Preparation and characterization of antibacterial microporous membranes fabricated by poly(AMS-co-DMAEMA)grafted polypropylene via melt-stretching method

Polypropylene microporous membranes are typical hydrophobic separation membranes, but the high hydrophobicity and lack of functionality easily cause bacterial adhesion, thus inducing membrane pollution. Poly（AMS-co-DMAEMA） （PAD） was designed and synthesized by copolymerization of a-methyl styrene （AMS） and functional monomer 2-（dimethylamino）ethyl methacrylate （DMAEMA）, and then grafted onto PP chains by melt blending. Microporous membranes of blended PP containing different contents of PAD are made by casting and stretching, and the polycation microporous membrane is then obtained via quaternization. The permeability and porosity of the microporous membrane achieve the best when the grafting efficiency reaches 42.16%, and the hydrophilicity of the microporous membrane is improved. The results show that the modified membranes fabricated in this method have good antibacterial properties.

A novel antibacterial biomaterial mesh coated by chitosan and tigecycline for pelvic floor repair and its biological performance

The biomaterials composed of mammalian extracellular matrix(ECM)have a great potential in pelvic floor tissue repair and functional reconstruction.However,bacterial infection does cause great damage to the repair function of biomaterials which is the major problem in clinical utilization.Therefore,the development of biological materials with antimicrobial effect is of great clinical significance for pelvic floor repair.Chitosan/tigecycline(CS/TGC)antibacterial biofilm was prepared by coating CS/TGC nanoparticles on mammalian-derived ECM.Infrared spectroscopy,scanning electron microscopy,bacteriostasis circle assay and static dialysis methods were used to characterize the membrane.MTS assay kit and DAPI fluorescence staining were used to evaluate cytotoxicity and cell adhesion.The biocompatibility was assessed by subabdominal implantation model in goats.Subcutaneous antimicrobial test in rabbit back was used to evaluate the antimicrobial and repairing effects on the infected wounds in vivo.Infrared spectroscopy showed that the composite coating had been successfully modified.The antibacterial membrane retained the main structure of ECM multilayer fibers.In vitro release of biomaterials showed sustained release and stability.In vivo studies showed that the antibacterial biological membrane had low cytotoxicity,fast degradation,good compatibility,anti-infection and excellent repair ability.

Mixed Matrix Membranes of Polysulfone/Polyimide Reinforced with Modified Zeolite Based Filler: Preparation, Properties and Application

In this work, polysulfone/polyimide（PSf/PI） mixed matrix membranes were fabricated by reinforcement of modified zeolite（MZ） particles through solution casting method for investigation of antibacterial activity against two gram negative bacteria（Salmonella typhi, Klebsella pneumonia） and two gram positive bacteria（Staphylococcus aureus, Bacillus subtilis）. The modified zeolite particles were incorporated to PSf and PI matrix and the influence of these particles on thermal, mechanical and structural properties was evaluated. The morphological evolution was investigated through scanning electron microscopy（SEM） and transmission electron microscopy（TEM） analysis, which revealed good compatibility between organic polymer matrix and inorganic filler. Mechanical stability was investigated by tensile testing while thermal analysis was evaluated by thermogravimetric analysis（TGA） and differential scanning calorimetry（DSC）. This revealed improvement in thermal properties with increasing filler concentration from 1 wt% to 10 wt%. Structural analysis was successfully done using X-ray diffraction analysis（XRD） and Fourier transform infrared（FTIR） spectroscopy. Solvent content of fabricated mixed matrix membranes was observed to decrease while moving from more hydrophilic to less hydrophilic solvent. However, addition of filler content enhanced the porosity of fabricated membranes. The synthesized mixed matrix membranes exhibited good antibacterial activity and the highest activity was shown by PSf/PI/MZ mixed matrix membrane. Therefore, the combination effect of PSf, PI and MZ sufficiently enhanced the antibacterial activity of mixed matrix membranes.