Bio-inspired decoration of Ag nanoparticles on eggshell-derived hierarchical CaO-based flower-like architectures for enhanced antibacterial, photocatalytic, and hemocompatible applications

AgNP-containing nanocomposites were synthesized via green synthesis using grapevine leaf extract, from raw free-range eggshell (FR-ES), calcined free-range eggshell (C-FR-ES), raw market eggshell (M-ES), and calcined market eggshell (C-M-ES), yielding nanocomposites G-FR-ES, G-C-FR-ES, G-M-ES, and G-C-M-ES (G denoting AgNP decoration). Leaf pigment profiles were assessed colorimetrically, and phytochemical content was elucidated by GC-MS. XRF, FTIR, XRD, and SEM-EDX confirmed conversion of calcined eggshells into AgNP-decorated CaO-based flower-like architectures. The MIC against P. aeruginosa was 10 mg/mL for all nanocomposites, and against E. coli was 20 mg/mL (10 mg/mL for G-FR-ES). In the agar well diffusion assay, inhibition zones against E. coli were 14.1 ± 0.17, 7.1 ± 0.12, 14.0 ± 0.10, and 5.8 ± 0.47 mm, and against P. aeruginosa were 13.1 ± 0.12, 7.9 ± 0.12, 15.1 ± 0.23, and 5.1 ± 0.12 mm, respectively, with one-way ANOVA/Tukey’s test confirming significant differences ( p < 0.05). Most samples exhibited mild hemolysis, while C-FR-ES and G-C-FR-ES showed hemolysis below 2% . In the photocatalytic assay, G-C-M-ES achieved 96% methylene blue degradation, with rate constants of 0.176–0.822 h⁻¹. These results demonstrate a sustainable route from waste eggshells to multifunctional, AgNP-decorated CaO-based flower nanocomposites with antibacterial, hemocompatible, and photocatalytic activity.