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Poly (β-amino ester)s (PβAEs) contain tertiary amine backbones and biodegradable ester bonds, making them highly biocompatible and pH-responsive. Meanwhile, originated from combinatorial libraries, PβAEs are simple to synthesize, easy to obtain raw materials and can be easily adapted to meet the different performance needs of gene carriers by adjusting the monomer type, monomer ratio and reaction time. Therefore, PβAEs are promising material for non-viral gene carriers. This paper provides a comprehensive overview of the properties and synthesis of PβAEs gene carriers and summarizes the progress of research on the gene delivery of each type of PβAEs.
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@#Nowadays, there is still no mature gene delivery system for safe and effective transfection on primary dendritic cells (DC). Herein, we constructed a liposome-based gene delivery system for primary DCs and optimized the preparation method to improve the transfection efficiency of siRNA on primary DCs. In this study, different methods, including co-incubation method, ethanol injection method, and protamine compound method, were used to prepare liposome/siRNA complexes based on different cationic lipids. Moreover, particle size, zeta potential, siRNA loading capacity, safety, stability, uptake efficiency and gene silencing efficiency of various liposome/siRNA complexes were detected to screen the optimal cationic lipid as well as its preparation method. We demonstrated that the OA2/siRNA delivery system prepared by the co-incubation method exhibited the best safety, uptake efficiency and gene silencing effect, compared to other siRNA delivery systems including the commercial Lipo2000. In summary, we provide a safe and effective gene delivery vector for primary DC cells through simple preparation method, which could also offer a gene delivery platform for other immune cells.
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In recent years, non-viral gene vectors have attracted great attention for efficient gene delivery due to the advantages, including low toxicity, low immunogenicity and simple preparation. Polyethylenimine (PEI) is one of the typical non-viral gene carriers that have been widely utilized for gene delivery owing to its superior capabilities in gene compression and buffering capacity. This article discusses the processes of gene delivery and the barriers of PEI-based carrier during the gene delivery, such as low biocompatibility, cytotoxicity, lack of specific targeting and insufficient gene release, etc. Therefore, we summarize the multiple approaches for the modifications of PEI in terms of improved biocompatibility, degradability, specific targeting and buffering capacity. Furthermore, we also review on the recent impressive progresses of smart stimuli-responsive PEI carriers, including endogenous stimuli (pH, reactive oxygen species, glutathione, biomolecular, etc), exogenous stimuli (light, temperature, magnetic field, etc) and dual-responsive strategies, which might provide guidance for the development of more efficient and safer non-viral gene vectors.
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This study was designed to reverse multidrug resistance of lung cancer cells by downregulating MDR1 genes through RNA interference (RNAi) technology. A novel biodegradable cationic polymer (PEG-bPLG-g-PEIs, GGI) was synthesized and characterized by 1H NMR. The particle size and zeta potential were measured by dynamic light scattering (DLS). The cell viability profile of GGI was tested by MTT method with both A549 and A549/DDP cell lines. Flow cytometry (FCM) technology was used to investigate the efficiency and intensity of delivering siRNA to cells by GGI polymer. RT-PCR and Western blot were used to detect the mRNA and P-gp expression after GGI/MDR1 siRNA transfection assay. The sensitivity of cisplatin administration after transfecting GGI/MDR1 siRNA polyplexs was performed with MTT and Annexin V-FITC/PI methods. The results suggest that the particle size and zeta potential of GGI/siRNA were 150-200 nm and 16-28 mV. GGI exhibited a lower cell cytotoxity than PEI 25K and higher efficiency of delivering siRNA, which dramatically decreased the expression of MDR1 mRNA and P-gp of A549/DDP cells and increased much sensitivity to cisplatin in A549/DDP cells. GGI holds a great potential in gene delivery as a novel cationic polymer for further investigation.
