Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia.
Department of Medical Chemistry, Biochemistry and Clinical Chemistry, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia.
Int J Mol Sci. 2022 Mar 10;23(6):2983. doi: 10.3390/ijms23062983.
Bacterial contamination of the membranes used during guided bone regeneration directly influences the outcome of this procedure. In this study, we analyzed the early stages of bacterial adhesion on two commercial dense polytetrafluoroethylene (d-PTFE) membranes in order to identify microstructural features that led to different adhesion strengths. The microstructure was investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR). The surface properties were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM), and surface free energy (SFE) measurements. Bacterial properties were determined using the microbial adhesion to solvents (MATS) assay, and bacterial surface free energy (SFE) was measured spectrophotometrically. The adhesion of four species of oral bacteria (, , , and ) was studied on surfaces with or without the artificial saliva coating. The results indicated that the degree of crystallinity (78.6% vs. 34.2%, with average crystallite size 50.54 nm vs. 32.86 nm) is the principal feature promoting the adhesion strength, through lower nanoscale roughness and possibly higher surface stiffness. The spherical crystallites ("warts"), observed on the surface of the highly crystalline sample, were also identified as a contributor. All bacterial species adhered better to a highly crystalline membrane (around 1 logCFU/mL difference), both with and without artificial saliva coating. Our results show that the changes in polymer microstructure result in different antimicrobial properties even for chemically identical PTFE membranes.
细菌污染的膜用于引导骨再生直接影响这个过程的结果。在这项研究中，我们分析了细菌黏附在两个商业密集聚四氟乙烯（d-PTFE）膜的早期阶段，以确定导致不同黏附强度的微观结构特征。微观结构通过 X 射线衍射（XRD）、差示扫描量热法（DSC）和傅里叶变换红外光谱（FTIR）进行了研究。表面特性通过原子力显微镜（AFM）、扫描电子显微镜（SEM）和表面自由能（SFE）测量进行了分析。使用溶剂微生物附着（MATS）试验测定细菌特性，并用分光光度法测量细菌表面自由能（SFE）。研究了四种口腔细菌（，，，和）在有或没有人工唾液涂层的表面上的粘附。结果表明，结晶度（78.6%比 34.2%，平均晶粒尺寸 50.54nm 比 32.86nm）是促进黏附强度的主要特征，通过降低纳米级粗糙度和可能更高的表面硬度。在高结晶样品表面观察到的球形晶体（“疣”）也被认为是一个促成因素。所有细菌在有或没有人工唾液涂层的情况下，对高结晶膜的黏附性都更好（相差约 1 个对数 CFU/mL）。我们的结果表明，即使对于化学性质相同的 PTFE 膜，聚合物微观结构的变化也会导致不同的抗菌性能。
