Green Synthesis of Curcuminoids-Enriched Trimetallic Nanoparticles Stabilised by Chitosan/Collagen Nanocomposites against Foodborne Pathogens

The integration of natural bioactive components with multiple metal nanoparticles in bionanocomposites will enhance their biological activities. In this study, a curcuminoid-rich extract was used as a capping and reducing agent for trimetallic nanoparticles (Ag@TiO2@ZnO), which were stabilized using biopolymers (chitosan and collagen). The formulated nanocomposite-based trimetallic nanoparticles were prepared using different ratios of curcuminoid extract (1%, 3%, and 5% w/w), labelled as CR-1, CR-2, and CR-3, respectively. Their physicochemical properties were characterized using UV-vis, FTIR and DLS. The morphological structure was characterized using FE-SEM with EDX, HR-TEM, and SAED. Additionally, their potential antimicrobial activities were evaluated against various strains of selected foodborne pathogenic bacteria and fungi. The physicochemical characterization confirmed that the curcumin ratio influenced the size and shape of the trimetallic nanoparticles, as well as the network structure of the stabilized biopolymer matrix. Among the formulations, CR-2 exhibited the most potent activity against all tested foodborne microorganisms of pathogenic bacterial strains with MIC ranges of 0.4 to 0.9 mg/mL and mycotoxigenic fungal strains with MIC of 0.2 to 1.1 mg/mL, along with excellent cytocompatibility with human skin fibroblasts (BJ-1), showing a cell viability of 96.17%. The nanoscale size of CR-2 was recorded between 52 and 11 nm. The average zeta potential was recorded as 23 ± 4 mV, indicating high colloidal stability. The findings highlight the high potential of these green-synthesized trimetallic nanoparticles, particularly CR-2, for commercial development in safe therapeutic and cosmetic formulations, as well as potential applications in agriculture and food safety.