Water-Soluble Polyplexes of Modified Chitosan

The alkylation of primary amino groups of chitosan with glycidyltrimethylammonium chloride yields the modified cationic polysaccharide that carries, in practically every deacetylated unit, a secondary amino group and a quaternized amino group that provide the solubility of the polymer over the whole range of pH values. The mixing of solutions of modified chitosan and nucleic acid in neutral solutions at various ratios gives soluble DNA-containing polyelectrolyte complexes (polyplexes) that preserve stability under physiological conditions. The effects of the pH, ionic strength, and charge-to-charge ratio of polymer components on the boundaries of existence of soluble polyplexes both negatively and positively charged are elucidated. The collected experimental data may serve as a basis for designing biocompatible and biodegradable means for the delivery of genetic material and drugs to living cells.