癌细胞标志物靶向性羟基磷灰石纳米药物的构建与应用

Nanotheranostics platform, can realize one or more of the treatments combination and tumor site imaging, real-time and accurate diagnosis and treatment simultaneously, monitor the curative effect in the process of treatment and adjust dosage regimen, which is conducive to achieve the best treatment effect and reduce side effects. In the pre-project, based on the characteristics of high biocompatibility, easy acidolysis in weak acid conditions and non-toxic product, nanometer hydroxyapatite (HAP) materials were prepared combined with co-precipitation and hydrothermal synthesis method, resulting in its intake and drug release in the normal tissue was reduced greatly. The project is proposed on the basis of original work, to build active targeting cancer cells HAP nanoparticle drug delivery system with high selectivity, rapid positioning and sustained release, according to optimize the synthetic solution, further reduce the HAP drug-loading nanoparticles size, increase the rate of drug loading and dispersion, and modify probes with cancer markers fluorescent response and nuclear magnetic resonance response integration on its surface. From the aspects of in vitro, cancer cells, and even mice tumors, research the drug release process, the distribution of nanoparticles uptake in live mice and pharmacokinetic, etc., providing more detailed parameters for the treatment of cancer. The completion of the project is of great significance to the diagnosis and treatment of cancer.

诊疗一体化纳米平台，可实现一种或多种治疗方法与肿瘤部位成像的结合，实时、精确诊断病情并同步进行治疗，而且在治疗过程中能够监控疗效并随时调整给药方案，有利于达到最佳治疗效果，减少毒副作用。本项目前期工作中，基于纳米羟基磷灰石（HAP）材料的高生物相容性，弱酸性下易酸解、且酸解产物安全无毒等特点，结合共沉淀和水热合成法制备的载药HAP纳米粒子，在正常组织中的摄取和药物释放大大降低。本项目拟在原创工作基础上，优化合成方案，进一步降低HAP载药纳米粒子的粒径、提高药物负载率和分散度，并在其表面修饰癌细胞标志物荧光响应和磁共振响应一体化探针分子，构建主动靶向癌细胞的高选择性、快速定位、药物缓释的HAP纳米药物输送体系。从体外、细胞乃至小鼠肿瘤层面，研究药物释放历程，以及小鼠活体中的纳米粒子摄取分布及药代动力学等，为癌症提供更为详尽的治疗参数。项目完成对癌症诊疗具有重要意义。

靶向纳米药物由于其靶向能力强、毒副作用低等优点，被广泛的发展并应用于肿瘤治疗。羟基磷灰石（HAP）是人体牙齿的主要成分，具有优良的生物相容性、生物安全性和酸性响应的特点。因此，本课题采用HAP作为纳米载体，设计制备载药HAP纳米材料用于靶向肿瘤治疗。通过调控HAP纳米材料合成过程的条件及参数，制备DOX@HAP。进一步分别采用GGT酶荧光染料、多肽cRGD和透明质酸三种靶向肿瘤标志物的分子对DOX@HAP纳米材料进行表面修饰，构建3种靶向肿瘤的纳米药物。其中，GGT酶表面修饰的DDHAP可对GGT酶过表达肿瘤细胞实现靶向，并酸解释放负载药物DOX，提高了载药纳米材料在正常/肿瘤细胞及组织中的选择能力，降低了对正常组织细胞的毒副作用，改善了纳米材料在体内的药物分布，提高了纳米材料的肿瘤治疗效果。cRDHAP对整合素αvβ3过表达肿瘤细胞的靶向能力强，纳米材料引入核酸染料Na-RNA有效的提高了负载药物DOX的利用率。SiO2/HAP复合纳米材料大大提高了载药率，载药量达到37.21%；同时，复合纳米材料具有对肿瘤微酸性环境响应的能力，摄取后可实现纳米材料的酸性降解，快速释放负载药物，克服了二氧化硅纳米材料难降解的缺点。此外，研究发现,低分子量透明质酸（oHA）具有更好的CD44过表达肿瘤细胞靶向能力和药物释放效率。本项目还采用高度共轭的七甲川菁染料为碳源，以PEG600为表面钝化剂，制备并分离得到发射波长为710 nm的近红外荧光碳点（CDs），该CDs与革兰氏阳性菌结合荧光增强，与革兰氏阴性菌结合荧光猝灭，从而区分细菌种类及评估细菌生存状态；以多巴胺为表面钝化剂，制备并分离得到发射波长为935 nm的近红外II区荧光CDs，该CDs表面带正电荷，能够快速鉴别出耐药性细菌。并使得NIR-II CDs作为荧光探针进行NIR II活体成像成为可能，实时监测小鼠免疫系统与体内感染细菌的相互作用情况，对于及时使用抗生素具有一定的指导作用。