通常，表面粗糙度的增加会诱导细菌的吸附，但是在含有纳米银的多孔聚合物表面上，细菌的吸附得到了有效的抑制。我们在试验中采用了金葡菌和大肠杆菌，对这两种不同种属和形状的细菌，Ag/PLLA多孔结构都显示了很好的抗粘附能力，对大肠杆菌的效应尤为显著。多孔结构对纳米银的抗菌效率有较大的提升作用。多孔结构增大了纳米银与水环境的接触面积，从而促进了银离子的释放，同时这种孔洞结构有利于银离子在材料表面的富集，防止其扩散或被流动的水环境带走，因此将对吸附在表面的细菌具有更强的杀伤效率。同时细胞毒性试验表明，Ag/PLLA多孔结构的表面并不会对细胞产生毒性，是一种安全的生物材料。
通过BF法制备的纳米银/聚合物多孔膜，提供了一种简单，易控制的方法，改变生物材料的表面性质，使材料成为具有利于细胞生长，并兼具抗菌性的多功能材料。通过BF法和纳米银的界面效应，可以调控该复合膜的多种表面性质，如多孔膜的孔洞大小，膜的厚度，也可以通过调控纳米银的表面性质得到多功能的材料表面。
Xiaoli Jiang, Tianzhu Zhang, Shiying He, Jingjing Ling, Ning Gu, Yu Zhang, Xuefeng Zhou, Xing Wang, and Lu Cheng.Bacterial Adhesion on Honeycomb-Structured Poly(L-Lactic Acid) Surface with Ag Nanoparticles.J. Biomed. Nanotechnol. 8, 791-799 (2012)
Fig. 1. (A) TEM image of Ag nanoparticles-impregnated PLLA and (inset) the size distribution of Ag nanoparticles. (B) Darkfield microscopy image of flat Ag/PLLA film cast at 30% RH. The plasmon resonant colors indicate the presence of Ag nanoparticles. (C) Optical microscope image and (D) darkfield image of honeycomb-patterned Ag/PLLA film cast at 90% RH.
Fig. 3. Amount of Ag+ released from flat and honeycomb-structured Ag/PLLA films in deionized water as a function of time.
Fig. 4. Histograms of bacterial adhesion degree for PLLA and Ag/PLLA films after 24 h incubation against two microorganisms.
Fig. 5. SEM images of (A, B, C) S. aureus and (D, E, F) E. coli adhesion on (A, D) flat PLLA films, (B, E) flat Ag/PLLA films, and (C, F) honeycomb-structured Ag/PLLA films after 24 h of culture, respectively.
Fig. 6. Cross-sectional schematic diagram of the adhesion behavior of bacteria on (A) flat or (B) honeycomb-structured Ag/PLLA films. Cross-sectional SEM images of S. aureus adhesion on (C) flat or (D) honeycomb-structured Ag/PLLA films after 24 h of culture.
