An influence of molecular weight, deacetylation degree of chitosan xerogels on their antimicrobial activity and cytotoxicity. Comparison of chitosan materials obtained using lactic acid and CO2 saturation

This paper presents a comparison of the antimicrobial activity and cytotoxicity against L929 cells of chitosan xerogels prepared by dissolving the polymer in a solution of lactic acid (LA) or carbonic acid (CO2) and then freeze-drying. There was no simple relationship between the antimicrobial activity and cytotoxicity of the samples obtained using both techniques (LA and CO2). Chitosan materials obtained by the LA method in a 1:1 dilution were characterized by the highest cytotoxicity against L929 cells (similar to 20%). For the same diluted samples prepared using the CO2 saturation method, the viability of L929 cells was approximately 2.5 times greater. Some of the tested chitosan materials obtained by the innovative method were characterized by significantly lower antimicrobial activity, for example, reduction of E. coli bacteria for MMW-LA and MMW-CO2 samples by 6.00 and 0.75 logarithmic order, respectively. This clearly indicates that in many applications, the presence of the acid necessary to dissolve chitosan is responsible for the antimicrobial activity of the polymer solution and its products.