A novel fluorescent nanoprobe based on platinum nanoclusters with the characteristic of aggregation-induced emission for the detection of Cu2+ and D-penicillamine.

In this work, platinum nanocluster (Pt NCs) with AIE property using L-glutathione (L-GSH) as the protecting ligand are reported. The solid-state photoluminescence quantum yields of obtained Pt NCs powder is as high as 8.0 %. The as-prepared Pt NCs exhibited solvent-induced emission. Specifically, they exhibited gradually enhanced red fluorescent emission as the volume ratio of ethanol to H2O increases. Additionally, the obtained Pt NCs presented excellent stability and resistance to photobleaching in the mixed solvent of ethanol and H2O. Based on the fluorescent quenching effect of Pt NCs induced by Cu2+ and the strong coordination interaction between Cu2+ and thiol group of D-penicillamine (D-Pen), a novel "off-on" fluorescent nanoprobe was proposed for quantifying the labelling amount percentage of commercially available D-penicillamine tablets. Experimental results demonstrated the fluorescent quenching from our proposed Pt NCs-based nanoprobe was linearly correlated with Cu2+ concentration within the range from 1 to 28 μM, with a limit of detect (LOD) of 0.13 μM. Besides, upon addition of D-Pen into a mixed system containing Pt NCs and Cu2+, fluorescent intensities of Pt NCs were recovered and exhibited concentration-dependent responses within a concentration of D-Pen from 1 to 120 μM, with an LOD of 0.058 μM. Spiked sample experiment validated that our proposed nanoprobe possessed an outstanding accuracy, which expands the potential application of metal nanoclusters exhibiting AIE effects in pharmaceutical analysis.