated Ni-Fe-Cu LDH-to-sulfides transformation strategy. Interestingly, the Cu2+-based Ni-Fe LDH (Ni-Fe-Cu LDH) can act as the Cu2+ source to react with H2S, resulting in the in-situ generation of CuxS on Ni-Fe-Cu LDH surfaces. Because of the EC signal and intrinsic near-infrared (NIR) PT conversion ability of CuxS under 808 nm laser irradiation, the obtained CuxS@Ni-Fe-Cu LDH is applied to stimulate EC signal and temperature readout. By this means, a dual-readout signal mode is established for H2S detection. Under the optimum conditions, this combination of EC and PT methods displays a wide linear range for H2S to 0.1 μM-90 μM and 50 μM-400 μM, respectively, with a low detection limit of 0.09 μM. In addition, the practicality of Ni-Fe-Cu LDH is verified by determination of endogenous H2S in living cells. This work not only provides a promising application for H2S diagnosis but also exhibits the new characteristic of Ni-Fe-Cu LDH nanomaterials as signal transduction tags.