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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.

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.