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To develop a novel vector for gene delivery with low molecular weight polyethylenimine grafted to the natural polysaccharide and conjugated to folic acid (LNT-PEI-FA).The properties of LNT-PEI-FA were characterized by (1)H-NMR, FT-IR and TGA, respectively. The particle size of LNT-PEI-FA/DNA complex was measured. The DNA binding ability of LNT-PEI-FA was detected by gel electrophoresis retardation assay.The particle size of LNT-PEI-FA/DNA complex was about 200 nm. Gel electrophoresis showed that at N/P ratio of 1.8 (W/W) the polymer was able to completely condense DNA. In vitro experiments showed a high efficiency of gene transfection in A293 and B16 cell lines.A novel non-viral vector LNT-PEI-FA was successfully synthesized and characterized, which may be applied in gene transfection research in the future.

To develop a novel gene delivery vector with poly-aspartamide-glutamic acid and polyethylenimine as the backbone.alpha, beta-poly-(N-2-hydroxypropyl)-D, L-aspartamide-glutamic acid (PHPAG) was synthesized and low molecular weight polyethylenimine (PEI 1.8 kDa) was grafted to form PHPAG-PEI 1800. Chemical and biological characterization of the polymer was identified.The polymer was confirmed by (1)H-NMR, and the molecular weight was about 1.2 x 10(4). The ability of DNA binding was showed by gel retardation assay at N/P ratio of 3. 5. MTT assay showed that the polymer was non toxic in COS-7 and A293 cell lines. In vitro test demonstrated that it had high transfection efficiency in B16 and Hela cell lines.PHPAG-PEI 1800 was successfully synthesized,which might be a potential vector for gene delivery.

To develop a new prodrug of 5-fluorouracil-polyethylenimine-beta-cyclodextrin-floxuridine (PEI-beta-CyD-Fd) and to test its antitumor activity.Floxuridine was conjugated to polyethylenimine-beta-cyclodextrin to form prodrug PEI-beta-CyD-Fd. The structure of synthesized PEI-beta-CyD-Fd was confirmed by (1)H-NMR, FT-IR and UV. MTT assay and cell wound healing assay were performed on human hepatic carcinoma cell line HepG2.The drug loading was 2 %. The MTT assay and cell wound healing assay indicated that PEI-beta-CyD-Fd significantly inhibited proliferation and migration of HepG2 cells.The synthesized prodrug PEI-CyD-Fd has a significant antitumor activity on HepG2 cells.

To develop a novel non-viral gene delivery vector CY11-PEI-beta-CyD and to test its gene transfection efficiency.CY11 (CGMQLPLATWY) was conjugated to polyethylenimine-beta-cyclodextrin to form CY11-PEI-beta-CyD with a cross-linker [N-succinimidy-3-(2-pyridyldithio) propionate, SPDP]. (1)H-NMR and TGA were used to confirm the structure of vector. The DNA condensing ability of CY11-PEI-beta-CyD was investigated by gel retardation assay. Cytotoxicity of CY11-PEI-beta-CyD was determined by MTT assay and transfection efficiency was investigated in COS-7, Hela and B16 cells.CY11 was conjugated onto PEI-beta-CyD successfully, confirmed by(1)H NMR and TGA. The novel vector effectively condensed DNA at N/P ratio of 4îIt showed low cytotoxicity up to the concentration was 160 Mgr;g/ml. The transfection efficiency was 17-fold higher than that of PEI 25 kDa at N/P ratio of 20.The novel vector CY11 -PEI-beta-CyD with low cytotoxic and high transfection efficiency may be used as a potential carrier for gene delivery.

To develop a novel non-viral gene delivery vector based on polyethylenimine and beta-cyclodextrin targeting to Her-2 receptor (MC10-PEI-beta-CyD).The PEI-beta-CyD was synthesized by low molecular weight polyethylenimine (PEI, Mw 600) cross-linked beta-cyclodextrin (beta-CyD) via N, N-carbonyldiimidazole (CDI). The chemical linker[N-succinimidy-3-(2-pyridyldithio) propionate, SPDP] was used to bind peptide MC10 (MARAKEGGGC) to PEI-beta-CyD to form the vector MC10-PEI-beta-CyD. The (1)H-NMR was used to confirm the structure of vector. The DNA condensing ability,and the particle size of MC10-PEI-beta-CyD/DNA complexes were demonstrated by gel retardation assay and electron microscope observation (TEM). Cell viability was tested by MTT assay. The transfection efficiency was determined on cultured SKOV-3, A549 and MCF-7 cells.MC10 was linked onto PEI-beta-CyD successfully. The vector was able to condense DNA at N/P ratio of 5 and particle size was about (170 +/-35)nm. The vector showed low cytotoxicity and high transfection efficiency in cultured SKOV-3, A549 and MCF-7 cells.A novel non-viral vector MC10-PEI-beta-CyD with low cytotoxicity and high transfection efficiency has been successfully synthesized.

To develop a novel gene delivery vector TAT-PEI-beta-CyD.beta-cyclodextrin (beta-CyD) was linked by low molecular weight (PEI 600) via 1, 1-carbonyldiimidazole (CDI), and TAT peptide (RRRQRRKKRC) was coupled to PEI 600 by [N-succinimidy-3-(2-pyridyldithio) propionate, SPDP]. The copolymer was characterized by (1)H-NMR and FT-IR. Physiochemical characteristics of TAT-PEI-beta-CyD/DNA complexes were tested by agarose gel electrophoresis and particle size measurements. Cell viability and transfection efficiency were evaluated in A293 and B16 cells using PEI 25 kDa as a control.TAT peptide was successfully coupled to PEI-beta-CyD. The result of gel electrophoresis showed that the TAT-PEI-beta-CyD was able to condense DNA efficiently at N/P ratio of 4. The particle size of TAT-PEI-beta-CyD/DNA complexes was around 100 nm. The cytotoxicity of TAT-PEI-beta-CyD was lower than that of PEI 25 kDa. The transfection efficiency of TAT-PEI-beta-CyD was higher than that of PEI 25 kDa in A293 and B16 cells at N/P ratio of 30.The novel vector TAT-PEI-beta-CyD has been developed successfully with low cytotoxicity and high transfection efficiency.