Formation of a DNA/N-dodecylated chitosan complex and salt-induced gene delivery

An N-dodecylated chitosan (CS-12) was synthesized from dodecyl bromide and chitosan and was assembled with DNA to form a polyelectrolyte complex (DNA/ CS-12 PEC). UV was used to examine the thermal stability of DNA embedded in PEC. The results indicate that the incorporation of dodecylated chitosan c an enhance the thermal stability of DNA. The analysis of AFM image shows th at PEC develops a globule-like structure composed of 40-115 DNA molecules. Dissociation of PEC was investigated by the addition of low molecular weigh t electrolytes. The added small molecular salts dissociate the PEC, inducin g DNA to release. The ability of Mg2+ to dissociate PEC is greater compared to that of Na+ and K+. From AFM images, it can be visualized that DNA rema ins intact and undamaged due to the protection from DNase offered by alkyla ted chitosan. (C) 2001 John Wiley & Sons, Inc.