Selenium nanoparticles: effect of autoclave treatment on size, shape, phase and antimicrobial properties

Amorphous selenium nanoparticles have been synthesized by pulsed laser ablation in liquids. After undergoing a thermal treatment at 121°C for 60 minutes, the amorphous nanoparticles crystallized into trigonal ones. The antimicrobial properties of both amorphous and trigonal nanoparticles have been compared; and the amorphous ones displayed better antibacterial and antifungal properties compared to the trigonal ones. Specifically, Methicillin-resistant Staphylococcus aureus (MRSA), Ampicillin-resistant Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Candida albicans were almost completely inhibited in the presence of amorphous selenium nanoparticles at 0.025 microgram/ml concentrations after 24 hours of in vitro culture, compared to controls (no nanoparticles). In summary, such a high sensitivity of these bacterial and fungal strains to low concentrations of amorphous selenium nanoparticles warrants further investigation to develop efficient anti-bacterial and anti-fungal treatments.