LAUSR

Recently, the development of "green" methods for fabrication of silver nanoparticles (Ag‐NPs) has been emphasized, in view of their environmental safety, feasibility, and low cost. In this study, a serine protease, EuP‐82 from Euphorbia cf. lactea latex, was used to fabricate silver chloride nanoparticles (AgCl‐NPs) in phosphate‐buffered saline (pH 7.2), under the influence of visible light. The fabricated nanoparticles had a maximal surface plasmon resonance absorption peak at 435 nm. The size of the AgCl‐NPs, estimated by scanning electron microscopy, was 57 ± 14.7 nm. Energy dispersive X‐ray spectroscopy, X‐ray absorption spectroscopy, and X‐ray diffraction analysis confirmed that the fabricated Ag‐NPs were of the AgCl type. The fabricated nanoparticles had antioxidant activity, scavenging DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) radicals with IC50 of 204 ± 1.8 μg/mL. The fabricated AgCl‐NPs had broad‐spectrum in vitro antimicrobial activities, acting against the Gram‐positive bacteria Staphylococcus aureus, methicillin‐resistant S. aureus (MRSA), and Bacillus cereus, and the Gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa. AgCl‐NPs also showed antifungal activity against Candida albicans and C. tropicalis. In addition, AgCl‐NPs showed antiprotozoal activity against Giardia lamblia, with IC50 202 ± 2.1 μg/mL. Based on the biological activities of the fabricated AgCl‐NPs, they have the potential for widespread application in medicine and industry.