胆固醇型阳离子脂质体介导基因转运研究进展

胆固醇是许多天然生物膜的重要成分,嵌入阳离子脂质体用于基因转运,具有转染效率高、降低细胞毒性、制备简单等优点,在介导基因转运方面具有广阔的应用前景。在近年来胆固醇嵌入阳离子脂质体研究的基础上,论述了胆固醇在阳离子脂质体中的作用方式及其介导基因转运方面的研究现状,展望了胆固醇嵌入式阳离子脂质体的发展方向。     

DOPE嵌入式阳离子脂质体介导基因转运研究

二油酰磷脂酰乙醇胺(DOPE)是应用最广泛的中性磷脂,作为非病毒基因载体的重要组成部分,具有很强的细胞膜去稳定化作用,克服了阳离子脂质体高细胞毒性、制备困难、缺乏稳定性等缺点,在介导基因转运方面具有广阔的应用前景。在近年来DOPE嵌入阳离子脂质体介导基因转运研究的基础上,论述了DOPE嵌入阳离子脂质体的作用方式和在介导基因转运方面的研究现状,并展望了DOPE嵌入式阳离子脂质体的发展方向。     

核-壳型脂质体基因载体的研究进展

脂质体作为一种重要的非病毒基因载体,在核酸和药物转运方面有着巨大的优势和潜力。近年来脂质体基因载体的研究基础上,主要介绍了脂质体-聚阳离子-DNA复合载体(LPD)和脂质体-磷酸钙纳米粒子复合载体(LCP)两种核-壳型脂质体基因载体,展望了核-壳型脂质体基因载体的发展方向及其在基因治疗领域的应用前景。     

阳离子脂质体基因转染研究

目的：评价阳离子脂质体介导基因转染宫颈癌细胞的转染效果,优化对宫颈癌细胞的转染条件。方法：以荧光素酶基因pGL3为报告基因,分析影响阳离子脂质体Lipofectamine 2000转染Hela效率的因素。结果：通过细胞转染实验,得出脂质体与pDNA的稀释液混合较佳等待时间为30 min,脂质体/pDNA复合物与细胞接触的转染时间为4 h,转染效率较高。结论：Lipofectamine2000 Hela细胞转染效率较高。     

不同端基肽头部阳离子类脂基因转运研究

阳离子端基肽类脂作为一种重要的非病毒基因载体,在基因转运方面具有广阔的应用前景。类脂结构是转染效率的主要因素,亲水头部起着脂质体与DNA、脂质体-DNA复合物与细胞膜或与细胞内其他组分相互结合的作用。基因表达效率与阳离子类脂的端基肽头部有关。而且,类脂的毒性也受到端基肽头部的影响。在近年来阳离子端基肽类脂的研究基础上,从阳离子端基肽类脂头部的构建进行了论述,概述了端基肽头部的种类及其基因转运效率,展望了阳离子端基肽类脂的发展方向。     

用于基因转染的阳离子脂质体研究进展

开发高效、低毒、具有靶向性的基因载体是基因治疗的关键。阳离子脂质体因具有低毒性与免疫原性、生物相容性好、易于制备等优点而受到广泛关注,具有良好的应用前景。近年来,人们通过使用各种辅助性成分研发新型材料,对脂质材料进行表面修饰以及制备工艺调整等方法改进阳离子脂质体的性能。从上述几方面综述了此类基因传递载体的研究进展。     

阳离子脂质体DLin-MC3-DMA合成

可电离的阳离子脂质体DLin-MC3-DMA是一种高效的siRNA运输载体,它能有效封装相应的siRNA并使其进入细胞质内,然后两者分离,siRNA发挥其功效。以价格低廉的亚油酸为起始原料,经还原、溴代、格氏和缩合等4步反应,高效合成了目标化合物DLin-MC3-DMA,不仅缩短了反应步骤,而且有效降低了成本。     

阳离子高分子化合物作为基因载体的研究进展

近年来,非病毒基因治疗载体备受关注。主要介绍了作为非病毒基因载体材料的阳离子高分子化合物及其研究进展,包括阳离子脂质体及阳离子聚合物(聚乙烯亚胺、聚赖氨酸、壳聚糖、环糊精)。     

氨基酸类阳离子脂质体在基因转染中的应用

通过化工程序合成阳离子脂质TMA-C2-Glu-C12,经双蒸水超声分散后制得相应的氨基酸类阳离子脂质体,实验共合成了八种氨基酸类阳离子脂质,经过二次整流后分散成对应的质体。实验结果表明,在HBL100、HT1080和GC-1细胞系中,TMA-C2-Glu-C12的转染效率与Lipofectamine 2000相当,在HEK293、Ges-1、Huvce、HeLa和SW480细胞系中进行结果对比,实验表明TMA-C2-Glu-C12的细胞毒性不强,是一种高效的基因转载体。     

