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

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 Forster 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.