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Objective To prepare a microRNA (miRNA) delivery system using the branched polyethyleneimine (BPEI), linear polyethylenimine (LPEI) and polyamidoamine dendrimers (PAMAM) loaded with miRNA-15a and miRNA-16-1, which can inhibit prostate cancer PC3 cell proliferation, and to examine the zeta potential, intracellular uptake, and the inhibition effect on PC3 cells of the three constructed nano-complexes. Methods Particle size analyzer was used to determine the size and potential of the three kinds of nano-complexes, and the miRNA affinity capability of them was determined by agarose gel electrophoresis retardation assay. The uptake efficiency of the nano-complexes by PC3 cells was examined by NC-miRNA labeled with FAM. CCK8 method was used to determine the inhibitory effect of the nano-complexes loaded with miRNA-15a and miRNA-16-1 against PC3 cells, and PCR was used to analyze their inhibitory effect on expression of Bcl-2, Cylin D1 and Wnt3a gene in PC3 cells. Results BPEI, LPEI and PAMAM loaded with miRNA could form stable nano complexes. When N/P = 5, the intracellular uptake of BPEI/miRNA-FAM by PC3 cells was significantly higher than that of LPEI/miRNA-FAM and PAMAM/miRNA-FAM (P<0.05). BPEI, LPEI and PAMAM could all carry miRNA-15a and miRNA-16-1 into PC3 cells and block Bcl-2,Cylin D1 and Wnt3a expression in PC3 cells. Conclusion BPEI, LPEI and PAMAM loaded with miRNA-15a and miRNA-16-1 can suppress proliferation of prostate cancer PC3 cells and block Bcl-2,Cylin D1 and Wnt3a expression.
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Objective To synthesize PEG-P[Asp(DET)] with 10% cholesterol chloroformate modified on its side chain and to study the physicochemical properties and cellular uptake of polymer complex PEG-P[Asp(DET)]-chole/hsa-miR-15a. Methods PEG-P[Asp(DET)] was synthesized by ring opening polymerization and modification with cholesterol chloroformate to acquire hydrophobicity, and MRI was used to verify its structure. The particle size, Zeta potential, stability, encapsulation efficiency, and cytotoxicity of the polymer complex PEG-P[Asp(DET)]-10% chole/hsa-miR-15a were examined. Finally, in vitro cellular uptake experiment was carried out with the leukemia cell line K562. Results The synthesized polymer PEG-P[Asp(DET)]-10% chole had fine solubility and could form into stable polymer complex PEG-P[Asp(DET)]-chole/hsa-miR-15a. When nitrogen-phosphorus ratio (N/P) was at 20 and concentration of the miRNA was 5 μmol/mL, the particle size was (192. 4±10. 8) nm, Zeta potencial was (6. 9±0. 9) mV, andencapsulation efficiency was (90. 5±3. 2)%. The complex displayed good stability under experimental condition. In vitrr cellular uptake experimental indicated that the uptake capacity of PEG-P[Asp(DET)]-10%chole/hsa-miR-15a was higher than that of the commercial agent lipo2000. Conclusion PEG-P[Asp (DET)]-10%chole is a fine gene polymer carrier for miRNA and can achieve stable cellular uptake of miRNA.
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Cationic polymers are being developed quickly as gene delivery vectors. For in vivo gene delivery, the cationic polymers are usually further modified by hydrophilic polymer grafting or ligand conjugation, which have been shown to increase the vector stability, gene delivery efficiency and specificity greatly. Some previous research had shown that modified hydrophilic polymer may partly shield the targeting ligand and result in poor delivery specificity. Developing a method to evaluate the influence of PEG modification on targeting delivery is particularly critical to cationic polymer design and gene therapy development. One of most commonly used cationic polymer polylysine (PLL) was chosen as a model. Targeting ligand epidermal growth factor(EGF)was conjugated with PLL to form PLL-EGF. Then hydrophilic polymer polyethylene glycol (PEG) with molecular mass 7 000 and 20 000 were used to modify PLL-EGF respectively to generate PEG7000-g-PLL-EGF and PEG20000-g-PLL-EGF. In BIAcore experiments, epidermal growth factor receptor (EGFR) was conjugated onto BIAcore chip and various PEG modified PLL-EGF solutions were flowed over the chip. By observing the change of RU value, the specific interaction of EGF to EGFR was compared. Compared with PLL-EGF, PEG modified PLL-EGF showed lower association rate and higher disassociation rate to EGFR. Furthermore, compared to PEG7000 modified PLL-EGF, PEG20000 modified PLL-EGF got lower association rate and higher disassociation rate to EGFR. The Scatchard analysis results showed that the interactions between EGFR and PLL-EGF or PEG-PLL-EGF are non-linear. It can be concluded that PEG modification indeed reduced the association rate and enhanced the dissociation rate of EGF to EGFR. The length of PEG chain was also a key factor to influence interaction between ligand and receptor. The results showed that it was critical important to evaluate the influence of PEG modification on delivery specificities. The BIAcore method developed in this paper can successfully evaluate the influence, which would be important for cationic polymer design and its application as potential non-viral gene delivery vectors.