采用层层自组装技术将聚天冬胺酸和聚乙二胺修饰到磁性纳米粒子表面上,并研究了修饰后的磁件纳米粒子的zeta 电势变化和对蛋白质的吸附.先通过化学共沉淀的方法获得了四氧化三铁磁性纳米粒子,然后利用层层自组装的方法对纳米粒子进行了修饰.用 TEM 表征了纳米粒子的尺寸.用红外光谱表征了修饰过程中磁性纳米粒子表面组成的变化情况.研究了修饰过程对磁性纳米粒子的 zeta 电势的影响.zeta 电势的正负和大小与表面连接的分子的带电性质有关.磁性纳米粒子的等电点接近中性.聚天冬胺酸修饰的磁性纳米粒子的 Zeta 电势为负值.在聚乙二胺溶液的 pH=11 时获得的双层修饰的磁性粒子的等电点接近9,并且等电点随聚乙二胺溶液的 pH 的减小而减小.结果也表明在 pH=7.4 时具有不同表面电荷的磁性纳米粒子通过静电作用选择性地吸附蛋白质.%Magnetic nanoparticles were modified by polyasparticate and poly(ethyleneimine) via layer-by-layer self-assembly. The zeta-potential and protein adsorption of the modified magnetic nanoparticies (Fe3O4) were studied. Magnetic nanoparticles were synthesized by chemical co-precipitation method and then were modified via layer-by-layer self-assembly. The size of the particles was examined by transmission electron microscopy (TEM). Fourier transform infrared (FTIR) measurement was used to confirm the change of composition on the surface ofnanopartilces. The effect of modification on the zeta potential of nanoparticles was disscused. The zeta potential of nanoparticles was related to electric property of molecules on the surface of magnetic nanopartilces. The isoelectric point of magnetic nanoparticles is closely neutral.The zeta potential of polyasparticate-modified magnetic nanoparticles is negative. The isoelectric point of poly(ethyleneimine)-modified magnetic nanoparticles decreased with decreasing pH of PEI solution. The isoelectric point of the modified magnetic nanoparticles is about 9 when pH of PEI solution is 11. At pH 7.4,the magnetic nanoparticles with different charge adsorbed selectively proteins via electrostatic interaction.
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