可视化前药系统用于基因化疗药物共载及精准诊疗的研究

This project aims to explore three major problems in gene & drug co-delivery system, including interference between the two cargos, low drug loading efficiency and poor in vivo tracing. .We will design and construct a visible prodrug nanoparticles as gene vector, with cationic penetrating peptides as the hydrophilic part, disulfide bonds containing near infrared (NIR) cyanine molecules as the linker, and prodrugs as the hydrophobic segment. After self-assembly, positively charged component could compress gene and compact with hyaluronic acid to form a gene complex. The fabricated complex does not show fluorescence due to the aggregation fluorescence quenching effect. .During delivery process, the complex could target to the tumor site, due to hyaluronic acid in the outer layer and EPR effect. After entering cell, the disulfide bonds will break, leading to the disintegration of the carriers. And then the cargos of gene and prodrug will be released. Meanwhile, the fluorescent molecules will disperse and re-lighten. The released siRNA can downregulate target protein earlier and faster. After the gene is fully functionalized, the prodrug will degrade by enzyme to recover its activity, and then exerts its effect later. Therefore, the genes and drugs loaded in the nano-system are released in sequence, in order to achieve the best combination of the co-loaded therapeutic molecules. .The NIR-fluorescent molecules in the system could also promote gene transfection and tumor killing by using the photo dynamic and photo thermal effects/therapy..Through the comprehensive investigation of the system, the structure effect relationship of the carrier and the therapeutic effect of tumor in vivo and in vivo can be studied.

本项目拟将针对基因、药物共输送系统中相互干扰、载药量低及体内示踪困难三大问题，设计构建一种可视化的前药基因载体：穿膜性能的阳离子肽为亲水部分，含二硫键的近红外菁类分子作为连接部分，前药为疏水部分。各组分自组装后带正电，能压缩基因，并与透明质酸混合形成基因复合物，该复合物因聚集荧光淬灭效应不发光。外层的透明质酸和EPR效应会将复合物靶向到肿瘤部位，进入细胞后，二硫键断裂、载体崩解，释放出基因和前药，同时荧光分子因散开而重新发光。随后siRNA下调目标蛋白。其充分作用后，前药也在肿瘤特定的酶环境下降解成活性药物，再发挥功效。因此，纳米体系所装载的基因和药物依次顺序释放起效，使共载的治疗分子达到最佳的组合作用。还能利用荧光分子的光动和光热效应，协助基因转染、杀伤肿瘤细胞。通过对该系统的全面考察，可对载体的构效关系、体内外肿瘤治疗效果进行研究。

本项目针对基因、药物共输送系统中相互干扰、载药量低及体内示踪困难三大问题，探索性的设计构建2种可视化的前药基因载体：穿膜性能的阳离子肽为亲水部分，含二硫键的近红外菁类分子作为连接部分，前药为疏水部分。各组分自组装后带正电，能压缩基因，并与透明质酸混合形成基因复合物，该复合物因聚集荧光淬灭效应不发光。外层的透明质酸和EPR效应会将复合物靶向到肿瘤部位，进入细胞后，二硫键断裂、载体崩解，释放出基因和前药，同时荧光分子因散开而重新发光。随后siRNA下调目标蛋白。其充分作用后，前药也在肿瘤特定的酶环境下降解成活性药物，再发挥功效。纳米体系所装载的基因和药物依次顺序释放起效，使共载的治疗分子达到最佳的组合作用。还能利用荧光分子的光动和光热效应，协助基因转染、杀伤肿瘤细胞。通过对该系统的全面考察，可对载体的构效关系、体内外肿瘤治疗效果进行研究。执行期间，完成15篇SCI论文（包括Advanced Drug Delivery Review, Small, Acta Pharmaceutica Sinica B, Nanoscale, Materials and Design等），获批2项省市级项目，10项中国发明专利和培养8名硕/博士研究生（3名已毕业博士，3名已毕业硕士，2名在读硕/博士），通过项目的执行，深入揭示影响基因-前药输送系统体内外输送的因素及作用规律，进一步为肿瘤精确诊治的纳米输送系统的设计、构建提供新的思路和方法。