Antimicrobial Expanded Polytetrafluoroethylene Film Prepared by 3-ray Radiation Induced Grafting of Poly（acrylic acid）

The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on ex- panded polytetrafluoroethylene （ePTFE） film was investigated. It was found that the degree of grafting （DG） of poly（acrylic acid） （PAA） can be controlled by the monomer concentration, absorbed dose, and dose rate under an optimal inhibitor concentration of [Fe2＋]=18 mmol/L. SEM observation showed that the macroporous structure in ePTFE films would be covered gradually with the increase of the DG of PAA. The prepared ePTFE-g-PAA film was im- mersed in a neutral silver nitrate solution to fabricate an ePTFE-g-PAA/Ag hybrid film after the addition of NaBH4 as a reduction agent of Ag＋ to Ag atom. SEM, XRD, and XPS results proved that Ag nanoparticles with a size of several tens of nanometers to 100 nanometers were in situ immobilized on ePTFE film. The loading capacity of Ag nanoparticles could be tuned by the DG of PAA, and determined by thermal gravimetric analysis. The quart- titative antibacterial activity of the obtained ePTFE-g-PAA/Ag hybrid films was measured using counting plate method. It can kill all the Escherichia coli in the suspension in 1 h. Moreover, this excellent antibacterial activity can last at least for 4 h. This work provides a facile and practical way to make ePTFE meet the demanding antimicrobial requirement in more and more practical application areas.

引导性组织再生术细菌感染的动物实验研究

目的检测引导性组织再生术(guided tissue regeneration,GTR)生物膜上和术区牙槽骨表面细菌种属、数量,分析菌群构成特点及异同点,为开发GTR抗菌性生物膜提供实验依据。方法 Beagle犬下颌前磨牙根分叉区做骨缺损形成二壁骨袋,行GTR术,术后8周2次取出GTR膨化聚四氟乙烯膜(expanded polytetrafluoroethylene,ePTFE膜),采集术区牙槽骨表面细菌标本。洗脱生物膜上和牙槽骨表面标本中细菌,进行培养,对每种培养基进行菌落计数,计算每种菌属构成比。结果 GTR术区牙槽骨表面和GTR生物膜上检测到的细菌包括:产黑色素菌、具核梭杆菌、放线菌、伴放线放线杆菌和变形链球菌,但是菌群特点并不相同,GTR术区牙槽骨区和生物膜上细菌构成比中,具核梭杆菌构成比均最大。结论应同时检测GTR术区牙槽骨区细菌种类,本研究中GTR术区牙槽骨表面和生物膜上细菌包括:革兰阳性菌、革兰阴性菌、厌氧菌和微需氧菌,提示抗菌性生物膜上的抗菌剂的选择应该为多种抗菌剂联合应用。