en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <div class="WordSection1" style="text-align: justify;"><span style="line-height:1;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><b><span style="color:black">Background:</span></b><span style="color:black"> In recent years, the antimicrobial properties of nanoparticles have received significant attention due to increasing bacterial resistance to conventional antibiotics. In this study the antibacterial effects of green-synthesized silver nanoparticles with chemically synthesized silver nanoparticles have been comprised.</span><br> <b><span style="color:black">Methods:</span></b> <span style="color:black">The physicochemical properties of the synthesized nanoparticles </span><span style="color:black">were evaluated through Ultraviolet-Visible (UV-Vis) spectrophotometry, Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive X-ray Analysis (EDAX)</span><span style="color:black"> and antimicrobial activity</span><span style="color:black"> by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC</span><span style="color:black">) values.</span><span style="color:black"></span><br> <b><span style="color:black">Results:</span></b><span style="color:black"> DLS analysis revealed average sizes of 72.8 nm and 124.8 nm for green-synthesized and chemically synthesized AgNPs, respectively. FESEM images showed spherical shapes, while EDAX confirmed the presence of silver, carbon, and oxygen in the nanoparticles. Antimicrobial testing (MIC and MBC) showed that green-synthesized AgNPs exhibited stronger antibacterial activity than chemically synthesized ones. For <i>Escherichia coli</i>, the MIC and MBC for green-synthesized AgNPs were 0.028 mg</span><span style="color:black">/</span><span style="color:black">mL and 0.056 mg</span><span style="color:black">/</span><span style="color:black">mL, respectively, compared to 0.125 mg</span><span style="color:black">/</span><span style="color:black">mL and 0.25 mg</span><span style="color:black">/</span><span style="color:black">mL for chemically synthesized AgNPs. Similarly, for <i>Staphylococcus aureus</i>, the MIC and MBC values for green-synthesized nanoparticles were 0.226 mg</span><span style="color:black">/</span><span style="color:black">mL, while chemically synthesized nanoparticles had MIC and MBC values of 0.125 mg</span><span style="color:black">/</span><span style="color:black">mL and 0.25 mg/mL. </span><br> <b><span style="color:black">Conclusion:</span></b><span style="color:black"> These results demonstrated a higher antimicrobial potential of plant-mediated silver nanoparticle synthesis over chemical methods, especially against Gram-negative bacteria.</span></span></span></span><br> <span style="page:WordSection1"><span style="font-size:9pt"><span style="line-height:normal"><span style="tab-stops:72.05pt"><span style="font-family:Gulliver"><span style="color:black"></span></span></span></span></span></span></div> <div aria-label="Page Break" class="cke_pagebreak" contenteditable="false" data-cke-display-name="pagebreak" data-cke-pagebreak="1" style="page-break-after:always" title="Page Break"></div> Silver nanoparticles, Green synthesis, Agrimonia eupatoria L, Antibacterial activity, 175 181 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-102-7&slc_lang=en&sid=1 Sama Bahraminezhad Samabahram1376@gmail.com 0009-0000-7275-9022 No Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Mohammad Reza Mehrasbi zmehr@zums.ac.ir 0000-0002-9251-4513 No Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Pegah Homauoni pegahhomayooni@gmail.com 0000-0002-4333-6845 No Department of Food Safety and Hygiene, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Zohre Farahmandkia zfarahmand@zums.ac.ir 0000-0002-9022-4969 Yes Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran.