Characterization and antimicrobial assessment of phytogenic synthesized selenium nanoparticles using leaf extract of...

An environmentally friendly approach to treating microbial diseases has become necessary due to growing concerns about the adverse consequences of traditional antibiotics. The eco-friendly synthesis of selenium nanoparticles using the leaf extract of Abies spectabilis, a significant medicinal plant classified as near threatened, is reported for the first time in this study. Selenium nanoparticles (SeNPs) were selected due to their unique combination of high biological activity, enhanced surface area, bioavailability, low toxicity and low cost as compared to other metallic nanoparticles. In this green synthesis method, the leaf extract of Abies spectabilis acts as a natural reducing and stabilizing agent for the synthesis of selenium nanoparticles. The produced nanoparticles were thoroughly characterized and assessed for their anti-microbial potency. An absorbance peak at 280 nm in the UV-Vis spectrophotometry indicated the synthesis of Abies spectabilis selenium nanoparticles (AS-SeNPs). Functional groups that aid in the reduction and stability of SeNPs were verified by FTIR analysis. The Zeta sizer, TEM, and SEM-EDX examination confirmed the high elemental purity of the synthesized SeNPs, which exhibited a predominantly spherical morphology. The particle size distribution ranged from 25 nm to 275 nm with an average size of 122 nm. The crystalline characteristics of AS-SeNPs were evaluated using X-ray diffractometry, which confirmed their well-defined, stable structural nature. The anti-bacterial assay of the synthesized AS-SeNPs showed significantly better inhibition against both Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli) bacterial strains, with zones of inhibition ranging from 18.00 ± 4.36 mm to 21.33 ± 4.73 mm and MIC values ranging from 0.8 mg mL^- 1 to 1.6 mg mL^- 1. Similarly, anti-fungal activity against Aspergillus niger and Candida albicans demonstrated dose-dependent intriguing potential of AS-SeNPs with zones of inhibition ranging from 25.33 ± 2.5 mm to 22.33 ± 6.6 mm. A synergistic relationship between selenium nanoparticles and plant-derived bioactive chemicals markedly increased the broad-spectrum anti-bacterial and anti-fungal activity of SeNPs when compared to the plant extract alone. These green-synthesized AS-SeNPs hold significant potential for applications in phytomedicine, anti-microbial coatings, wound-healing formulations, food preservation, and pharmaceutical nanotechnology, offering an environmentally responsible strategy for combating microbial infections.