Lead halide perovskites with aggregation-induced emission feature coupled with gold nanoparticles for fluorescence detection of heparin.

Herein, a new kind of lead halide perovskites (LHPs, (C12H25NH3)2PbI4) with aggregation-induced emission (AIE) feature is developed as a fluorescent probe for heparin (Hep). The LHPs exhibit a high emission when they aggregate in water. Interestingly, a few pM dispersed gold nanoparticles (AuNPs) can quench the emission of LHPs, but the aggregated AuNPs are invalid. When protamine (Pro) is mixed with AuNPs at first, the negative charged AuNPs aggregate through electrostatic interaction, producing the AIE recovery. Nevertheless, Hep disturbs the interaction between AuNPs and Pro due to its strong electrostatic interaction with Pro. Therefore, the dispersed AuNPs quench the fluorescence of LHPs again. The response linear range of Hep is obtained from 0.8 to 4.2 ng/mL, and the detection limit is 0.29 ng/mL. Compared with other probes for determination of Hep with AuNPs, this strategy exhibits a better sensitivity due to a small amount of AuNPs used. Finally, it is also successfully applied to detect Hep in human serum samples with satisfactory recoveries.