Laser-assisted method for preparation of nanocomposites based on magnetite and noble metals for biomedical applications

Pulsed laser ablation in liquids (PLAL) has been developed as a robust method for producing multi-element nanoparticles such as metal alloys. This has sparked considerable interest in furthering our knowledge of nanoparticle formation during PLAL, with the aim of improving control over product structure and broadening the variety of compositions achievable with this approach. In this paper, we present the fabrication of magneto-plasmonic nanoparticles based on Fe₃O₄/Au nanocomposite utilizing an infrared nanosecond laser for laser ablation in a liquid medium. This innovative and adaptable approach enables us to create multi-element nanosystems under non-equilibrium conditions. We thoroughly characterized the Fe₃O₄/Au nanocomposites using a variety of techniques, including electron microscopy, elemental analysis, X-ray diffraction, and ultraviolet–visible absorption spectroscopy. The XRD results revealed a crystalline structure composed of Au NPs and Fe₃O₄ NPs with no impurities present. Furthermore, increasing the laser energy also resulted in a red shift in the maximum exciton absorption (λ_max), a result of the quantum confinement effect impacting the generation of electron–hole (e–h) carriers. Furthermore, our TEM images revealed a color gradient in the spherical shape, which became more pronounced with higher laser ablation power. Subsequently, we assessed the antibacterial activity of the synthesized Fe₃O₄/Au nanocomposite against five distinct species of bacteria using agar plate diffusion methods. This was followed by minimum inhibition concentration determination and measuring reactive oxygen species (ROS) within the treated bacterial pathogens. The findings of our research position identify laser-synthesized Fe₃O₄/Au nanocomposite structures as promising candidates for a variety of biomedical applications.