对于人类遗传相关疾病，基因治疗是一种新型有效的手段，而高效安全的基因递送系统是基因治疗成功的关键。阳离子聚合物和脂质体因其结构易修饰而在非病毒基因载体的发展中备受关注，但安全性和功能单一等限制了其广泛的临床应用。设计合成具有生物相容性好、功能多样性的非病毒基因载体是化学生物学研究的前沿热点。本博士学位论文在大量文献调研的基础上，针对上述问题设计合成了一系列具有生物可降解性的聚酯类分子和具有双光子（TP）聚集诱导发光（AIE）的类脂质体作为非病毒基因载体，进行了详细的基因转染和基因治疗性能研究。论文取得如下的创新成果：

1. 以戊内酯为单体，烷基链、醚氧链为侧链，大环多胺[12]aneN₃为正电单元，设计合成了具有pH响应的5个聚酯化合物，TM2-3a-TM2-3e，研究了基因转染性能并探讨了构效关系。这些聚酯均能够将DNA凝聚成纳米颗粒，在DOPE存在下，具有短侧链的聚酯TM2-3a和正电单元比例高的聚酯TM2-3d仅在N/P比为1.6时可完全阻滞DNA的移动。细胞毒性实验表明，这些聚酯相较于25kDa PEI有更好的生物相容性。TM2-3b/DOPE和TM2-3d/DOPE的转染效率优于25kDa PEI。

2. 以四苯乙烯单元为引发剂，设计合成了具有生物显像功能的3个聚酯，TM3-3a-TM3-3c，实现了聚合物在基因转染过程中的可视化。实验表明3个聚酯在与ctDNA相互作用后，荧光均有所提高。荧光素酶和绿色荧光蛋白表达实验表明，8碳侧链的聚酯TM3-3b/DOPE在HEK 293T细胞中的转染效率与25kDa PEI持平，通过共聚焦显微镜（CLSM）清晰观测到其在HeLa细胞中的转染过程，并进一步实现了其对siRNA的有效递送。

3. 以氰基乙酸修饰的四苯乙烯噻吩单元为光敏剂，不同长度的烷基链为疏水单元，大环多胺[12]aneN₃为正电单元，设计合成了具有双光子荧光显像的6个双亲性分子，TM4-1-TM4-6，实现了体外和体内的基因（GT）和光动力学（PDT）联合治疗。这些化合物在水中展示出强的AIE发射和大的Stokes位移，能够将DNA凝聚成具有恰当尺寸，带有正电性的纳米颗粒。定性和定量的转染实验说明桥连单元为12碳的载体TM4-4/DOPE在HeLa细胞中转染效率高达Lipo2000的4.5倍；在光照条件下产生足量的活性氧（ROS），TM4-4/DOPE在体内外实现了有效的GT/PDT治疗。

4. 以碱性氨基酸树枝状肽作为正电单元，设计合成了3个具有AIE效应的多功能非病毒基因载体，TM5-1-TM5-3，实现了高效的基因转染和抗癌联合治疗。目标化合物具有典型的AIE效应并且具有超低的临界胶束浓度是。实验发现全赖氨酸残基的TM5-2/DOPE在HeLa细胞中转染效率是Lipo2000的5.7倍；单、双光子荧光显像实验表明TM5-2/DOPE脂质体能被细胞快速的内吞，有效的逃离溶酶体并将DNA递送到细胞核中。TM5-2/DOPE在HeLa细胞中实现了GT和PDT联合抗癌作用。

最后，对本论文的工作进行了总结和展望。本论文从可降解聚合物和多功能脂质体两个角度设计合成了17个非病毒基因载体，研究了它们的核酸凝聚性能，细胞层面的基因转染效率，对癌细胞和肿瘤的联合治疗效果及其构效关系，为后期设计高效，低毒的非病毒基因载体提供了有益的信息。