双氨基甲酸酯键连接的阳离子类脂前体合成

随着生物化学与分子生物学理论的不断发展,基因治疗已成为医学界最活跃的研究领域之一。基因治疗载体在基因治疗过程中起一个转运和保护的作用,是基因治疗成功与否的关键。因此,基因治疗载体的开发对基因治疗的发展尤为重要,其有效开发将推动基因治疗向常规治疗方法的转变。目前,用于临床的基因载体大致分为病毒载体和非病毒载体两类,它们都具有各自鲜明的优缺点,在临床治疗上亟需改进目。脂质体在所有已用于临床试验的基因载体中仅次于病毒载体,居第二位,是最有发展前景的非病毒载体。其中。阳离子脂质体由于具有对阴离子型聚电解质敏感。对带负电荷的DNA有较高的转运能力．还能转运RNA、核糖体及其他大电荷的分子和大分子物质进入细胞等优点,其转染效率比其他脂质体高出许多倍。因而被广泛应用于基因转移技术中。在阳离子类脂的结构中。连接键是一个非常重要的组成部分。它直接决定了阳离子脂质体的化学稳定性及被生物降解的能力,进而影响阳离子类脂的转染效率和细胞毒性141。现在已合成出来的用于基因治疗的阳离子脂质体的连接键主要有醚键（如DOTMA、DMR．IE）IS．-91和酯键（如DOTAP）两种。前者由于过于稳定,在完成转染任务后不易分解。遗留在细胞内部对细胞产生毒害;而后者由于不够稳定,在转染过程中就易分解,对细胞的转染效率产生不利影响。 因此．本课题组设计了以氨基甲酸酯键作为连接键的阳离子类脂．通过改变类脂前体分子中碳链长度、类脂分子合成中卤代烷碳链长度和卤素的类型来得到一系列的阳离子类脂,计划利用其pH敏感性和细胞内外的pH值差别,使在细胞外稳定的阳离子类脂在进入细胞内完成转染任务后可以分解成小分子有机物顺利排出,从而达到较好的转染效率和较低的细胞毒性旧。     

脂质体协同磷酸钙/DNA共沉淀的基因转染研究

利用商业化的脂质体Lipofectamine 2000协同高Ca/P值的Ca-P/DNA共沉淀提高基因转染效率,并保持了其较低的细胞毒性。结果表明,当Ca/P值为150时,加入0.2μL脂质体Lipofectamine 2000可得到高基因转染效率和低细胞毒性。这种脂质体协同Ca-P/DNA共沉淀技术有望在基因治疗中得到广泛应用。     

Biodegradable Tri-Block Copolymer Poly(lactic acid)-poly(ethylene glycol)-poly(l-lysine)(PLA-PEG-PLL) as a Non-Viral Vector to Enhance Gene Transfection

Low cytotoxicity and high gene transfection efficiency are critical issues in designing current non-viral gene delivery vectors. The purpose of the present work was to synthesize the novel biodegradable poly (lactic acid)-poly(ethylene glycol)-poly(l-lysine) (PLA-PEG-PLL) copolymer, and explore its applicability and feasibility as a non-viral vector for gene transport. PLA-PEG-PLL was obtained by the ring-opening polymerization of Lys(Z)-NCA onto amine-terminated NH₂-PEG-PLA, then acidolysis to remove benzyloxycarbonyl. The tri-block copolymer PLA-PEG-PLL combined the characters of cationic polymer PLL, PLA and PEG: the self-assembled nanoparticles (NPs) possessed a PEG loop structure to increase the stability, hydrophobic PLA segments as the core, and the primary ɛ-amine groups of lysine in PLL to electrostatically interact with negatively charged phosphate groups of DNA to deposit with the PLA core. The physicochemical properties (morphology, particle size and surface charge) and the biological properties (protection from nuclease degradation, plasma stability, in vitro cytotoxicity, and in vitro transfection ability in HeLa and HepG2 cells) of the gene-loaded PLA-PEG-PLL nanoparticles (PLA-PEG-PLL NPs) were evaluated, respectively. Agarose gel electrophoresis assay confirmed that the PLA-PEG-PLL NPs could condense DNA thoroughly and protect DNA from nuclease degradation. Initial experiments showed that PLA-PEG-PLL NPs/DNA complexes exhibited almost no toxicity and higher gene expression (up to 21.64% in HepG2 cells and 31.63% in HeLa cells) than PEI/DNA complexes (14.01% and 24.22%). These results revealed that the biodegradable tri-block copolymer PLA-PEG-PLL might be a very attractive candidate as a non-viral vector and might alleviate the drawbacks of the conventional cationic vectors/DNA complexes for gene delivery in vivo.     

