Quercetin-Functionalized Silver Nanoparticles as Selective Colorimetric Sensor of Hg2+ in Water and Studies on Interactions between the Nanoparticles and Bovine Serum Albumin

Abstract

Quercetin functionalized silver nanoparticles (QC-AgNPs) were synthesized using quercetin as reducing and stabilizing agent. UV-Vis and FTIR spectroscopy along with transmission electron microscopy (TEM) were used to confirm the fabrication of functional nanoparticles. QC-AgNPs demonstrated remarkable sensitivity and selectivity in the detection of Hg2+ in water. The probe also exhibited strong anti-interference performance against other metal ions. The detection limit (LOD) was 0.2 µM, indicating its potential use in environmental sensing of Hg2+. Further, to explore the potential of QC-AgNPs in biosensing of Hg2+, the biodistribution of nanoparticles was checked by studying their interactions with bovine serum albumin (BSA), a model career protein. Interactions between BSA and QC-AgNPs were explored using UV-Vis, steady-state, time-resolved and synchronous fluorescence spectroscopy. QC-AgNPs caused static quenching of tryptophan fluorescence of BSA with a quenching constant in the order of 108 M-1. The thermodynamic parameters (ΔH and ΔS) suggested predominant involvement of hydrophobic interactions in the binding process of nanoparticles with BSA.