PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的制备壳聚糖纳米粒并构建聚乙二醇（PEG）化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性。方法采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒（报告基因）;对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝（MTT）法测定壳聚糖纳米粒对细胞的毒性作用。结果喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26％,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63．4％。结论对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用。     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

超声及超声微泡联合shRNA质粒对survivin基因的沉默效应

目的:研究超声及超声微泡联合短发夹状RNA(shRNA)干扰技术对宫颈癌细胞(Hela)survivin基因的沉默效应.方法:构建3个靶向survivin基因的shRNA真核表达质粒(pSIREN/S1/S2/S3)和无关序列质粒(pSIREN/con),对培养的Hela细胞行超声及超声微泡联合处理(US+SO)或脂质体转染,以空白细胞组、单纯超声辐照组、pSIREN/S1组、超声辐照+pSIREN/S1组为对照,应用蛋白质印迹和RT-PCR检测survivin蛋白表达及mRNA转录水平的变化.结果:酶切、测序分析证实重组质粒构建成功.RT-PCR和蛋白质印迹法表明,3种pSIREN/S均可抑制Hela细胞内survivin mRNA和蛋白质的表达(P＜0.05),而pSIREN/con无此作用,以pSIREN/S3的抑制效果最显著(P＜0.05);US+SO组的mRNA和蛋白表达水平的抑制率分别为(87.04±1.80)%和(85.94±1.02)%,均显著高于其他各组(P＜0.05).结论:survivin可将作为宫颈癌基因治疗的理想靶标,超声及超声微泡联合shRNA干扰技术可显著沉默靶基因survivin的表达.     

含B7-H1 shRNA基因的慢病毒表达载体的制备及其抑制效果鉴定

目的 设计针对B7-H1的shRNA序列,构建慢病毒表达载体,包装成病毒颗粒后检测其对U251细胞中B7-H1基因的沉默效果.方法 设计3对针对B7-H1 mRNA的shRNA,化学合成正义链和反义链,退火后与酶切后的pLKO.1载体进行连接.测序正确后包装成病毒并感染U251细胞,分别用qRT-PCR及Western blot法检测干扰效果.结果 qRT-PCR及Western blot结果证实设计的3条RNA干扰序列中有2条可有效沉默U251细胞中B7-H1的表达.结论 所制备的针对B7-H1的shRNA慢病毒能特异性沉默B7-H1.     

Size-dependent transfection efficiency of PEI-coated gold nanoparticles

Gold nanoparticles (Au NPs) are promising vectors for gene delivery applications. In order to gain insight on the influence of particle size on cell transfection, Au NPs were combined with poly(ethylenimine) (PEI) to prepare two sets of PEI-coated Au NPs having particle-size distributions centered at about 6 nm (<10 nm Au-PEI NPs) or 70 nm (<100 nm Au-PEI NPs), respectively. Au-PEI NPs were coupled to a variety of plasmids carrying reporter or suicide genes to prepare Au-PEI NPs/DNA complexes, and human osteosarcoma Saos-2 cells were used to investigate the performance of the Au-PEI NPs as transfection vectors in serum-containing media. The conjugates of DNA with both types of Au-PEI NPs were found to be negatively charged. In spite of the electrostatic repulsion that occurs between the surface of the cell and the surface of the plasmid-conjugated NPs, cell internalization was observed for both kinds of Au-PEI NPs. Cells were efficiently transfected with complexes derived from <10 nm Au-PEI NPs, but not with the <100 nm Au-PEI NPs. Large aggregates of NPs associated with DNA were found in endocytic vesicles of cells incubated with <100 nm Au-PEI NPs, while the success of the smaller Au-PEI NPs as transfection vectors was related to their lower agglomeration state inside cells and to endosomal escape of DNA.     

Effect of GPE-AGT nanoparticle shRNA transfection system mediated RNAi on early atherosclerotic lesion

Objective

To investigate the effects of RNA interference targeting AGT on early atherosclerotic lesion in the hypertensive state.

Methods

Hypertension and atherosclerosis rats were treated with GPE nanoparticles carrying AGT shRNA. Systolic blood pressure and heart rate were measured for 2 consecutive weeks. Three days after treatment, the mRNA and protein expressions of AGT in the liver were measured by PCR and western blot assay, respectively. The blood levels of AGT and Ang II were determined by ELISA. H&E staining and electron microscopy were performed.

