超细ZnFe_2O_4纳米晶与蛋白质的相互作用

Ultrafine ZnFe_2O_4 Nanocrystals Interacting with Proteins

水热法制备了超细ZnFe2O4纳米晶,并通过高分辨透射电镜(HRTEM)、XRD和EDX技术对其进行了表征。以牛血清白蛋白(Bovine Serum Albumin,BSA)和牛血红蛋白(Hemoglobin)为模式蛋白,研究了纳米晶在不同pH条件下对蛋白质分子的吸附及其与ζ电势的关系。通过动态光散射(Dynamic Light Scattering,DLS)和傅立叶变换红外光谱(Fourier Transform Infrared,FTIR)技术分别研究了纳米晶吸附蛋白后流体力学直径的变化以及蛋白质构象的变化。结果表明,ZnFe2O4纳米晶对牛血红蛋白的吸附符合静电吸附的规律,而对BSA的吸附则不符合静电吸附的规律。纳米晶吸附牛血红蛋白后主要以单体和三聚体的形式存在,仅存在少量的团聚体,而吸附BSA后完全以团聚体的形式存在。FTIR光谱则显示纳米晶对牛血红蛋白构象的影响大于对BSA构象的影响。在合适的pH条件下,纳米晶对BSA及牛血红蛋白的吸附容量均超过380 mg·g-1,有望应用于蛋白质的高效分离。

Uhrafine ZnFe2O4 nanocrystals were prepared by hydrothermal method and characterized by HRTEM, XRD and EDX techniques respectively. Protein adsorption properties and their correlations to potentials between nanocrystals and protein molecules were investigated under different pH conditions using bovine serum albumin （BSA） and hemoglobin as model proteins. The hydrodynamic size of bare and protein loaded nanocrystals as well as protein conformation changes induced by nanocrystals were respectively studied by dynamic light scattering （DLS） and Fourier transform infrared （FTIR） spectroscopy techniques. Results show that adsorption between nanocrystals and hemoglobin obeys the law of electrostatistic interaction, whereas BSA adsorption behavior is not agreed with such law. After hemoglobin loading, most of nanocrystal-protein systems suspend as monomers and trimers apart from a few aggregates, whereas only aggregates exist after BSA adsorbing onto nanocrystals. FTIR spectroscopy revealed that Hemoglobin suffers more conformational c hanges than that of BSA. In addition, highly protein adsorption capacities exceeding 380 mg .g-1 at appropriate pH potential applications of nanocrystals in protein separation. conditions imply the