title: Synthesis of (Dex-HMDI)-g-PEIs as effective and low cytotoxic nonviral gene vectors.
abstract: Gene vectors, (dextran-hexamethylenediisocyanate)-g-polyethylenimines ((Dex-HMDI)-g-PEIs), were synthesized through grafting low molecular weight (800 Da) branched polyethylenimine (PEI) to HMDI functionalized dextrans with two different molecular weights. The buffer capabilities of (Dex-HMDI)-g-PEIs were examined by acid-base titration. The titration profiles show that both (Dex-HMDI)-g-PEIs have the similar buffer capability regardless of the different molecular weight of dextran. Physiochemical characteristics of (Dex-HMDI)-g-PEI/DNA complexes were analyzed by agarose gel electrophoresis, and particle size and zeta-potential measurements. The result of gel electrophoresis suggests that both (Dex-HMDI)-g-PEIs are able to condense DNA efficiently at N/P ratios higher than 4. The particle sizes of (Dex-HMDI)-g-PEI/DNA complexes are around 160-250 nm, and the surface charges are around 19-23 mV at the N/P ratios ranging from 10 to 60. The morphology of complexes was observed by scanning electron microscopy (SEM) and the images show that nano-sized complexes display a regular spherical shape. In vitro cell viability and transfection were evaluated in 293T and HeLa cells using 25 kDa PEI as a control. The cytotoxicity of (Dex-HMDI)-g-PEIs is lower than that of 25 kDa PEI. The gene transfection efficiency of (Dex-HMDI)-g-PEI/DNA complexes at certain N/P ratios in 293T cells is higher than or comparable to 25 kDa PEI/DNA complex at its optimal N/P ratio of 10. In addition, comparing with (Dex-HMDI)-g-PEI with a high molecular weight dextran, (Dex-HMDI)-g-PEI with a low molecular weight dextran demonstrates lower cytotoxicity and higher transfection efficiency.
authors.affiliation: Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Yun-Xia
authors.initials: YX
authors.lastname: Sun
authors.forename: Wang
authors.initials: W
authors.lastname: Xiao
authors.forename: Si-Xue
authors.initials: SX
authors.lastname: Cheng
authors.forename: Xian-Zheng
authors.initials: XZ
authors.lastname: Zhang
authors.forename: Ren-Xi
authors.initials: RX
authors.lastname: Zhuo
mesh_terms: D002021:Buffers; D002460:Cell Line; D002470:Cell Survival; D003485:Cyanates / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D017953:Isocyanates; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D010316:Particle Size; D010957:Plasmids / Q000737:chemistry / Q000235:genetics; D011094:Polyethyleneimine / Q000031:analogs & derivatives* / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013499:Surface Properties; D017186:Titrimetry; D014162:Transfection
chemical_list: D002021:Buffers; D003485:Cyanates; D003911:Dextrans; D017953:Isocyanates; C015262:1,6-hexamethylene diisocyanate; D049452:Green Fluorescent Proteins; D011094:Polyethyleneimine; D008156:Luciferases