Quercetin biomolecule-stabilized gold nanoparticles: a synthesis-to-biotherapy platform for antibacterial, anti-hemolytic, anti-inflammatory, and anticancer applications

This study aimed to synthesize gold nanoparticles (GNPs) using quercetin (QU) biomolecule as a natural reducing and stabilizing agent and to evaluate its biointerface and biotherapeutic potential. The bio/nano-formulated QU-GNPs with crystalline structure from XRD pattern showed a maximum absorption peak of 532 nm by UV–Vis analysis. The spherical shape, average particle size of 33.1 ± 9 nm, and zeta potential of -26.9 mV were obtained by FE-SEM and DLS study for QU-GNPs. Elemental composition and mapping analysis of QU-GNPs, conducted through EDX, unequivocally identified the presence of the primary constituent elements: gold, carbon, and oxygen. This observation definitively corroborates the successful surface functionalization of the GNPs with QU moieties. Concurrently, TEM characterization ascertained an average particle diameter of 21.93 nm for the QU-GNPs. These GNPs displayed significant antioxidant activity with a DPPH radical scavenging percentage of 81.7% at 600 µg/mL. The incubation of red blood cells (RBCs) with QU-GNPs at 800 µg/mL showed hemolysis of less than 2% (1.6%), indicating its non-hemolytic effect. Also, QU-GNPs at 100 µg/mL protected the integrity of the RBC membrane by 95.1% and at a concentration of 400 µg/mL, strongly blocked the protein denaturation by 90.5%, confirming its high anti-inflammatory effects. The QU-GNPs had a significant cytotoxic effect against MCF-7 cancer cells (293.6 µg/mL), without any toxic potential on normal fibroblast cells. Additionally, these GNPs exhibited high antibacterial activity. Therefore, according to these findings, biosynthesized QU-GNPs with promising biological properties and bio-therapeutic potential could be considered as a novel bio-safe bio/nano-compound warranting further in vivo investigations for future therapeutic applications.