Synthesis Of Chitosan Derivatives And Application Of Gene Delivery

Gene therapy aims to act on the genetic cause of a pathology by gene inhibition or substitution.In order to achieve a therapeutic effect,Gene delivery systems are essential to deliver nucleic acids into the cells.Chitosan is a linear polysaccharide that displays properties such as biocompatibility and biodegradability,and is applied in gene delivery research.This work introduces a new chitosan-based polymer: N-(2-enylamino)-6-O-glycol chitosan(EAGC).The new polymer aims to overcome the disadvantages of chitosan for gene delivery,such as poor solubility at physiological pH and low buffer capacity,in order to enhance its transfection efficiency while retaining its main benefits of low toxicity and biocompatibility.Four batches of EAGC were synthesized with different degrees of ethylamino substitution: EAGC11,EAGC17,EAGC21 and EAGC29.The agarose gel retardation assay revealed that all polymers had the ability to condense with DNA/RNA at different polymer: DNA/RNA mass ratios.The nanoparticles formed with EAGC and DNA/RNA presented sizes between 100 and 450 nm with a positive charge of 40 mV and spherical shape.EAGC17,EAGC21,and EAGC29 polymers were able to deliver the β-galactosidase DNA to A431 cells in vitro.EAGC29 showed the best transfection capacity at lower polymer: DNA mass ratios.EAGC11 was able to deliver the β-galactosidase mRNA to A431 cells in vitro.Differences in charge density of the polymers resulted in differnet gene activity.Nevertheless,all EAGC polymers were superior transfection agents to lipofectamine,particularly at high polymer: DNA/RNA mass ratios.The results of this study confirmed EAGC as a good candidate for in vitro gene delivery.