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用化学共沉淀法合成了6~12nm的超顺磁性Fe3O4纳米晶体,在室温下用3-氨丙基三乙氧基硅烷(APTES)对其表面氨基化,然后加入Frens法合成的金溶胶,自组装制备了磁性Fe3O4@Au复合纳米粒子.用透射电子显微镜(TEM)、紫外可见吸收光谱(UV-Vis)、傅里叶变换红外光谱(FT-IR)、震动样品磁场计(VSM)等方法对合成的金磁微粒的表面形貌、光学、结构、磁性质等进行表征.结果表明,合成的金磁微粒粒径分布均匀,在15~20nm,磁响应性好.金磁微粒有超顺磁性和易与生物分子结合的特点,以葡萄糖氧化酶(GOx)为模型,详细研究了固定化酶条件及固定化酶的酶学性质.固定化酶的最优条件为:Fe3O4:HAuCl4摩尔比为0.5:1,pH5.5,温度为28℃.固定化后葡萄糖氧化酶耐热性提高,保存时间延长,且能在外部磁场下分离反复使用.
The superparamagnetic Fe3O4 nanocrystals with 6 ~ 12nm were synthesized by chemical coprecipitation. The surface of the superparamagnetic Fe3O4 nanocrystals were aminated with 3-aminopropyltriethoxysilane (APTES) at room temperature, and then the gold sol synthesized by Frens method was added. The magnetic Fe3O4 @ Au composite nanoparticles were prepared by self-assembly and characterized by transmission electron microscopy (TEM), UV-Vis, FT-IR, VSM Methods The surface morphology, optical, structural and magnetic properties of the as-synthesized Au-Mo microparticles were characterized. The results showed that the Au microparticles have a uniform particle size distribution with good magnetic response at 15-20 nm. Paramagnetism and easy to combine with biomolecules, the conditions of immobilized enzyme and the enzymatic properties of immobilized enzyme were studied in detail with glucose oxidase (GOx) as the model.The optimum conditions of immobilized enzyme were as follows: molar ratio of Fe3O4: HAuCl4 Ratio of 0.5: 1, pH5.5, temperature of 28 ° C. Immobilized glucose oxidase increased heat resistance, storage time, and can be separated and reused in an external magnetic field.