Synthesis of strong polycations with improved biological properties

Poly(allylamine hydrochloride) (PAH) has found many applications both in biotechnology and biomedical fields. However, its high toxicity toward various mammalian cells significantly limits its effective usage. This study focuses on improving the biological properties of PAH by its modification to strong polyelectrolytes. The strong polycations were prepared by the direct quaternization of PAH amino groups or by the attachment of glycidyltrimethylammonium chloride to these groups. The biological properties, such as cytotoxicity toward human skin fibroblasts (HSFs), proliferation and migration of the cells on a polymeric surface, and antibacterial activities against two pathogenic bacteria, Staphylococcus aureus and Escherichia coli, were determined. All the modified polyelectrolytes are considerably less toxic to HSFs as compared to PAH. Moreover, the directly quaternized polycations are stronger biocides against S. aureus than the parent polymer. Contrary to PAH, thin films of the modified polyelectrolytes improve or do not affect HSFs proliferation and can stimulate cell migration into the wound, as was demonstrated using an in vitro model. The relationship between the structure of the modified polymers (amount and localization of the quaternary ammonium groups) and the biological activity is discussed. Due to the improved biological properties, the obtained polycations may be potentially useful for a variety of biotechnological and biomedical applications.