Antimicrobial films obtained from latex particles functionalized with quaternized block copolymers

• Antimicrobial films were obtained from functional latex particles containing cationic block copolymers as polymeric surfactants.
• Block copolymers based on quaternized 1,3-thiazole and 1,2,3-triazole side chain groups were synthesized by ATRP and CuAAC click chemistry reactions.
• Quaternized copolymers demonstrated a great antimicrobial activity, particularly against gram-positive bacteria, and non-toxic properties against RBCs with good selectivities.

New amphiphilic block copolymers with antimicrobial properties were obtained by atom transfer radical polymerization (ATRP) and copper catalyzed cycloaddition following two approaches, a simultaneous strategy or a two-step synthesis, which were proven to be very effective methods. These copolymers were subsequently quaternized using two alkyl chains, methyl and butyl, to amplify their antimicrobial properties and to investigate the effect of alkyl length. Antimicrobial experiments in solution were performed with three types of bacteria, two gram-positive and one gram-negative, and a fungus. Those copolymers quaternized with methyl iodide showed better selectivities on gram-positive bacteria, Staphylococcus aureus and Staphylococcus epidermidis, against red blood cells, demonstrating the importance of the quaternizing agent chosen. Once the solution studies were performed, we prepared poly(butyl methacrylate) latex particles functionalized with the antimicrobial copolymers by emulsion polymerization of butyl methacrylate using such copolymers as surfactants. The characterization by various techniques served to test their effectiveness as surfactants. Finally, films were prepared from these emulsions, and their antimicrobial activity was studied against the gram-positive bacteria. The results indicate that the antimicrobial efficiency of the films depends not only on the copolymer activity but also on other factors such as the surface segregation of the antimicrobial agent to the interface.

Figure optionsDownload as PowerPoint slide