【作者】 李强；

【导师】 黄新堂；

【作者基本信息】 华中师范大学 ， 凝聚态物理， 2014， 博士

【摘要】 纳米材料与蛋白质之间的相互作用将影响到生物体对纳米材料的各种生物反应,这些反应包括生物毒性、生物相容性、细胞识别、细胞摄取等多个方面。当纳米材料暴露在生理环境中,与蛋白质的相互作用会在纳米材料的表面形成一层"Protein Corona",显著改变生物体对纳米材料的识别,使得纳米材料的生物性质不同于纳米材料本身。因此,纳米材料与蛋白质的相互作用是一种很重要的生物学性质,无论对于生物相容性研究或者是生物安全性研究,都需要认识纳米材料与蛋白质的相互作用性质。在纳米生物技术领域,纳米材料在药物载体、基因载体、蛋白质分离纯化以及生物传感器等许多领域都有广泛的应用。在这些领域,纳米材料与蛋白质的相互作用将显著影响纳米材料的应用前景和应用性能,对于纳米材料在生物技术领域的应用研究同样具有重要意义。铁氧化物在药物载体、肿瘤热疗、磁共振成像以及蛋白质分离等多个生物技术领域具有广泛的应用前景。为了进一步扩展这类材料在生命科学领域的应用,有必要研究铁氧化物纳米材料与蛋白质分子的相互作用性质及其机理。基于以上思想,本论文研究了铁氧体和α-Fe2O3两种铁氧化物纳米材料与蛋白质之间的相互作用性质。主要内容如下：1.通过统一的水热法制备了NiFe2O4, CoFe2O4, ZnFe2O4和Ni0.5Co0.5Fe2O4四种铁氧体纳米晶。先按化学计量比的要求配制混合溶液,然后用氨水使金属离子共沉淀成氢氧化物混合溶胶。在190℃的水热条件下反应10小时,得到目标产物。水热制备的纳米晶均为粒径10纳米左右的球形颗粒。XRD分析表明晶型均为尖晶石结构。EDX元素分析证实纳米晶的元素组成与目标产物的元素组成一致。纳米晶的比表面积逼近理论比表面积,说明纳米晶的分散性非常好。2.研究了铁氧体纳米晶与牛血清蛋白(BSA)和牛血红蛋白之间的相互作用。Zeta电势分析发现,BSA与四种纳米晶之间的吸附都不符合静电吸附的规律。而血红蛋白与NiFe2O4, CoFe2O4和ZnFe2O4三种纳米晶之间的吸附符合静电吸附的规律,但与Ni0.5Co0.5Fe2O4纳米晶之间的吸附不能完全用静电相互作用来解释。通过动态光散射(DLS)研究还发现,蛋白质吸附能够导致纳米晶团聚。FTIR分析表明,蛋白质的构象由于纳米晶和蛋白质之间的相互作用而发生改变。3.采用水热法制备了不同形貌的α-Fe2O3纳米结构。通过乙酸钠的调节作用,成功制备了分级结构的α-Fe2O3微米球和α-Fe2O3的纳米颗粒。通过水热的方法还制备了Ti4+掺杂的α-Fe2O3纳米颗粒。对所有的样品进行了N2吸附-脱附分析,结果显示,α-Fe2O3纳米颗粒的比表面积大于分级结构的微米球,而Ti4+掺杂对纳米颗粒的比表面积的影响很小。4.形貌会影响α-Fe2O3纳米结构对蛋白质的吸附行为。所有分级微米球结构的α-Fe2O3对BSA和牛血红蛋白都没有吸附能力。只有α-Fe2O3的纳米颗粒才能吸附蛋白质。Zeta电势分析显示这种吸附不符合静电吸附的特点。Ti4+掺杂也是影响α-Fe2O3纳米颗粒蛋白质吸附行为的重要因素。掺杂的α-Fe2O3纳米颗粒只有在超声波的作用下才能吸附蛋白质,而在不超声的情况下,完全没有蛋白质吸附能力。作为对比,纯α-Fe2O3纳米颗粒能够直接吸附蛋白质,无需超声波的辅助。此外,掺杂的α-Fe2O3纳米颗粒的蛋白质吸附容量也显著高于不掺杂的纳米颗粒。更多还原

