title: A novel chitosan oligosaccharide-stearic acid micelles for gene delivery: properties and in vitro transfection studies.
abstract: Stearic acid (SA) grafted chitosan oligosaccharide (CSO) (CSO-SA), which was synthesized by an 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)-mediated coupling reaction, was demonstrated to form micelle like structure by self-aggregation in aqueous solution. The critical micelle concentration (CMC) of CSO-SA with 15.4% amino substituted degree of CSO was about 0.035 mg/ml. The micelles with 1mg/ml CSO-SA concentration had 70.6 nm volume average hydrodynamic diameter with a narrow size distribution and 46.4+/-0.1 mV surface potential. Due to the cationic property, the micelles could compact the plasmid DNA to form micelle/DNA complexes nanoparticles, which can efficiently protect the condensed DNA from enzymatic degradation by DNase I. The volume average hydrodynamic diameter of CSO-SA micelle/DNA complex increased from 203 nm to 318 nm and decreased to 102 nm due to the variation of zeta potential when the N/P ratio increased from 0.25 to 3.6 and from 3.6 to 58. The IC(50) value of the CSO-SA micelle against A549 cells was 543.16 microg/ml, while the IC(50) of Lipofectamine 2000 was about 6 microg/ml. The in vitro transfection efficiency of CSO-SA micelles was investigated by using plasmid DNA (pEGFP-C1). The transfection efficiency with CSO-SA/DNA (N/P ratio is 29) was increased with the post-transfection time (in 76h), while the optimal transfection of Lipofectamine 2000/DNA was obtained at 24h. The transfection of CSO-SA was not interfered in the presence of 10% fetal bovine serum, which showed remarkable enhancement effect. The optimal transfection efficiency of CSO-SA micelles in A549 cells was about 15%, which was higher than that of CSO (about 2%) and approach to that of Lipofectamine 2000 (about 20%). The low cytotoxic biodegradable CSO-SA micelles could be used as an effective DNA condensation carrier for gene delivery system.
authors.affiliation: College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310031, PR China. hufq@zju.edu.cn
authors.forename: Fu-Qiang
authors.initials: FQ
authors.lastname: Hu
authors.forename: Meng-Dan
authors.initials: MD
authors.lastname: Zhao
authors.forename: Hong
authors.initials: H
authors.lastname: Yuan
authors.forename: Jian
authors.initials: J
authors.lastname: You
authors.forename: Yong-Zhong
authors.initials: YZ
authors.lastname: Du
authors.forename: Su
authors.initials: S
authors.lastname: Zeng
mesh_terms: D002412:Cations; D048271:Chitosan / Q000737:chemistry*; D004337:Drug Carriers; D008823:Micelles; D010316:Particle Size; D013229:Stearic Acids / Q000737:chemistry*; D014162:Transfection / Q000379:methods* / Q000592:standards
chemical_list: D002412:Cations; D004337:Drug Carriers; D008823:Micelles; D013229:Stearic Acids; C031183:stearic acid; D048271:Chitosan