水溶性有机溶剂对Fe_3O_4磁性纳米粒子过氧化物酶样活性的影响

Effects of aqueous-organic solvents on peroxidase mimetic activity of Fe_3O_4 magnetic nanoparticles

采用化学共沉淀法合成10nm的Fe3O4磁性纳米粒子(MNPs)。以辣根过氧化物酶(HRP)为对照,研究了四氢呋喃、1,4-二氧六环、丙酮、N,N-二甲基酰胺、甲醇和二甲亚砜等6种水溶性有机溶剂对Fe3O4MNPs过氧化物酶样活性的影响。结果表明,在有机溶剂浓度(V/V)为30%～75%时,Fe3O4MNPs相对酶活力迅速下降至近于完全失活。在15%有机溶液中,Fe3O4MNPs的最适反应温度多为50oC,最适反应pH在3.6左右。经15%有机溶液处理后的水相反应酶活显示,Fe3O4MNPs表现出对有机溶剂较强的热稳定性和pH稳定性,且对75%有机溶液也具有良好的稳定性。以上多数性质均优于相同条件下的HRP组,表明Fe3O4MNPs是一种比HRP对水溶性有机溶剂更稳定的过氧化物酶。由于Fe3O4MNPs具有易制备、成本低、易于磁分离和可循环使用的特点,因此其具有替代HRP用于有机催化的应用潜力。

We prepared Fe3O4 magnetic nanoparticles （MNPs） with the size of 10 nm by chemical coprecipitation.The effects of six aqueous-organic solvents,including tetrahydrofuran,dioxane,acetone,N,N-Dimethylformamide,methylalcohol,and Dimethyl Sulfoxide,on peroxidase mimetic activity of Fe3O4 MNPs were studied and compared with that of horseradish peroxidase （HRP）.The relative activity of Fe3O4 MNPs droped sharply as the elevation of organic solvent concentration increased from 30% to 75% （V/V）.In 15% organic solutions, the optimum activity of Fe3O4 MNPs was observed around 50℃, under pH 3.6. After being treated at different temperatures and pH in 15% organic solutions, even under 75% concentration, Fe3O4 MNPs still preserved most of the activity when reacting in aqueous phase. The catalytic performances of Fe3O4 MNPs under given conditions were generally more superior to that of HRP. For it costs lower and it is easy to be prepared and segregated magnetically for recycle, to use the magnetic nanoparticles as a substitution for HRP has potential to be applied into organic catalysis.