Biogenic selenium nanozymes from pomegranate peel extract: Size-tunable catalase/ SOD-mimetic selectivity underpinning dual antibacterial-antioxidant function

This study details the green synthesis of selenium nanoparticles (SeNPs) using pomegranate peel extract, producing two variants: SeNPs-1 and SeNPs-2. The formation of SeNPs was confirmed through color change, scanning electron microscopy (SEM), and dynamic light scattering (DLS), with mean particle sizes of 65.0 ± 54.7 nm and 61.7 ± 22.4 nm, respectively. UV–VIS spectroscopy revealed absorption peaks at 372 nm for SeNPs-1 and 272 nm for SeNPs-2, while X-ray diffraction (XRD) confirmed their crystallinity. Fourier transform infrared spectroscopy (FTIR) was used to analyze the functional groups crucial for SeNPs stabilization. Energy-dispersive X-ray spectroscopy (EDX) showed selenium contents of 80% in SeNPs-1 and 40% in SeNPs-2. Zeta potential measurements indicated moderate stability, especially for SeNPs-1. The nanoparticles demonstrated significant antibacterial activity against Staphylococcus aureus and Klebsiella pneumoniae, as well as strong antioxidant potential in DPPH assays. This research is among the first reports demonstrating the enzyme-mimicking properties of PPE-mediated SeNPs, as particle size determines whether the particles act more like catalase or SOD, suggesting their potential as antimicrobial and antioxidant agents.