Reutilizing Flavonoids from Agricultural By-Products for In Situ Generation and Immobilization of AgNPs on Silk...

The utilization of agro-byproducts for textile dyeing and finishing is strongly suggested to meet sustainability and cost-efficiency objectives. Despite recently proliferating studies, three major issues hinder the industrialization of such a technique: identifying reasonable bio-resources, ensuring compatibility between agro-byproducts and textile substrates, and achieving satisfactory color depth, functionality, and durability. This research introduces an approach that forms and fixes silver nanoparticles (AgNPs) on silk using three representative flavonoids (FLs)-Quercetin (QUE), Baicalin (BAI), and Rutin (RUT)-through a single-step in situ bio-reduction. Results demonstrate that FLs-synthesized AgNPs@silk generates attractive spectra of hues, varying from pale cream-brown to deep golden-brown. Using an equivalent quantity of FLs, the color intensity of silk descends in QUE-Ag@silk > BAI-Ag@silk > RUR-Ag@silk, due to the decreasing reactivity and binding affinity of FLs to silk. SEM reveals uniformly distributed spherical AgNPs in dimensions between 20 and 40 nm on silk and the dimension inversely correlates with FLs concentration while being directly proportional to silver nitrate. The modified silk exhibits remarkable antimicrobial performance (>98% pathogen elimination) and exceptional wash resistance (>90% reduction both of E. coli and S. aureus after ten cycles of washing). Additionally, the FLs-synthesized AgNPs provide silk with superior UV shielding capability. This study stems from environmental awareness and sustainable production of AgNPs by FLs, ready for developing hygienic and therapeutic textile materials.