Chemistry Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Biomacromolecules. 2011 Apr 11;12(4):1305-11. doi: 10.1021/bm200031v. Epub 2011 Mar 8.
Highly efficient recyclable antibacterial magnetite nanoparticles consisting of a magnetic Fe(3)O(4) core with an antibacterial poly(quaternary ammonium) (PQA) coating were prepared in an efficient four-step process. The synthetic pathway included: (1) preparation of Fe(3)O(4) nanoparticles via coprecipitation of Fe(2+)/Fe(3+) in the presence of an alkaline solution; (2) attachment of an ATRP initiating functionality to the surface of the nanoparticles; (3) surface-initiated atom transfer radical polymerization (ATRP) of 2-(dimethylamino)ethyl methacrylate (DMAEMA); and (4) transformation of PDMAEMA brushes to PQA via quaternization with ethyl bromide. The success of the surface functionalization was confirmed by FT-IR, thermal gravimetric analysis (TGA), elemental analysis, and transmission electron microscopy (TEM). The PQA-modified magnetite nanoparticles were dispersed in water and exhibited a response to an external magnetic field, making the nanoparticles easy to remove from water after antibacterial tests. The PQA-modified magnetite nanoparticles retained 100% biocidal efficiency against E. coli (10(5) to 10(6)E. coli/mg nanoparticles) during eight exposure/collect/recycle procedures without washing with any solvents or water.
高效可回收的抗菌磁铁矿纳米粒子由带抗菌聚季铵盐（PQA）涂层的磁性 Fe(3)O(4)核组成，通过高效的四步过程制备。合成途径包括：(1)在碱性溶液存在下通过 Fe(2+)/Fe(3+)共沉淀制备 Fe(3)O(4)纳米粒子；(2)将 ATRP 引发官能团附着到纳米粒子表面；(3)表面引发原子转移自由基聚合（ATRP）的 2-(二甲氨基)乙基甲基丙烯酸酯（DMAEMA）；和(4)通过与溴乙烷季铵化将 PDMAEMA 刷转化为 PQA。表面功能化的成功通过傅里叶变换红外光谱（FT-IR）、热重分析（TGA）、元素分析和透射电子显微镜（TEM）得到证实。PQA 修饰的磁铁矿纳米粒子在水中分散，并对外磁场有响应，使得纳米粒子在抗菌测试后易于从水中去除。在没有用任何溶剂或水洗涤的情况下，经过八次暴露/收集/回收处理，PQA 修饰的磁铁矿纳米粒子对大肠杆菌（10(5)至 10(6)大肠杆菌/毫克纳米粒子）保持 100%的杀菌效率。
