Green synthesis, characterization of procyanidin-mediated gold nanoparticles and its application in fluorescence detection of prazosin

Grape seed procyanidin extract was used to green synthesize AuNPs (OPC-AuNPs), in which procyanidin (OPC) accounted for 95% of total content. To improve the dispersion and uniformity of particle size, various conditions were optimized. The final OPC-AuNPs showed excellent stability and were characterized by a series of techniques. Owing to the good quenching properties of OPC-AuNPs, the fluorescence system of OPC-AuNPs and Rhodamine B (RB) mixture was established for prazosin testing. OPC-AuNPs could effectively quench fluorescence based on fluorescence resonance energy transfer (FRET). When prazosin and the testing system of OPC-AuNPs and RB mixture coexisted in the solution, prazosin would replace RB and competitively bond on the surface of OPC-AuNPs, thus RB was dissociated from OPC-AuNPs, resulting in the rapid recovery of fluorescence. This article provided a green, simple one-pot synthesis method for OPC-AuNPs and established a fast, sensitive, visible fluorescence system for prazosin detection which was successfully applied in real sample detection.