Multimodal copper nanoparticle platforms via green synthesis for enhanced photocatalytic and biomedical performance

This study reports the sustainable green synthesis of copper nanoparticles (CuNPs) using Diospyros malabarica leaf extract and evaluates their multifaceted therapeutic and environmental applications. Characterization via UV-Vis spectroscopy confirmed an absorption peak at 250 nm, while XRD and SEM analyses revealed crystalline, irregular polygonal structures with an average crystal size of 24.825 nm and a particle diameter of 65.22 nm, respectively. FTIR spectra identified phenolic and protein functional groups as the primary reducing and stabilizing agents. VSM analysis confirmed superparamagnetic behaviour with negligible hysteresis at room temperature. Critically, the CuNPs demonstrated superior functional performance: photocatalytic assays showed 89.53% degradation of methyl red within 120 min under UV light. Antioxidant testing revealed a potent DPPH radical scavenging activity that was concentration-dependent with recorded inhibitions of 61.54%, 66.35%, and 71.15% at concentrations of 100, 200, and 400 µg/mL, respectively, compared to catechin, which showed inhibition rates of 72.12%, 76.92%, and 86.42%. Furthermore, antimicrobial assays yielded zones of inhibition of 11 mm against E. coli and S. aureus , while anti-inflammatory trials showed a 3.19% after 1 h to 77.15% after 6 h reduction in AAPH-induced erythrocyte haemolysis at 50 μg/mL concentration. In contrast, CuNPs at 100 μg/mL showed an increase from 2.24% to 59.42% during the same timeframe. These quantitative findings position D. malabarica -mediated CuNPs as a high-performance, versatile platform for biomedical and water-remediation technologies.