【Abstract】 Interaction with protein is a key factor determining the biological responses to nanomaterials, including biological toxicity, biocompatibility, cellular recognization, cellular uptake etc. When nanomaterials are exposed to biological medium, the interactions with protein will lead a "protein corona" covering on the surface of nanomaterials. This protein corona will modify the biological identity and make the biological behavior different to the nanomaterials itself. For this reason, protein-nanomaterial interaction is an important biological propety which should be understood in order to evaluate nanomaterial biocompatibility or biosafety. In the nanobiotechnology field, nanomaterials have potential to be applied in drug delivery, genic carrier, protein purification as well as biosensor etc. In this case, protein-nanomaterial interactions will significantly affect the performance of nanomaterials. Therefore, the applications of nanomaterials in biological field also require the knowledge on protein-nanomaterial interaction.Iron oxides nanostructures have potential applications in biotechnology field that including magnetic drug carrier, hyperthermia application, MRI contrast agent and protein separation etc. In order to extend the biological applications of iron oxides nanostructures, the interactions with protein and the associated mechanism should be investigated. For above mentioned viewpoint, this thesis focuses on protein interaction behaviors of two class of important iron oxides nanomaterials-ferrite and hematite. The main works are detailed as follows:1. Ferrite nanocrystals NiFe2O4, CoFe2O4, ZnFe2O4and Nio.5Co0.5Fe2O4were prepared by hydrothermal method. Stoichiometric reagents were first dissolved in water, then co-preciptate by ammonia water. The colloid precipitation was hydrothermally treated at190℃for10hours. The obtained products were spherical nanocrystal with diameter about10nm. XRD analysis confirmed that all the products were spinel crystalline structure. The EDX analysis indicated that the elemental contents were consistent with the formula NiFe2O4, CoFe2O4, ZnFe2O4and Nio.5Coo.5Fe2O4. Specific area of nanocrystals was determined by BET method. The results showed that the BET of nanocrystals approximated to their theoretical values.2. The mechanism on protein adsorption to ferrite nanocrystals were investigated by Zeta potential technology. Adsorption behaviors between BSA and four nanocrystals can not be attributed to electrostatic interactions. Hemoglobin adsorbed to NiFe2O4, CoFe2O4and ZnFe2O4nanocrystals via electrostatic interactions. But, the adsorption between hemoglobin and Ni0.5Co0.5Fe2O4was not consistent with electrostatic interactions. Protein adsorption can lead to nanocrystals aggregation, which has been detected by Dynamic Light Scattering (DLS) technique. FTIR showed that protein conformation had been changed due to the nanocrystal-protein interactions.3. Different morphological α-Fe2O3nanostructures were prepared by hydrothermal method. Under the mediation of sodium acetate, α-Fe2O3hierarchical microsphere and α-Fe2O3nanoparticle can be obtained. Hydrothermal method was also applied to prepare Ti4+doped α-Fe2O3nanoparticles. All the products were analysis by N2adsorption-desorption experiment and the BET values were acquired. Results showed that α-Fe2O3nanoparticle possessed higher specific area than hierarchical microsphere morphology. The Ti4+dopant had very little impact on the specific area of α-Fe2O3nanoparticles.4. Morphology had significant impact on protein adsorption behaviors of α-Fe2O3nanostructures. All the hierarchical α-Fe2O3microspheres had no ability to adsorb BSA or hemoglobin. Only α-Fe2O3nanoparticles can adsorb BSA and hemoglobin with high capacity. Zeta potential measurements indicated that adsorption mechanism can not be expalined by electrastatic interactions. Ti4+doping was another factor determining protein adsorption behaviors of α-Fe2O3nanoparticles. The doped nanoparticles only adsorbed BSA and hemoglobin under ultrasonic irradiation. Without ultrasonication assisted, Ti4+doped α-Fe2O3nanoparticles completely lost the ability to adsorb protein. On the contrary, pure α-Fe2O3nanoparticles can directly adsorb protein irrelevant to ultrasonic treatment. In addition, the protein adsorption capacity of Ti4+doped α-Fe2O3nanoparticles was much higher than that of undoped counterpart.更多还原