Effect of formulation variables on physical properties and transfection efficiency of chitosan-dna nanoparticles

Abstract

Chitosan-pDNA nanoparticles were prepared by using complex coacervation method. The effect of formulation variables, medium of chitosan, medium of pDNA and N/P ratio, on physical properties and transfection efficiency were examined. The particle size of the nanoparticles sharply decreased with increasing N/P ratio and became stable to constant value of 102-278 nm with PI in the range of 0.20-0.51. The zeta potential increased from negative charge to positive charge with increasing N/P ratio and finally increased to constant value in the range of +7.70 to +33.53 mV. The particle size and zeta potential were affected by all experimental variables. TEM images of nanoparticles showed that most nanoparticles had spherical shape, while a few particles had rod shape. The electrophoretic mobility analysis showed that the nanoparticles formation occurred at N/P ratio from 0.5:1 to 7:1 and the nanoparticles could render protection from deoxyribonuclease to pDNA. Flow cytometry and fluorescence microscopy were used to evaluate in vitro transfection efficiency in HeLa cells. The in vitro transfection efficiency of chitosan-pDNA nanoparticles was higher than that of naked pDNA and comparable to the positive control, LipofectamineTM Reagent. The N/P ratio and medium of pDNA affected transfection efficiency. MTT assay used in cell viability study demonstrated that chitosan did not affect the viability of HeLa cells.