Thesis (M.Sc. in Pharm.)--Chulalongkorn University, 2011

The functionalized multiwalled carbonnanotube-chitosan-plasmid DNA (M/C/D) nanoparticles were prepared by using electrostatic interaction. Multiwalled carbonnanotube(MWCNTs) were functionalized by treating with concentrated sulfuric acid and concentrated nitric acid to improve solubilization and to obtain anionic particles. The percentage of product yield was related to the time that the pristine MWCNTs were contacted to oxidizing agent. The average particle size of functionalized MWCNTs (f-MWCNTs) was 68 to 84.63 nm and zeta potential was -22.44 to -9.58 mV. Chitosan nanoparticles were harmonized with f-MWCNTs for pDNA binding. The electrostatic interactions between f-MWCNTs/CS and pDNA were confirmed by increasing the size distribution and decreasing the zeta potential of formulations. pDNA, 3:1 M/C and the ratio of 3:1:1, 1:11:1, 1:13:1, 1:15:1, 1:17:1 M/C/D nanoparticles presented no noticeable morphology modification of HeLa cells in the 5% CO2 humidified incubator at 37ᵒC for 72 hours. Lipofectamine® and Lipofectamine®-pDNA revealed that HeLa cells reform to round cells and resulted in cell death. f-MWCNTs at concentration below 75 µg/ml was nearly 100% cell viability. The transfection efficiency of formulations determined by the GFP-related fluorescence expression after incubated with formulations for 48 hours. 5:3:1 M/C/D formulation was significantly different compared with negative control (pDNA) (P<0.05). High concentration of f-MWCNTs in nanocomposite could improve the transfection efficiency even though the transfection efficiency of M/C/D formulation was still lower than that of PolyFect® and Lipofectamine.