Preparation And Characterization Of Antimicrobial Membranes Based On Polyhydroxybutyrate

Bacterial infection has been a serious problem in the field of biomaterial. In order to prepare biomaterials with superior bactericidal activity and analyze their properties, we chose biodegradable polyhydroxybutyrate(PHB) as the substrate. A series of antibacterial agents were designed and synthesized, and introduced into PHB to generate antibacterial biomaterials by physical mixture or grafting polymerization.In the first part, three quaternary ammonium salts were synthesized successfully and blended with PHB to produce antimicrobial membranes by solution casting and electrospinning, respectively. The synthesized quaternary ammonium salts were characterized by 1H NMR and FTIR. The mechanical properties and antibacterial efficacies of solution casting membranes and electrospinning fibrous membranes were investigated. Also, cytocompatibility were tested.In the second part, considering safety, antibacterial efficacy and regenerability of bactericidal materials, we synthesized a novel polymeric N-halamine containing quaternary ammonium salt(PHQS) to make antibacterial electrospun fibrous membranes by blending with PHB. The chemical structures of PHQS and intermediate products were characterized by NMR, FTIR and GPC. The obtained antibacterial fibrous membranes were characterized by SEM and TG. Also, the mechanical property, UV light stability, storage stability, antibacterial efficacy and cytocompatibility were evaluated.In the third part, another biodegradable material poly(butylene adipate-co-terephthalate)(PBAT) was introduced to improve toughness. Antibacterial agents mixed physically with fibers might suffer from annoying issues like leakage, aggregation and maldistribution, and the membranes could not inactivate all the bacteria. We synthesized N-halamine monomer containing quaternary ammonium salt(HQS), and grafted onto PHB/PBAT electrospun nanofibrous membranes to prepare antibacterial biomaterials. The chemical structures of HQS and intermediate products were determined by 1H NMR and FTIR. The obtained antibacterial samples were characterized by SEM, XPS and TG. Meanwhile, the mechanical property, UV light stability, storage stability, antibacterial efficacy and cytocompatibility were measured.The results demonstrated that the electrospun fibrous membranes showed more powerful antibacterial efficacy and toughness than solution casting membranes. The chlorinated PHB/PHQS membranes could inactivate 2.92 log of S. aureus and 1.00 log of E. coli within 30 min, respectively. The electron bean irradiation(EB) technique made antibacterial monomers bonded onto the chemically inertial materials PHB/PBAT as biocidal functional coatings become possible. The chlorinated PHB/PBAT-HQS samples provided potent antibacterial activities by inactivating about 6 log of Gram-positive S. aureus and Gram-negative E. coli O157:H7 within 5 min. The antibacterial biomaterials modified by PHQS and HQS showed excellent UV light and storage stability, regenerability, and good biocompatibility, which have great potential for food packaging and biomedical utilizations.