光控智能DNA纳米水凝胶设计及其在miRNA的精准输送和释放方面的应用

MicroRNA (miRNA) is an important member of the non-coding RNA family. The abnormal expression of miRNA is closely related to the occurrence, development, metastasis and drug resistance of many malignant tumors. Therefore, if real-time, dynamic and precise regulation of miRNA function can be achieved in cancer cells on the time axis, it may have an important guiding significance for us to further understand the mechanism of miRNA and design an effective nano-carrier for miRNA/drug co-delivery. In this project, the photo-responsive dye molecule modified DNA was introduced into the drug carrier to design a photoregulated smart DNA nanohydrogel for the precise delivery and release of miRNA. The nanohydrogels possess active targeting function, which can be transfected into specific cancer cells through receptor recognition, and then release of miRNA under photoirradiation. The effect of regulation action on cell cycle, apoptosis and drug resistance will be investigated at different time periods to obtain information that previous studies could not get. On this basis, this project will also attempt to enhance the chemotherapy efficacy by using drug resistant MCF-7/doxorubicin cancer cell lines. The photoregulated smart DNA nano-hydrogel developed in this project has a profound theoretical guidance for the innovative research in the field of biomedical materials.

作为非编码RNA家族中的重要成员，miRNA的异常表达与诸多恶性肿瘤的发生发展、转移、及耐药性等密切相关。因此，如果能在时间轴上实现对癌细胞中miRNA功能的实时动态精准调控，对我们深入理解miRNA的作用机制，设计高效的miRNA/药物纳米载体具有重要的指导意义。本项目将光响应性染料分子修饰DNA引入到药物载体中，设计一种光控智能DNA纳米水凝胶用于miRNA的精准输送和释放。该纳米水凝胶具有主动靶向功能，可通过受体识别被转染至特定的癌细胞内，并在光照下释放miRNA。我们将考察在不同时间段的调节行为对细胞周期、细胞凋亡及耐药性的影响，获得以往研究不能得到的信息。在此基础上，本项目也将进行改善乳腺癌耐药细胞株MCF-7/阿霉素耐药性的研究。本项目开发的光控智能DNA纳米水凝胶对于生物医用材料领域的创新研究有着深刻的理论指导价值。

MicroRNA (miRNA)的异常表达与诸多恶性肿瘤的发生发展、转移、及耐药性等密切相关。因此，如果能实现对癌细胞中miRNA表达水平的时空调节，对我们深入理解miRNA的作用机制，设计高效的miRNA/药物纳米载体具有重要的指导意义。本项目在前期研究工作的基础上，开发了核酸适配体功能化DNA纳米水凝胶和核酸适配体-miRNA抑制剂共价偶联型DNA纳米水凝胶，并通过载药和释药、癌细胞转染及细胞毒性实验，建立了基于DNA纳米水凝胶的药物及药物/miRNA抑制剂共递送实验评价体系。设计制备了光响应性miR-21抑制剂，并在体外验证了光控释放效果。通过对miR-21抑制剂的负载方式的系统考察，设计制备了包载光响应性miR-21抑制剂的还原敏感型磁性纳米水凝胶，并将其输送至癌细胞中，确认了miR-21抑制剂的光控释放效果。但由于细胞表面及其内部成分的高度复杂性等原因，细胞内光控释放效果不及体外理想，有待进一步探索。本项目研究为细胞内生物大分子的结构和功能的可逆光控调节研究积累了宝贵的经验，研究过程中所开发的纳米水凝胶和核酸的化学修饰方法应用于靶向抗肿瘤药物递送、细胞成像和DNA分子探针研究并发表SCI论文5篇，申请国内发明专利2项，获专利授权3项。