Antimicrobial resistance to antibiotics (AMR) is already considered as one of the most concerning global health problems of the 21st century and its burden of deaths threatens to rise dramatically, above those caused by cancer, diabetes and traffic accidents. Metallic nanoparticles (NPs) have attracted much attention as a subject of investigation due to their outstanding properties and have positioned themselves as a promising alternative to antibiotics to combat AMR, Metallic nanoparticles are widely used due to their electrical, thermal, and catalytic properties, although conventional chemical synthesis often introduces toxic byproducts, that may limit their biomedical applications. Laser ablation of solids in liquids (LASL) becomes a cleaner alternative, enabling nanoparticle production without chemical precursors, while offering certain control over nanoparticle size and shape.

The novelty of this work lies in applying laser re-irradiation, a process where nanoparticles undergo additional laser exposure through a capillary tube. Confined laser re-irradiation enables the production of bimetallic nanoparticles, optimizing their structure and composition for improved performance.

Comprehensive characterization techniques, including TEM, FESEM, SAED, HRTEM, EDS and UV-Vis spectroscopy, confirmed the high purity, crystallography and composition of the synthesized bimetallic nanoparticles. Biological tests demonstrated potent antibacterial activity of bimetallic nanoparticles, while cytotoxicity assays showed that they are still safe for human fibroblast cells.

These findings highlight laser re-irradiation as a promising technique for producing high-quality bimetallic nanoparticles, paving the way for their use in medical, environmental, and catalytic applications, where purity and enhanced performance are critical.