基于HER2受体的长循环磁性纳米凝胶构建及“磁热疗-化疗”协同作用机制研究

Magnetic nanogel which can be used in drug delivery, tissue engineering, cancer therapy and magnetic resonance imaging has attracted much attention in scientific community. Currently, magnetic nanogel used for cancer therapy still has some shortages, such as the control of microstructure, low drug loading, fast release rate and little research about the pharmacokinetics, long-circulation and synergistic mechanism of "magnetic hyperthermia-chemotherapy". To solve the above issues, the magnetic nanogel will be firstly controlled prepared by miniemulsion polymerization from mesoscopic molecules to aggregation formation with the biodegradable cross-linker, which will realize the facile preparation and structure control of the monodispersed magnetic nanogel. The influence of interface matching on the formation and morphology of core-shell nanogel will be discussed in depth, and the formation and growth mode of magnetic nanogel will be revealed. Secondly, the cyclodextrin (CD) will be introduced in the magnetic nanogel synthesis for high-loading and controlled release of hydrophobic paclitaxel (PTX), and the release mechanism will be discussed. Finally, the herceptin will be covalently linked to the PTX-loaded magnetic nanogel surface, and the properties of dual-target and long circulating magnetic nanogel will be characterized. The best releasing conditions will be explored through the cell and mouse model experiments using the HER2 positive breast cancer as a model. The mechanism of dual-targeting magnetic nanogel system in HER2+ breast cancer “magnetic thermotherapy-chemotherapy” will be studied which can provide the theoretical basis and scientific method for the diagnosis and treatment cancer.

磁性纳米凝胶可广泛应用于药物传递、组织工程、肿瘤治疗、MRI成像等方面，近年来引起了科学界的高度关注。但目前存在微观结构较难控制、药物负载量低、释放速率过快，对药代动力学、长循环和“磁热疗-化疗”协同作用机制的研究还不够系统深入等问题。本项目采用可生物降解的交联剂，通过细乳液聚合法从介观分子到聚集态形成，实现对单分散磁性纳米凝胶的高效制备及结构控制。深入探讨界面匹配对核壳结构凝胶的形成及形态的影响规律，揭示磁性纳米凝胶壳层的形成及生长模式。并引入环糊精实现对疏水性药物紫杉醇的高效装载与控释，分析药物控释机理。在此基础上，通过化学键携载靶向HER2受体的曲妥珠单抗赫赛汀，研究双重靶向的长循环磁性纳米凝胶的制备与性能要求。以HER2阳性乳腺癌为模型，通过细胞及小鼠模型动物实验，探索最佳的给药条件，并系统研究“磁热疗-化疗”协同作用机制，为癌症的治疗提供理论基础和科学方法。

基于HER2阳性的乳腺癌分型，本项目致力于制备出生物安全性好、控释能力强、向肿瘤深部渗透能力强，同时具有“热疗-化疗协同治疗”的磁性纳米凝胶，提高HER2阳性乳腺癌的治疗效果。本项目以Fe3O4为内核、NIPAM为温度响应单体、丙烯酸AA为pH响应单体、聚（乙二醇）甲基丙烯酸酯（MAPEG）为亲水性单体，制备了pH/温度/磁性多重响应性的纳米凝胶Fe3O4@P(NIPAM-AA-MAPEG)。通过共聚的方法将环糊精（CD）引入磁性纳米凝胶，实现对疏水性药物紫杉醇PTX的装载与控释。通过调节环糊精结构、环糊精含量、药物配比来优化磁性纳米凝胶的各项性能。再通过氨羧反应键合热疗HER2靶向抗体赫赛汀，得到双重靶向的载药体系Fe3O4@P(NIPAM-AA-MAPEG-CD/PTX)@Herceptin，通过酶标仪、流式细胞仪、蛋白印迹、激光共聚焦显微镜、细胞透射电镜研究磁性纳米凝胶对MCF-7肿瘤细胞的抑制效果。在MCF-7肿瘤诱导的小鼠中评价了体内抗肿瘤效果，结果表明，磁性纳米凝胶对HER 2阳性乳腺癌治疗非常有效。MNLs在生理环境中表现出优越的稳定性，但在酸性环境中其结构被破坏，加速了PTX的释放。HER-PTX-MNLs的解离加速了PTX的递送，并增强了治疗效果。研究表明，HER-PTX-MNLs可以抑制肿瘤的生长。此外，高磁含量的磁性纳米凝胶在乳腺癌诊断的磁共振成像（MRI）方面具有潜在的优势。最后，将磁性纳米凝胶与多巴胺颗粒结合，实现乳腺癌热疗-化疗的功能，探讨磁性纳米凝胶“热疗-化疗”的协同机制。总之，我们进一步改进了磁性纳米凝胶的性能，扩充了其功能，并为改善药物载体控释技术提供了新方法，也为乳腺癌治疗效果提供了理论和实践基础。同时，在本项目的支持下，项目负责人主要发表SCI论文5篇，参与项目的团队成员发表5篇SCI论文，获得1项江苏省科学技术三等奖，1项江苏省复合材料学会青年科技奖，申请并授权国家发明专利5项，培养硕士生1名，本科生1名，毕业2人。