Synthesis And Properties Of Novel Polymeric Antimicrobial Agent Research

Antimicrobial polymers have been widely concerned for their effective and long-term antimicrobial ability. Most of the antimicrobial polymers studied were based on ammonium, phosphonium, pyridinium, organotin, or guanidine, whose applications are limited by their poor thermal stability. Meanwhile, the imidazolium may provide good stability due to its unique five-membered ring structure.Herein a seris of new imidazolium based antimicrobial polymers were synthesized, and the relationship between the thermal and antimicrobial properties and their structures was investigated. It was found that polymers based on imidazolium, especially those with BF4 and PF6 anion showed good thermal stability with the intial decomposition tempreature upto 350 o C, which was high enough for various applications. The study of the relationship between their structures and antimicrobial activities against E. coli and Staphylococcus aureus indicated that the polymer [poly(3 - dodecyl -1- vinylimidazolium bromide)] with the hydrophobic alkyl chain of 12 CH2 had the best antimicrobial properties, having the MIC values of 33μg/ml against E. coli and 47μg/ml against Staphylococcus aureus. In addition, the types of anions had great effect on the antibacterial with antimicrobial capability order of Br> BF4> PF6.The imidazolium based antimicrobial polymers were also modified to make antimicrobial drugs. To mimic the structure of antimicrobial peptides, amphiphilic cationic copolymers were designed and synthesized by copolymerization of antimicrobial monomers with hydrophilic PEG including PEG-co-poly(3-butyl-1-vinylimidazolium bromide) (PEG- co-3-P[BVIM][Br]), PEG-co–poly(3-hexyl-1-vinylimidazolium bromide) (PEG-co-3-P[HVIM][Br]), and PEG-co–poly(3-dodecyl-1-vinylimidazolium bromide) (PEG-co-3-P[DDVIM][Br]). The amphiphilic imidazolium cationic polymer self-assembled into nanoparticles in water, and the size of the nanoparticles decrease with the reductionof the hydrophobic alkyl chain length. The volume average hydrodynamic diameter of the nanoparticles made of PEG-co-3-P [BVIM] [Br], PEG-co-3-P[HVIM][Br], and PEG-co-3-P[DDVIM][Br] were 88 nm, 72nm and 19.3nm, respectively. Their blood compatibility, antimicrobial properties were investigagted, indicating that the hemolysis ability of antimicrobial copolymers decreased with the reduction in the alkyl length. with the HC50 for PEG-co-3-P[DDVIM][Br] , PEG-co-3-P[HVIM][Br], PEG-co-3-P [BVIM][Br] of 1μg/mL,5μg/mL and 100μg/mL. Antibacterial ability increased with the increase of the alkyl length. By comparing the HC50 values and MIC values, we find that PEG-co-3-P[BVIM][Br] are promising as antimicrobial drug wih the HC50 (100μg/ml)> MIC (90μg/ml),.Finially, since most of antimicrobial polyethylene (PE) and polypropylene (PP-R) pipes were made of silver antimicrobial agents with a risk of siliver pollution in water for life, the author in cooperation with Hangzhou Unicom Pipe Co., Ltd, developed antibacterial PE and PP-R pipes by adding antimicrobial polymers instead of silver antimicrobial agents and The health performance and mechanical properties of the antimicrobial PE and PP-R pipes reached industry standard, and their antibacterial rate reached 100%. The productions were successively industrialized with an annual production capacity of 12 million yuan.