Scholarlink

<p>Antimicrobial nanomaterials that can be magnetically recovered are attractive for healthcare and environmental uses, yet performance hinges on how silver (Ag) is dispersed on magnetic supports. Here we elucidate structure–property relationships in Fe<sub>3</sub>O<sub>4</sub>/Ag nanocomposites with 3, 5, and 10 wt% Ag prepared by a co-precipitation/reduction route. Phase analysis by X-ray diffraction confirmed inverse-spinel Fe<sub>3</sub>O<sub>4</sub> with face-centered-cubic Ag, and energy-dispersive X-ray (EDX) elemental mapping verified Ag as finely dispersed, surface-localized domains, most uniform at ~ 5 wt% Ag. Transmission electron microscopy (TEM) provided a number-based size distribution centered at µ = 17.1&#xa0;nm. Vibrating-sample magnetometry (VSM) showed superparamagnetic behavior with saturation magnetization decreasing with Ag loading (55.37, 15.26, 6.35 emu/g for 3, 5, 10 wt%, respectively) but remaining sufficient for rapid magnetic separation. Antibacterial activity against <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Staphylococcus aureus</i> (<i>S. aureus</i>) was quantified by broth microdilution (MIC/MBC): the 5 wt% sample exhibited the lowest values (<i>E. coli</i>: MIC 50&#xa0;µg mL<sup>− 1</sup>, MBC 100&#xa0;µg mL<sup>− 1</sup>; <i>S. aureus</i>: MIC 100&#xa0;µg mL<sup>− 1</sup>, MBC 200&#xa0;µg mL<sup>− 1</sup>), consistent with the mapping-validated Ag dispersion. Antioxidant performance assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay showed concentration-dependent scavenging (28%, 52%, 78% at 125, 250, 500&#xa0;µg mL⁻¹). Collectively, the data indicate that ~ 5 wt% Ag is the operational optimum. At this loading, accessible Ag “hot spots” are maximized without sacrificing magnetic recoverability. This yields a practical design rule for magnetically retrievable antimicrobial/antioxidant nanocomposites for environmental use and (pending biocompatibility) potential biomedical applications.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Magnetically Recoverable Fe3O4/Ag Nanocomposites with Enhanced Antibacterial and Antioxidant Activities: Toward Biomedical and Environmental Applications

  • 期刊论文

  • 发表日期：

    2025年12月17日

查看全文
  • Zaid Alnewaini,
  • Hasan Raheem Khudhur,
  • Ali Abbasi,
  • Nadir M. Nanakali,
  • Mohammad Almasi Kashi,
  • Masoomeh Sadat Fin,
  • Hossein Khojasteh,
  • Kamran Heydaryan

摘要

Antimicrobial nanomaterials that can be magnetically recovered are attractive for healthcare and environmental uses, yet performance hinges on how silver (Ag) is dispersed on magnetic supports. Here we elucidate structure–property relationships in Fe3O4/Ag nanocomposites with 3, 5, and 10 wt% Ag prepared by a co-precipitation/reduction route. Phase analysis by X-ray diffraction confirmed inverse-spinel Fe3O4 with face-centered-cubic Ag, and energy-dispersive X-ray (EDX) elemental mapping verified Ag as finely dispersed, surface-localized domains, most uniform at ~ 5 wt% Ag. Transmission electron microscopy (TEM) provided a number-based size distribution centered at µ = 17.1 nm. Vibrating-sample magnetometry (VSM) showed superparamagnetic behavior with saturation magnetization decreasing with Ag loading (55.37, 15.26, 6.35 emu/g for 3, 5, 10 wt%, respectively) but remaining sufficient for rapid magnetic separation. Antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was quantified by broth microdilution (MIC/MBC): the 5 wt% sample exhibited the lowest values (E. coli: MIC 50 µg mL− 1, MBC 100 µg mL− 1; S. aureus: MIC 100 µg mL− 1, MBC 200 µg mL− 1), consistent with the mapping-validated Ag dispersion. Antioxidant performance assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay showed concentration-dependent scavenging (28%, 52%, 78% at 125, 250, 500 µg mL⁻¹). Collectively, the data indicate that ~ 5 wt% Ag is the operational optimum. At this loading, accessible Ag “hot spots” are maximized without sacrificing magnetic recoverability. This yields a practical design rule for magnetically retrievable antimicrobial/antioxidant nanocomposites for environmental use and (pending biocompatibility) potential biomedical applications.