| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 가을 (10/13 ~ 10/14, 제주 ICC) |
| 권호 | 30권 2호 |
| 발표분야 | 의료용 고분자 부문위원회 |
| 제목 | Characterization of low molecular water-soluble chitosan/plasmid DNA complex according to pH by dynamic light scattering |
| 초록 | This study investigates the potential of low molecular water-soluble chitosan and its derivatives as a novel biomaterial. Amine group of glucosamine unit in the structure of chitosan has several advantages as a gene carrier such as non-cytotoxicity and strong positive charge which facilitates formation of the complex with DNA. Since chitosan was first described as a delivery system for plasmids by Mumper et al., many studies have been conducted for delivery of genes safely in the body. The particle size of the complex is very important for gene expression. It has already been reported that endocytosis by many types of mammalian cells is limited to particles less than about 150 nm in diameter. The suitable size of the complex for gene delivery is around 100 nm. It has been suggested that the polymer/plasmid DNA complex with a diameter of around 100 nm corresponds to the diameter of the coated pits in endocytosis. To confirm the size of LMWSC/DNA, LCP/DNA, and LCP-Ch/DNA complex, the particle size and zeta potential were measured by DLS. Generally, chitosan is more stable under a weak acidic condition because its pKa value is pH 6.2-6.8. Also, the particle size of the complex is dependent on the ratio and concentration of the polymer/plasmid DNA complex. We investigated the tendency of the complex size according to the pH condition. The particle size of complexes was different according to the pH of media. Particle sizes at the pH 6.5 and 7.0 were about 100~120 nm and 120~160 nm, respectively. Because LMWSC at the pH 6.5 has the strong positive charge, it formed the compact complex with the plasmid DNA. The surface charge of the complex also depended on the pH. At pH 6.5, the surface charge of the complex was higher than that at pH 7.0. The zeta potential of the LCP modified with PEG or of the LCP-Ch modified with cholesterol has lower positive value than that of LMWSC because of the decrease of the positive charge. The morphologies of the complexes by TEM were of well-formed spherical shape with the average diameters of about 100 ~ 150 nm. Among the three gene carriers, LCP-Ch/plasmid DNA showed the highest gene expression owing to the hydrophobic interaction between cell surface and cholesterol. No cytotoxicity was observed in the gene carriers investigated in this study at various concentrations. |
| 저자 | 장미경, 김동곤, 나재운 |
| 소속 | 순천대 |
| 키워드 | LMWSC; dynamic light scattering; biomaterial |
