Effects Of Ion And Chirality On The Antimicrobial Activities Of Poly(Ionic Liquid)s

Nowadays,microbial infection has become public health concern,which has attracted global attention to develop new drugs because antimicrobial resistance is increasing rapidly.The preparation of antibacterial materials and antibiotic with high efficiency,low toxicity and without drug resistance is urgent.As a novel kind of material,ionic liquids have been widely reported in antibacterial field.The antibacterial mechanism mainly involves electrostatic interactions between cationic moieties and the negatively charged bacterial cell membrane.And the hydrophobic segments can insert into the phospholipid bilayer lead to the membrane rupture and cell lysis.Poly(ionic liquid)s incorporate the special properties of ionic liquids into polymer chains and have been widely used in antibacterial field because of their tunable properties,including molecular weight,glass transition temperature,hydrophobic/hydrophilic balance,charge density and counter-ions.However,the effect of cations,configuration of antibacterial groups and chemical bond on antibacterial activities is rarely reported.Based on the designability of cations and anions,a series of ionic liquid monomers,poly(ionic liquid)s and polymeric membranes are synthesized by adjusting the structure of ionic liquids,such as cations,configuration and chemical bond.The relationship between structure and antibacterial activity is studied systematically.The main work includes are as follows:(1)The effects of cations of ionic liquids on antibacterial activities.Anionic ionic liquids and homopolymers with different cations,such as imidazolium,piperidinium,quaternary ammonium and phosphonium were synthesized for antibacterial applications.The effect of cationic structures on antibacterial activities is studied systematically by determination of minimum inhibitory concentration(MIC)and molecular dynamics simulations.The antibacterial activities of ionic liquids and homopolymers were both in the following order:phosphonium>imidazolium>piperidinium>quaternary ammonium.Moreover,the synthesized compounds displayed good hemocompatibility toward human red blood and may have potential application in healthcare field.(2)Antibacterial amino acid-based poly(ionic liquid)membranes:effects of chirality,chemical bonding type,and application for MRSA skin infections.A series of PIL membranes based on L/D-tryptophan and proline were prepared through ionic bond and covalent bond.The relationship between vitro antimicrobial performance and chemical structure were systematically researched.In addition,based on the antibacterial performance and biocompatibility in vitro,the therapeutic effects of PIL membranes in a methicillin-resistant S.aureus(MRSA)infected mouse model were investigated.The results indicated that both the ILs and PIL membranes containing D-enantiomeric amino acid groups exhibited higher antibacterial activities compared with those containing L-enantiomeric amino acids and the ionically-bonded PIL membranes showed higher antibacterial activities than the corresponding covalently-bonded polymeric membranes.Additionally,the amino acid-based PIL membranes accelerated the wound healing process,alleviated local tissue inflammation,and reduced the influence of bacteria on vital organs(liver and spleen)in MRSA infected mouse models,demonstrating the potential applications for antibacterial wound dressing.