Investigation of Antimicrobial Activity and Cytotoxicity of Silver Nanoparticle Synthesized using Dopamine as a Reducing and Capping Agent

We present a study focused on the controlled fabrication of silver nanoparticles (AgNPs) through colloidal synthesis, employing dopamine as a reducing and capping agent. By manipulating the concentration of silver nitrate, the production of spherical AgNPs with distinct particle diameters (16, 24, 48, and 74 nm) was achieved. The investigation extended to the evaluation of AgNPs ' impact on human embryonic kidney cells, revealing a concentration-dependent response. At lower AgNPs concentrations, cell viability remained nearly 100 %, progressively declining with rising AgNPs concentrations. Importantly, the cytotoxic thresholds observed were notably elevated, underscoring the relatively mild to moderate toxicity profile of the nanoparticles. Furthermore, the antimicrobial efficacy of these synthesized AgNPs was probed against E. coli and S. aureus bacterial strains. Notably, the AgNPs exhibited robust antimicrobial activity, with superior performance exhibited by smaller-sized particles compared to larger ones. Impressively, the minimum inhibitory concentration reached as low as 3.5 mu g/mL, indicating their potent antimicrobial potential. The achieved distinct particle diameters, concentration-dependent cytotoxic responses, and potent antimicrobial efficacy against bacterial strains underscore the multifaceted potential of these nanoparticles. These findings contribute valuable insights for their application in diverse fields, from biomedicine to antimicrobial solutions. The study examines dopamine's capacity in reducing silver nitrate and controlling silver nanoparticle size. The synthesized AgNPs, with varying diameters, show low toxicity towards HEK-293T cells. Smaller AgNPs exhibit higher toxicity. Dopamine-modified AgNPs demonstrate intriguing antimicrobial activity against E. coli and S. aureus, with smaller particles more effective. The AgNPs exhibit bacteriostatic effects for over 8 days. image