Fluorescent sensor based on PtS-PEG nanosheets with peroxidase-like activity for intracellular hydrogen peroxide detection and imaging.

Hydrogen peroxide (HO) is produced in living organisms and is involved in a variety of redox-regulated processes. Therefore, the detection of HO is important for tracing the molecular mechanisms of some biological events. Here, we demonstrated for the first time the peroxidase activity of PtS-PEG NSs under the physiological conditions. PtS NSs were synthesized by mechanical exfoliation followed by functionalization with polyethylene glycol amines (PEG-NH) to improve their biocompatibility and physiological stability. Fluorescence was generated by catalyzing the oxidation of o-phenylenediamine (OPD) by HO in the presence of the PtS NSs. The proposed sensor had a limit of detection (LOD) of 248 nM and a detection range of 0.5-50 μM in the solution state, which was better than or comparable to previous reports in the literature. The developed sensor was further applied for the detection of HO released from cells as well as for imaging studies. The results show that the sensor is promising for future applications in clinical analysis and pathophysiology.