| Exploition of novel antibacterial agents that contact non-specifically with bacteria is one of the solutions to solve the problem of bacterial infection.Guanidine-based antibacterial polymers having prolonged,broad-spectrum and high-efficiency antibacterial properties,no eukaryotic cytotoxicity,and difficulty in being resistant by bacteria have been widely studied and applied in the antibacterial field.The main chain type guanidine-based antibacterial polymers,which were mainly composed of polyhexamethylene guanidine hydrochloride(PHMG),have been widely studied and applied.The side chain type guanidine-based polymers can be achieved by the conversion of guanidine in the side chain of amine-based polymers or by the direct polymerization of guanidine-functionalized monomers.The surface graft type guanidine-based antibacterial polymers have been put to some practical applications.In this paper,a novel guanidine-functionalized monomer,methacryl hydrazide hydrochloride(MAGH),was synthesized by Schotten-Baumann amidation.Then a series of MAGH homopolymers(PMAGH)with controlled molecular weight(Mn=6.5-47.3 kg mol-1)and narrow molecular weight distribution(D=1.21-1.64)were synthesized via reversible addition-fragmentation chain transfer(RAFT)polymerization using S,S’-bis(a,a’-dimethyl-a"-acetic acid)trithiocarbonate(BDATC)as the chain transfer agent.The antibacterial experiment by dilution method showed that the minimum inhibitory concentration(MIC)of PMAGH against Escherichia coli(E.coli)was 113-225 μg mL-1,and the MIC against Bacillus subtilis(B.subtilis)was 450 mL-1.Novel amphiphilic poly(methacryl guanidine hydrochloride)-block-polystyrene-block-poly(methacryl guanidine hydrochloride)(PMAGH-b-PS-b-PMAGH)ABA triblock copolymers with a controlled molecular weight(Mn=10.9-46.4 kg mol-1)and composition(molar content of MAGH=9.9%-48.1%)were synthesized via RAFT polymerization of MAGH and styrene,using BDATC as the initial chain transfer agent.Highly ordered honeycomb films of PMAGH-b-PS-b-PMAGH were fabricated via a facile and versatile static breath-figure process at 40℃ and 95%relative humidity with 10 mg mol-1 chloroform solution.The phenomenon that the hydrophobic polystyrene block is away from the pores,and the hydrophilic guanidine-based blocks move toward the edge of the pores induced by water droplets in the pores during the self-assembly process of the polymers was found.The honeycomb films of PMAGH-b-PS-b-PMAGH inhibited 61%of E.coli and 92%of B.subtilis.0.2 g mL-1 of PMAGH-b-PS-b-PMAGH chloroform solution was fabricated into uniform ribbon-like micro fiber film by electrospinning process at voltage of 30 kV and feeding rate of 20 μL min-1.Parameters affecting morphology and size of fiber including concentration,voltage,and feeding rate were systematically investigated during electrospinning process.The mechanism that positively charged polymers determine the ribbon-like morphology of microfibers was proposed and verified.The antibacterial experiment by dynamic contact method showed that the PMAGH-b-PS-b-PMAGH microfiber film could inhibit 96%E.coli and 92%B.Subtilis. |
