Yu Bin, Davis Elisabeth M, Hodges Robert S, Irvin Randall T, Li D Y
Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada.
Nanotechnology. 2008 Aug 20;19(33):335101. doi: 10.1088/0957-4484/19/33/335101. Epub 2008 Jul 7.
Stainless steel is one of the most common metallic biomedical materials. For medical applications, its resistance to the adherence of biofilms is of importance to the elimination or minimization of bacterial infections. In this study, we demonstrate the effectiveness of a process combining surface nanocrystallization and thermal oxidation (or a recovery heat treatment in air) for reducing the biofilm's adherence to stainless steel. During this treatment, a target surface was sandblasted and the resultant dislocation cells in the surface layer were turned into nanosized grains by a subsequent recovery treatment in air. This process generated a more protective oxide film that blocked the electron exchange or reduced the surface activity more effectively. As a result, the biofilm's adherence to the treated surface was markedly minimized. A synthetic peptide was utilized as a substitute of biofilms to evaluate the adhesion between a treated steel surface and biofilms using an atomic force microscope (AFM) through measuring the adhesive force between the target surface and a peptide-coated AFM tip. It was shown that the adhesive force decreased with a decrease in the grain size of the steel. The corresponding surface electron work function (EWF) of the steel was also measured, which showed a trend of variation in EWF with the grain size, consistent with corresponding changes in the adhesive force.
不锈钢是最常见的金属生物医学材料之一。对于医学应用而言，其对生物膜附着的抗性对于消除细菌感染或使其最小化至关重要。在本研究中，我们展示了一种将表面纳米晶化与热氧化（或在空气中进行回复热处理）相结合的工艺在降低生物膜对不锈钢附着方面的有效性。在该处理过程中，对目标表面进行喷砂处理，随后在空气中进行回复处理，使表面层中产生的位错胞转变为纳米尺寸的晶粒。这一过程生成了更具保护性的氧化膜，能更有效地阻断电子交换或降低表面活性。结果，生物膜对处理过的表面的附着显著最小化。使用合成肽替代生物膜，通过原子力显微镜（AFM）测量目标表面与肽包被的AFM探针之间的粘附力，来评估处理过的钢表面与生物膜之间的粘附力。结果表明，粘附力随着钢晶粒尺寸的减小而降低。还测量了钢相应的表面电子功函数（EWF），其显示出EWF随晶粒尺寸的变化趋势，与粘附力的相应变化一致。