Gene therapy is an effective strategy for treating various gene-associated diseases, and the development of gene delivery system is crucial to gene therapy. Although cationic polymers and liposomes as non-viral gene carriers have been attracted much attention due to their easy structural modification, their clinical applications are limited by their transfection efficiency (TE) and lacking of versatility. Therefore, it is important to develop high efficiency and multifunctional gene vectors. In this thesis, we rationally designed a series of non-viral gene carriers, which include biodegradable polyesters and lipidoids with two-photon imaging and aggregation-induced emission enhancement (AIE) features. The properties of these gene carriers have been systematically investigated. The major achievements of the thesis are introduced as follows:

1. Five polyesters (TM2-3a-TM2-3e) containing alkyl/alkoxy chains and positively-charged [12]aneN₃ unit were designed and synthesized as non-viral gene vectors. The TE and structure–property relationships were discussed. All of these polyesters effectively condensed DNA and formed nanoparticles via self-assembly. In the presence of DOPE, TM2-3a with shorter alkyl chains and TM2-3d with more positive charge units were able to completely retard the migration of DNA at N/P = 1.6. Cytotoxicity experiments showed that these polyesters were more biocompatibile than 25kDa PEI. Moreover, the TEs of TM2-3b with longer alkyl chains and TM2-3d were higher than that of 25kDa PEI.

2. Three polyesters (TM3-3a-TM3-3c) containing AIE-featured tetraphenylene units were designed and synthesized as non-viral gene vectors to monitor the process of gene transfection. The obtained results demonstrateded that the fluorescent intensity of the polyesters increased after interacting with ctDNA, indicating that these vectors could be used as bioimaging agents. Moreover, luciferase and green fluorescent protein expression experiments showed that the TE of TM3-3b/DOPE with 8 carbon alkyl chain was comparable with that of 25kDa PEI in HEK 293T cells. The gene delivery process of TM3-3b/DOPE was cleary investigated by confocal microscopy and achieved the effective delivery of siRNA into HeLa cells.

3. Six amphiphilic compounds (TM4-1-TM4-6) consisting of positively-charged [12]aneN₃ and photosensitizer tetraphenylethenethiophene modified cyanoacrylate linked by alkyl chain were designed and synthesized as multifunctional gene vectors to achieve the combination of gene (GT) and photodynamic (PDT) therapy in vitro and vivo. These compounds exhibited strong AIE emission and large Stokes shifts in water. These liposomes effectively condensed DNA and formed the positively charged nanoparticles with suitable sizes. The qualitative and quantitative transfection experiments showed that the TE of TM4-4/DOPE with 12 carbon alkyl chain was 4.5 times higher than that of Lipo2000 in HeLa cells. Moreover, TM4-4/DOPE was able to generate reactive oxygen species (ROS) under light irradiation, thus combination gene and photodynamic therapy was achieved in vitro and in vivo.

4. Three amphiphilic compounds (TM5-1-TM5-3) consisting of basic amino acids as positive-charged units were constructed as multifunctional non-viral vectors with AIE to achieve the combination therapy in vitro. They showed typical AIE characteristics and ultra-low critical micelle concentrations. The TE of liposome TM5-2/DOPE with lysine residues was 5.7 times that of Lipo2000 in HeLa cells. Single/two-photon fluorescence microscopy revealed that TM5-2/DOPE had rapid endocytosis, successful endo-lysosomal escape, gene release and rapid nuclear delivery. The therapeutic effect of combined gene and photodynamic therapy was successfully observed in vitro.

In the last part, the work of the thesis is summarized and the future development are proposed. Compounds including 8 polyesters and 9 multifunctional lipidoids were synthesized as non-viral gene vectors. The properties of these compounds including DNA condensation, gene transfection, anticancer activity and structure–property relationships were studied in detail. This work provides a meaningful exploration for the design of non-viral gene vectors with higher transfection efficiency and lower cytotoxicity.