Probing nanometal surface energy transfer between nanocopper and MoS2 for glutathione sensing

Abstract

Abstract Cu nanoparticles and 2D-MoS2 nanosheets have been synthesised and the morphology of the prepared samples has been characterised using high-resolution transmission electron microscopy and field emission scanning electron microscopy. Steady-state fluorescence studies exhibit quenching of fluorescence intensity upon the addition of quencher in varying amounts. Time-resolved fluorescence studies show a reduction of fluorescence lifetime in the presence of quencher. A thorough investigation of energy transfer between MoS2 and copper nanoparticles has been accomplished using steady-state and time-resolved fluorescence studies. The results are more consistent with the nanometal surface energy transfer (NSET) theory, which follows a 1/d 4 distance dependence than the Förster resonance energy transfer theory exhibiting 1/d 6 distance dependence. For the MoS2–Cu pair, the NSET efficiency, the proximal distance between donor–acceptor pairs and the rate of energy transfer has been explored. Energy transfer-based fluorescent biosensors have been regarded as potential candidates in biosensing applications. Glutathione, an endogenous tripeptide compound, plays a vital role as an antioxidant in the human body. Irregular glutathione levels have been linked to several adverse illnesses. Henceforth, detection of glutathione levels is indispensable. The Cu–MoS2 pair was used for glutathione sensing in nanomolar concentration (nM), which demonstrated a turn-off sensing behaviour.