具有yolk-shell 结构和垂直孔道的磁性介孔微球材料的设计合成及应用研究

Ordered mesoporous materials have shown great potential for application in catalysis, drug delivery, and sensor due to their high surface area and large pore volume. In the other side, owing to their unique magnetic properties, magnetic nanomaterials exhibit magnetic separability under permanent magnetic field which is favorable for application as separable carriers; they also display localized heat-generating phenomenon under alternating magnetic field due to the Néel relaxation, which has been applied in hyperthermia. Magnetic mesoporous mateirals, combining the advantages of both mesoporous materials and magnetic nanomateirals,have attracted considerable interest from interdisplinary communities spaning chemistry, materials sciences and biomedicine. Unfortunately, the reported magnetic mesoporous mateirals have irregularly alligned pores, small pore volume, low-magnetization, and/or ill-defined structure, which affects their applications. This project will develop novel yolk-shell structured magnetic microspheres with carbon-coated magnetic core, hollow interior and mesoporous silica shell through a well-design approach combining the sol-gel chemistry, templating synthesis, and interface assembly technique. The designed yolk-shell microspheres will be synthesized by successively depositing a layer of amorphous carbon, non-porous silica layer and mesostructure silica/surfactant shell on magnetite particles, followed with selective removal of nonporous silica and extraction of surfactants. The hollow structure and the mesopores perpendicular to the spheres'surface will be used as the pool for anti-cancer, while mesopores serve as the channel for guest molecules to come in and out. The drug molecules will be loaded in the hollow space of the yolk-shell microspheres to investigate the drug release behavior under alternating magnetic field by using the Néel relaxation of magnetic core, aiming to develop a novel smart drug delivery system for disease like cancer.

有序介孔材料由于其比表面积高、孔体积大等特点在催化、药物输送、传感等领域显示了巨大的应用前景。另一方面，磁性纳米材料不仅具有易磁分离的特点，而且还能在外加交变磁场中显示生热现象（尼尔弛豫效应）并用于超高热治疗。磁性介孔复合材料由于结合了二者的优势，吸引了化学、材料科学、生物医学等多学科的研究兴趣，目前报道的磁性介孔材料具有孔道不规则、孔体积小、磁性弱、结构不可控等不足，影响了其实际应用。本课题拟结合溶胶-凝胶法、模板合成以及界面组装法，通过在磁性颗粒表面依次可控沉积无定形碳、无孔SiO2和有序介观结构的表面活性剂/SiO2复合外壳，通过选择性去除无孔SiO2中间层以及外壳中的模板剂，合成一种具有磁性内核、中间空腔、垂直孔介孔外壳的yolk-shell微球材料。拟利用其巨大的空腔负载抗肿瘤药物，利用磁性组分在交变磁场下产生的局域化升温实现药物遥控释放，为肿瘤等疾病的治疗提供新型智能药物系统。

磁性yolk-shell 介孔微球材料由于其兼具了磁性材料的磁学性能和介孔空心球材料高比表面积、良好的孔道连通性以及巨大的腔体，因而它们在催化、分离、富集以及纳米药物等方面具有广阔的应用前景。本项目结合界面组装、超分子模板合成、牺牲性高分子模板作用、液滴模板等策略设计合成了一系列磁性yolk-shell的磁性介孔空心微球，阐述了材料合成机理并开展了它们在限域催化烯烃环氧化等方面的应用研究，相关研究结果发表JACS、 Chem. Mater. 等期刊，共计36篇SCI论文，同时申请了6件中国发明专利，授权3件。该项目研究成果为开发磁性yolk-shell介孔微球奠定了较好的研究基础。