Lignin-containing polyethylene films with antibacterial activity

Abstract

Estimated more than 60% of bacterial infections currently treated in hospitals are caused by bacterial biofilms. Polyethylene catheters show a high risk of bacterial colonization. The prevention of biofilm formation is therefore a necessary step in the successful prophylaxis of such infections. One of the methods to protect polymer biomaterials is an incorporation of organic or inorganic additives with antibacterial efficiency to the polymer matrix during polymerization or processing. In chemistry, pharmacy and medical practice a number of antimicrobial agents is used. In the presented investigation we compare the antibacterial effectiveness of Bjorkman lignin isolated from beech wood to Bronopol, Benzalkonium chloride, Chlorhexidine and Silver nitrate. Polyethylene films with 2 wt% of antibacterial additives were prepared by solution casting from boiling xylene with consequential compression molding. Antibacterial activity against Escherichia coli and Staphylococcus aureus was determined by agar diffusion test. A polyethylene film without antibacterial additive showed bacterial growth. All tested antibacterial additives proved antimicrobial activity determined by the means of inhibition growth zones in millimeters. The effect of Bjorkman beech lignin is comparable with Bronopol and Chlorhexidine. The highest antibacterial activity was recorded for Benzalkonium chloride. These results indicate that the nano-Bjorkman lignin (particle size up to 60 nm) isolated from beech wood has great potential as antibacterial agent for polymer blends. Moreover, stress-strain analyses of the prepared films showed that the addition of 2 wt% nano-Bjorkman lignin did not alter the mechanical properties of polyethylene films. © 2011 TANGER Ltd., Ostrava.