Results

Three days after AGT shRNA treatment, the mRNA and protein expressions of AGT in the liver were markedly reduced and the blood levels of AGT and Ang II dramatically decreased as compared to the remaining 3 groups (P < 0.05). Three days after AGT shRNA treatment, the blood pressure was reduced by 27 ± 4mmHg when compared with that at baseline (P < 0.05). About 11 days after AGT shRNA treatment, the blood pressure began to increase. The blood pressure remained unchanged in the remaining 3 groups. Microscopy showed the atherosclerotic lesions were markedly attenuated in AGT shRNA treated rats but the liver and kidney functions remained stable (P > 0.05) when compared with the remaining 3 groups.

Conclusion

Transfection with GPE nanoparticle carrying AGT shRNA can stably lower the blood pressure and improve the atherosclerotic lesions which lead to the delayed development of early atherosclerotic lesions in hypertension rats with concomitant atherosclerosis.     

Marked transfection enhancement by the DPL (DNA/peptide/lipid) complex

A short peptide, corresponding to the nuclear localization signal of the human immunodeficiency virus-1 Tat protein, Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg, was modified by adding a cysteine residue at the COOH terminus. The peptide was mixed with a reporter plasmid, and then with cationic lipids, to form a tripartite complex, DNA/peptide/lipid (DPL). Various cell lines were treated with the DPL complex and compared for transfection efficiency with those of the conventional DNA/lipid (DL) complex. With the simple inclusion of the peptide, the DPL complex showed much enhanced transfection. Meanwhile, the plasmid DNA mixed only with the peptide exhibited some improvement but with much lower transfection than the DPL complex. When the DPL complex was formed with various cationic lipids, the DOSPA/DOPE exhibited superior transfection efficiency than the other cationic lipids tested at the optimal ratio of 1:3:5 (w:w:w) in many cell types. At the optimal ratio of the DPL components, transfection efficiency was routinely shown to be approximately 10-fold higher for reporter gene expression than that of the conventional DL complex. Furthermore, when subcutaneous tumors of a colon cancer cell line (SW480) were treated intratumorally with antisense oligos, k-ras-RiAS, delivered as a DPL complex, tumor growth was markedly suppressed. This study shows that the DPL complex, which is easy to formulate by ordered mixing, can be employed for a much enhanced cellular uptake of a transgene both in vitro and in vivo.     

The effect of environmental pH on polymeric transfection efficiency

Although polymers, polyplexes, and cells are exposed to various extracellular and intracellular pH environments during polyplex preparation and polymeric transfection, the impact of environmental pH on polymeric transfection has not yet been investigated. This study aims to understand the influence of environmental pH on polymeric transfection by modulating the pH of the transfection medium or the culture medium. Changes in the extracellular pH affected polymeric transfection by way of complex factors such as pH-induced changes in polymer characteristics (e.g., proton buffering capacity and ionization), polyplex characteristics (e.g., size, surface charge, and decomplexation), and cellular characteristics (e.g., cellular uptake, cell cycle phases, and intracellular pH environment). Notably, acidic medium delayed endocytosis, endosomal acidification, cytosolic release, and decomplexation of polyplexes, thereby negatively affecting gene expression. However, acidic medium inhibited mitosis and reduced dilution of gene expression, resulting in increased transfection efficiency. Compared to pH 7.4 medium, acidic transfection medium reduced gene expression 1.6-7.7-fold whereas acidic culture medium enhanced transfection efficiency 2.1-2.6-fold. Polymeric transfection was affected more by the culture medium than by the transfection medium. Understanding the effects of extracellular pH during polymeric transfection may stimulate new strategies for determining effective and safe polymeric gene carriers.     

Physicochemical parameters of non-viral vectors that govern transfection efficiency

Gene therapy is based on the vectorization of nucleic acids to target cells and their subsequent expression. Cationic lipids and polymers are the most widely used vectors for the delivery of DNA into cultured cells. Nowadays, numerous reagents made of these cationic molecules are commercially available and used by researchers from the academic and industrial field. By contrast their evaluations in preclinical programs have revealed that their use for in vivo applications will be more problematic than their massive use in vitro. This is mostly due to the physicochemical properties of cationic vectors/DNA complexes, which are the result of their mode of interaction. Indeed, these cationic vectors interact through electrostatic forces with negatively charged DNA. This results in the formation of highly organized positively charged supramolecular structures where DNA molecules are condensed. Association of DNA with cationic lipids under a micellar or liposomal form leads to lamellar organization with DNA molecules sandwiched between lipid bilayers. Although the lamellar phase is the common described structure, as evidenced by small-angle X-ray scattering and electron microscopy, some cationic lipid combined with a hexagonal forming lipid could also result with DNA in an inverted hexagonal structure. Despite a lot of effort, the precise mechanism of gene transfer with cationic vector is still ill-defined. Here, our objective was to overview the main relationships between the physico chemical properties of cationic lipid/DNA complexes and their transfection efficiency. An overview of a new class of vectors consisting of amphiphilic block copolymers designed for in vivo delivery is also presented and discussed.     

