Succinated chitosan as a gene carrier for improved chitosan solubility and gene transfection

Chitosan (CHI), a linear polysaccharide, has been intensively studied as a nonviral gene delivery vector. The low physiological solubility of CHI has limited its gene transfection efficiency. Here we report the synthesis of different substitution degrees of succinated chitosans (CHI-succ) to increase water solubility. According to the proton nuclear magnetic resonance spectra, the degree of deacetylation of hydrolyzed CHI was roughly 88% and the degrees of succinylation in three CHI-succ polymers were approximately 5, 10, and 20%. Various weight ratios of CHI/DNA and CHI-succ/DNA polyplexes were prepared for gel electrophoresis retardation, particle size, zeta potential, and morphology studies. The results suggest that the plasmid DNA is readily entrapped at a CHI-succ/DNA weight ratio of 20; the sizes and zeta potentials were between 110 and 140 nm and ±1-5 mV, and the polyplexes exhibited low cytotoxicity against HEK 293T cells. CHI-succ with 5 and 10% degrees of substitution showed improved transfection efficiency as compared with nascent CHI.

Chitosan, a cationic polysacchride with gene therapy potential, has inherently poor water solubility, which is improved by partial succinylation according to this report. The new DNA/Chitosan polyplexes exhibit improved safety against HEK 293T cells.