磁性核壳Ag/PDA@SiO2@CoFe2O4复合纳米材料的制备、表征及其抑菌性能研究

采用溶剂热法制备单分散的CoFe₂O₄亚微米球, 分别用正硅酸乙酯(TEOS)和多巴胺(DA)为前体通过溶胶-凝胶法和自聚合法对CoFe₂O₄核表面进行修饰形成具有多层核壳结构的PDA@SiO₂@CoFe₂O₄, 最外层为聚多巴胺(PDA)。采用原位还原法在PDA表面沉积均匀的银纳米粒子, 合成Ag/PDA@SiO₂@CoFe₂O₄磁性复合粒子。采用透射电子显微镜(TEM)、X射线粉末衍射(XRD)、X射线光电子能谱分析(XPS)、振动探针式磁强计(VSM)和电感耦合等离子发射光谱仪(ICP-OES)对样品的形貌、结构等进行表征, 并研究其对大肠杆菌(E.Coli)和金黄色葡萄球菌(S.Aureas)的抑菌性能。结果表明, 当Ag浓度在0.6 mg/mL时, Ag/PDA@SiO₂@CoFe₂O₄对E.Coli和S.Aureas的抑菌率均在92%以上。除了优异的抑菌性能, 它具有很强的磁性, 可以通过外加磁场回收利用。

Preparation,Characterization and Antimicrobial Activity of Core-satellite Ag/PDA@SiO2@CoFe2O4 Magnetic Composites

Monodisperse submicron CoFe₂O₄ spheres were prepared by solvothermal method. Polydopamine-coated silica@CoFe₂O₄ composite particles were synthesized by combination of Sol-Gel process and in situ self-polymerization method, in which tetraethyl orthosilicate (TEOS) and dopamine were used as the precursor for silica and polydopamine (PDA), respectively. The PDA@SiO₂@CoFe₂O₄ composites had a multilayer core-shell structure with PDA as the outermost layer shell. Then, numerous of silver nanoparticles were assembled on the surface of PDA@SiO₂@CoFe₂O₄ via the reduction of Ag⁺ by the surface PDA on the composites. The morphology, structure, and composition of the composites were characterized by transmission electron microscope (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectrometry (XPS), vibrating sample magnetometry (VSM), and inductively coupled plasma optical emission spectrometry (ICP-OES). Antibacterial experiments indicated that the as-prepared composites could restrict up to 92% Escherichia Coli (E.Coli) and Staphylococcus Aureus (S.Aureas) at 0.6 mg/mL Ag. In addition, the composites showed a strong magnetic response to an externally applied magnetic field, so it could be reused.