Efficient Delivery of Plasmid DNA Using Cholesterol-Based Cationic Lipids Containing Polyamines and Ether Linkages

Cationic liposomes are broadly used as non-viral vectors to deliver genetic materials that can be used to treat various diseases including cancer. To circumvent problems associated with cationic liposome-mediated delivery systems such as low transfection efficiency and serum-induced inhibition, cholesterol-based cationic lipids have been synthesized that resist the effects of serum. The introduction of an ether-type linkage and extension of the aminopropyl head group on the cholesterol backbone increased the transfection efficiency and DNA binding affinity compared to a carbamoyl-type linkage and a mono aminopropyl head group, respectively. Under optimal conditions, each liposome formulation showed higher transfection efficiency in AGS and Huh-7 cells than commercially available cationic liposomes, particularly in the presence of serum. The following molecular structures were found to have a positive effect on transfection properties: (i) extended aminopropyl head groups for a strong binding affinity to plasmid DNA; (ii) an ether linkage that favors electrostatic binding to plasmid DNA; and (iii) a cholesterol backbone for serum resistance.     

光致阳离子聚合引发剂的进展

光致阳离子聚合体系具有聚合速度快、不受氧干扰以及对水不敏感等优点,为了适应光致阳离子聚合体系的发展,可进行光致阳离子聚合的单体和光致阳离子引发剂的研究越来越受到人们的重视,本文就其中的一方面光致阳离子引发剂的种类、制备以及引发机理进行了综述。     

阳离子光引发剂研究进展

阳离子型光引发剂是一类新型的紫外光固化材料的引发剂。本文介绍了阳离子光引发剂的主要种类及各自的特点 ,讨论了其光引发机理 ,并简述了阳离子光引发剂的的发展概况和主要用途。     

Novel Cholesterol-Based Cationic Lipids as Transfecting Agents of DNA for Efficient Gene Delivery

The design, synthesis and biological evaluation of the cationic lipid gene delivery vectors based on cholesterol and natural amino acids lysine or histidine are described. Cationic liposomes composed of the newly synthesized cationic lipids 1a or 1b and neutral lipid DOPE (1,2-dioleoyl-l-α-glycero-3-phosphatidyl-ethanolamine) exhibited good transfection efficiency. pEGFP-N₁ plasmid DNA was transferred into 293T cells by cationic liposomes formed from cationic lipids 1a and 1b, and the transfection activity of the cationic lipids was superior (1a) or parallel (1b) to that of the commercially available 3β-[N-(N'',N''-dimethylaminoethyl)-carbamoyl] cholesterol (DC-Chol) derived from the same cholesterol backbone with different head groups. Combined with the results of agarose gel electrophoresis, transfection experiments with various molar ratios of the cationic lipids and DOPE and N/P (+/−) molar charge ratios, a more effective formulation was formed, which could lead to relatively high transfection efficiency. Cationic lipid 1a represents a potential agent for the liposome used in gene delivery due to low cytotoxicity and impressive gene transfection activity.     

紫外阳离子光引发剂及其发展动态

阳离子型光引发聚合是一种快速、高效、低能耗和低污染的聚合方式。着重介绍阳离子光引发剂的主要种类、各自的特点及其光引发机理,简述阳离子光引发剂在涂料中的应用和发展,并对今后的研究方向进行了展望。     

聚甲基丙烯酸N,N-二甲氨基乙酯及其衍生物作为非病毒基因载体的研究进展

综述了聚甲基丙烯酸N,N-二甲氨基乙酯(PDMAEMA)及其衍生物作为非病毒基因载体的研究进展,包括PDMAEMA及其衍生物相对分子质量及结构与转染效率之间的关系、亲水性聚合物修饰的PDMAEMA和低相对分子质量的PDMAEMA接枝共聚物,并展望了PDMAEMA及其衍生物作为非病毒基因载体的发展方向。     

多肽尿素生产技术与发展前景

多肽尿素具有提高尿素利用率、改良土壤、增加产量、改善品质、智能缓释、促早熟以及增强作物抗旱、抗寒、抗病等独特功效。概述了多肽尿素的制取原理及生产技术,分析了多肽尿素的市场与效益,展望了多肽尿素在农业领域的发展前景。