细菌表面镀镍的透射电子显微镜与原子力显微镜表征

近年来微生物细胞由于尺寸小、几何外形标准多样和资源丰富等特点成为制备金属纳米结构或材料极具吸引力的生物模板。我们以典型的革兰氏阴性菌——大肠杆菌为模板通过无电子化学镀成功制备了具有标准杆状外形的表面镀镍的纳米金属材料，并利用原子力显微镜和透射电子显微镜对化学镀镍前后的大肠杆菌作了形貌学上的表征、测量与对比。结果显示，空白对照菌表面平整光滑并在云母基底表面表现出较显著的铺展效应；经过活化和化学镀镍后的菌细胞表面粗糙度明显增大，并在基本保持原有菌模板外形的基础上，其高宽比有所增大。超薄切片结果表明菌细胞表面的金属镍镀层分布均匀，其厚度处于纳米量级。

Recently bacterial cells have become attractive biological templates for the fabrication of metal nanostructures or nanomaterials due to their inherent small size, various standard geometrical shapes and abundant source. In this paper, nickel-coated bacterial cells (gram-negative bacteria of Escherichia coli) were fabricated via electroless chemical plating. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) characterization results reveal evident morphological difference between bacterial cells before and after deposition with nickel. The bare cells with smooth surface presented transverse outspreading effect at mica surface. Great changes took place in surface roughness for those bacterial cells after metallization. A large number of nickel nanoparticles were observed to be equably distributed at bacterial surface after activation and subsequent metallization. Furthermore, ultra thin section analytic results validated the presence and uniformity of thin nickel coating at bacterial surface after metallization.

TEM images of bare and metallized bacterial cells after Pd (II) activation and subsequent nickel deposition for 30s and 15min. The two histograms denote the size distribution of nickel particles from (b) and (c), respectively.

WANG Jing, HE ShiYing, XU LiNa and GU Ning,Transmission electron microscopy and atomic force microscopy characterization of nickel deposition on bacterial cells,Chinese Science Bulletin,2007,52,21:2919-2924.