磁性Fe_3O_4/Ag复合纳米粒子制备与抗菌性能

Preparation and Antibacterial Activity of Magnetic Fe_3O_4/Ag Composite Nanoparticles

在3-氨丙基三乙氧基硅烷(APTES)功能化修饰后的Fe3O4纳米粒子溶液体系中,加入乙酸银使游离态银离子充分吸附在磁粒的表面,与氨基化基团形成配位化合物,再利用甲酸钠将配位银离子还原为银,制成磁性Fe3O4/Ag复合纳米粒子。采用紫外吸收可见光谱(UV-Vis)、电子能谱仪(EDS)、透射电子显微镜(TEM)和超导量子干涉仪(SQUID)等方法对复合粒子的形态、结构、组成以及磁学性质进行表征。同时,采用大肠杆菌和金黄色葡萄球菌对磁性Fe3O4/Ag复合纳米粒子的抗菌性能进行研究。结果表明:合成的复合粒子平均粒径为30 nm,室温下磁化强度为2.0(A·m2)/kg;磁性Fe3O4/Ag复合纳米粒子对大肠杆菌和金黄色葡萄球菌具有显著地抑制效果,指定实验条件下在24 h后两种细菌的存活量在0.11×103(CFU)以下,进一步提高磁性Fe3O4/Ag复合纳米粒子用量,大肠杆菌存活量几乎100%减灭。本研究方法为制备具有外场响应功能(如磁场响应)的新型纳米生物抗菌材料提供了很好的范例。

Magnetic composite nanoparticles Fe3O4/Ag were prepared by adding silver acetate into （3-aminopropyl）triethoxysilane （APTES）-coated Fe3O4 nanoparticles solution,silver ions were absorbed on the surface and formed a coordination compound with amino groups,and finally the complexed silver ions were reduced by sodium formate to generate magnetic Fe3O4/Ag composite nanoparticles.The morphology,microstructure,composition and magnetic properties of the Fe3O4/Ag nanoparticles were characterized by ultraviolet-visible spectroscopy （UV-Vis）,energy dispersive spectroscopy （EDS）,transmission electron microscopy （TEM） and superconducting quantum interference device （SQUID） magnetometry.And the antibacterial activities of the composites were investigated by E.coli and S.aureus as test bacterial spawn.The results show that as-obtained magnetic silver-containing nanoparticles possess a saturation magnetization （Ms） of about 2.0 （Am2）/kg,and their average diameter is about 30 nm; meanwhile,the antibacterial tests show the composites demonstrate great antibacterial activity for restraining these two bacteria.Under controlled experiments,the number of these two bacteria id both under 0.11 × 103 （CFU） after 24 h test.Further test by adding more nanoeomposites could sterilize nearly 100％of the E.coli.The magnetic and antibacterial nanocomposite fabrication process provides a good example for preparing novel biological antibacterial material,which is sensitively responded to external field （such as magnetic field）.