Bioinspired 5-caffeoylquinic acid capped silver nanoparticles using Coffee arabica leaf extract for high-sensitive cysteine detection

Selection of plant extracts as bioactive phytochemical source to synthesize nanoparticles is highly demanding due to the biocompatibility, nontoxicity, and cost-effectiveness over other available physical and chemical methods. Here, for the first time, Coffee arabica leaf extracts (CAE) were used to produce highly stable silver nanoparticles (AgNPs) and the corresponding bio reduction, capping and stabilization mechanism mediated by dominant isomer 5-caffeoylquinic acid (5-CQA) is discussed. UV-Vis, FTIR, mu Raman spectroscopy, TEM, DLS and Zeta potential analyzer measurements were employed to characterize these green synthesized NPs. The affinity of 5-CQA capped CAE-AgNPs to thiol moiety of amino acid is utilized for the selective as well as sensitive detection of L-cysteine (L-Cys) to a low detection limit of 0.1 nM, as obtained from its mu Raman spectra. Hence, the proposed novel, simple, eco-friendly, and economically sustainable method can provide a promising nanoplatform in the field of biosensors compliant with large-scale industrial production of AgNPs without aid of further instrumentation.

Automated summary

Selection of plant extracts as bioactive phytochemical source to synthesize nanoparticles is highly demanding due to their biocompatibility, nontoxicity, and cost-effectiveness. In this study, Coffee arabica leaf extracts (CAE) were used to produce highly stable silver nanoparticles (AgNPs), and the mechanism of bio reduction, capping, and stabilization mediated by 5-caffeoylquinic acid (5-CQA) is discussed. The green synthesized NPs were characterized using various techniques, and the affinity of 5-CQA capped CAE-AgNPs for thiol moiety of amino acid was utilized for sensitive detection of L-cysteine (L-Cys).