High efficiency transfection of monkey kidney COS-1 cells

Summary Methods are described for achieving high efficiency transient transfection of COS-1 cells. A transfection solution of vector DNA and DEAE-dextran in phosphate buffered saline is added to the cells, followed by treatment with culture medium containing chloroquine, resulting in a maximum efficiency of about 50%. The high efficiency obtained is primarily dependent on the use of Ca²⁺- or Mg²⁺-free buffer solutions for transfection, because the addition of these ions greatly reduces efficiency. Shocking the cells with dimethylsulfoxide does not increase transfection efficiency. COS-1 cells are monkey kidney cells that have a genomic insertion of the SV40 T antigen gene, allowing plasmid expression vectors bearing an SV40 replication origin to be amplified in these cells. Therefore this transfection method is useful for optimizing transient expression of genes in a mammalian cell system.     

TBK1 inhibitors enhance transfection efficiency by suppressing p62/SQSTM1 phosphorylation

DNA transfection is an essential technique in the life sciences. Non-viral transfection reagents are widely used for transfection in basic science. However, low transfection efficiency is a problem in some cell types. This low efficiency can be primarily attributed to the intracellular degradation of transfected DNA by p62-dependent selective autophagy, specifically by p62 phosphorylated at the S403 residue (p62-S403-P). To achieve efficient DNA transfection, we focused on a phosphorylation process that generates p62-S403-P and investigated whether inhibition of this process affects transfection efficiency. One of the kinases that phosphorylate p62 is TBK1. The TBK1 gene depletion in murine embryonic fibroblast cells by genome editing caused a significant reduction or loss of p62-S405-P (equivalent to human S403-P) and enhanced transfection efficiency, suggesting that TBK1 is a major kinase that phosphorylates p62 at S403. Therefore, TBK1 is a viable target for drug treatment to increase transfection efficiency. Transfection efficiency was enhanced when cells were treated with one of the following TBK1 inhibitors BX795, MRT67307, or amlexanox. This effect was synergistically improved when the two inhibitors were used in combination. Our results indicate that TBK1 inhibitors enhanced transfection efficiency by suppressing p62 phosphorylation.     

Factors influencing the transfection efficiency of ultra low molecular weight chitosan/hyaluronic acid nanoparticles

The present work describes nanoparticles made of ultra low molecular weight chitosan (ULMWCh)/hyaluronic acid (HA) as novel potential carriers for gene delivery. Small and monodispersed nanoparticles with high in vitro transfection capabilities have been obtained by the complexation of these two polyelectrolytes. ULMWCh (<10 kDa) presents more advantageous characteristics over the higher molecular weight chitosan for clinical applications, namely increased solubility at physiological pH and improved DNA release. The ULMWCh:HA ratio and the HA molecular weights were varied with the aim of obtaining particles in the 100 nm range. Using chitosan (Ch) with a molecular weight of 5 kDa, HA with a molecular weight of 64 kDa, and a weight ratio of 4:1, nanoparticles with a Z-average size of 146 ± 1 nm and narrow size distribution (polydispersity index: 0.073 ± 0.030) were obtained. Nanoparticle images taken in dry conditions by SEM and AFM showed spherical particles. The optimal pH for transfection ranged from 6.4 to 6.8 for 0.25 μg of EGFP plasmid per well, with an incubation time of 4 h. Using these optimized parameters, DNA/ULMWCh:HA nanoparticles successfully transfected 25 ± 1% of the 293T cells with pEGFP, compared to 0.7% obtained for DNA/ULMWCh under the same conditions. This high transfection efficiency of our non-viral gene delivery system could be attributed to the synergic effect of ULMWCh and low charge density of the HA chain for easy release of DNA which makes the system suitable for targeted gene delivery.