基于分子印迹技术与钆掺杂硅量子点的新型靶向探针的制备及其肿瘤诊疗一体化应用研究

Combining the high specificity of molecular imprinting technology and superior biological imaging properties of gadolinium doped silicon quantum dots, the targeted imaging/drug delivery probes were prepared based on the fluorescence/ magnetic resonance molecular imprinting polymers by dual template imprinting method for application in tumor diagnose and therapy. Firstly, surface functional fabrication was performed on the surface of silicon dioxide coated gadolinium doped silicon quantum dots, which was employed as the carrier. The epitopes of tumor markers and anticancer drugs were selected as imprinted template molecules which were immobilized by covalent or non-covalent force. Then, the surface imprinting was performed by methods of sol-gel, metal chelating and atom transfer radical polymerization. Finally, after eluting the templates, the targeted probe was obtained with two kinds of imprinted sites including the epitope of tumor marker and the anticancer drug. The probe could realize tumor targeted fluorescence/magnetic resonance imaging by using the fluorescence/magnetic properties of the carrier and the target recognition of tumor markers by the imprinted sites of the epitope. Meanwhile, the probe can be used for drug loading by using the imprinted sites of the anticancer drug, and the tumor position can be determined by the imprinted sites of the epitope. Via the slightly acidic environment of tumor cells, the anticancer drug could be released, which could realize the targeted treatment. This research is a frontier topic with innovativeness and significant application value, which intercross the field of nano science, polymer chemistry, analytical chemistry, clinical diagnosis and treatment, etc.

结合分子印迹技术的高特异性与钆掺杂硅量子点优越的生物成像性能，采用双模板印迹方法，制备荧光/磁共振型分子印迹聚合物靶向成像/给药探针，用于肿瘤的诊断与治疗。首先，对包硅后的钆掺杂硅量子点进行表面功能化修饰，以此为载体，选取肿瘤标志物的抗原决定基和抗癌药物同时作为印迹模板分子，通过共价或非共价方式结合上模板；然后，采用溶胶凝胶、金属螯合及原子转移自由基聚合等方法进行表面印迹；最后，洗脱模板，得到含有肿瘤标志物抗原决定基和抗癌药物两种印迹位点的靶向探针。该探针利用载体的荧光/磁性能，并借助抗原决定基的印迹位点对肿瘤标志物的靶向识别，实现肿瘤靶向荧光/磁共振成像；同时，该探针利用抗癌药物的印迹位点进行载药，借助抗原决定基印迹位点定位到肿瘤部位，肿瘤的微酸环境使药物得到释放，从而实现靶向治疗。本课题是纳米科学、高分子化学、分析化学、临床诊疗等领域相结合的前沿课题，具有创新性和显著的应用价值。

本项目基于分子印迹技术对目标分子识别的高特异性，采用双模板分子印迹技术，以肿瘤标志物的抗原决定基和抗癌药物同时作为印迹模板分子，制备了几种具有靶向功能的双模板分子印迹聚合物纳米粒子，并成功地用于肿瘤的诊断与治疗。代表性工作如下：（1）采用双模板分子印迹技术，以包硅硅量子点为载体，以肿瘤细胞表面过表达蛋白P32跨膜肽N端抗原决定基及阿霉素（DOX）为双模板分子，通过沉淀聚合法合成了荧光型双模板印迹纳米粒子（FMIPs）。DOX印迹空腔可以稳定地携带药物，而抗原决定基印迹空腔可以使FMIPs主动靶向P32蛋白表达为阳性的4T1肿瘤细胞。实验结果表明，FMIPs具有靶向荧光成像性能；负载DOX的FMIPs（FMIPs@DOX）有效地抑制了4T1恶性乳腺肿瘤的生长，从而实现了靶向治疗；（2）以硅纳米粒子作为光致发光源，修饰二氧化硅层后作为载体，以葡萄糖修饰的成纤维生长因子诱导型14（FN14）的跨膜域的71-80肽段和抗肿瘤药物博来霉素作为模板分子，通过表面印迹法，得到具有两个印迹位点的聚合物，并将其成功地用于对胰腺癌细胞BxPC-3的靶向成像和靶向治疗研究；（3）利用包覆荧光硅纳米粒子的二氧化硅微球作为载体，采用人表皮生长因子受体-2（HER2）的胞外区域的暴露肽段和DOX作为模板，通过表面印迹方法合成了荧光型的双模板分子印迹聚合物，并将其成功地用于乳腺癌细胞的靶向成像和靶向治疗；（4）以嵌有掺钆硅量子点和Ce6光敏剂的二氧化硅纳米粒子为载体，以肿瘤细胞膜表面过表达蛋白CD59的抗原决定基和DOX同时为模板分子，在载体表面以自由基聚合法制备了双模板分子印迹聚合物纳米粒子。该印迹纳米粒子具有良好的靶向成像及靶向治疗能力。该项目的研究成果可以为肿瘤的发病机理与临床诊疗研究提供强有力的技术支撑。