<![CDATA[BACKGROUND: Silver nanoparticles (AgNPs) are commonly synthesized by chemical methods; however, these methods often involve toxic chemicals that may limit their biomedical applications. In contrast, pulsed laser ablation in liquid (PLAL) is a clean and chemical-free technique capable of producing highly pure AgNPs. Yet, only limited studies have investigated the structural, optical, antibacterial, and cytotoxicity properties of AgNPs synthesized by PLAL. Therefore, this study was conducted to synthesize pure AgNPs using pulsed laser ablation and evaluate their biomedical activity against bacterial strains and MCF-7 cells.METHODS: The synthesis of AgNPs was done by PLAL technique, and the characterization of nanoparticles were further determined using transmission electron microscopy (TEM), X-ray diffraction (XRD), and Ultraviolet-Visible (UV–Vis) spectroscopy. Antibacterial activity of AgNPs was tested with agar well diffusion method and the cytotoxicity effect was evaluated with MTT assay against the MCF-7 cells.RESULTS: TEM analysis showed semi-spherical AgNPs with an average particle size of 31 nm. XRD analysis showed that the structure was crystalline face-centered cubic with an average crystallite size of 16.8 nm. Peak value of the SPR was recorded at 405 nm and the optical band gap was 2.28 eV. Concentration dependent antibacterial activity was observed for the AgNPs and inhibition zones of 17 mm against Streptococcus mutans and 18 mm against Lactobacillus spp. at highest concentration. Moreover, concentration-dependent cytotoxicity against MCF-7 cells was observed, reaching a maximum inhibition of about 69% at 1000 µg/mL and IC₅₀ of about 90 µg/mL.CONCLUSION: The synthesized AgNPs showed favorable structural and optical characteristics, along with antibacterial and cytotoxic activities. Both effects were concentration-dependent, indicating their potential for further biomedical applications.KEYWORDS: silver nanoparticles, laser ablation, antibacterial activity, MCF-7, cytotoxicity]]>
