戊二醛对原子力显微镜观测大肠杆菌的影响

The effect of glutaraldehyde on the imaging of Escherichia Coli using atomic force microscopy

戊二醛作为生物材料的固定剂,在原子力显微镜(AFM)制样中已广泛使用.虽然已有用戊二醛观测大肠杆菌的文献报道,但到目前为止,关于戊二醛在AFM观测大肠杆菌中的作用还缺乏系统研究.首先分析AFM扫描图像的假像,进而探讨戊二醛的浓度和固定时间对AFM图像质量和大肠杆菌表面形貌的影响.结果表明,戊二醛的浓度和固定时间对AFM图像的清晰度、大肠杆菌的微观结构以及细胞的三维尺寸都有着重要影响.在相同固定条件下所扫描的AFM图像与扫描电子显微镜(SEM)图像对比发现,两者的形貌相似,而AFM图像比SEM图像分辨率更高,在定量分析上也更有优势.

Glutaraldehyde has been used as a fixative of biomaterials in atomic force microscopy （AFM） extensively, and the literatures about imaging Escherichia coli using glutaraldehyde have already been reported. However, as far as we know, studies were rarely conducted to evaluate the effect of glutaraldehyde on imaging of Escherichia coli comprehensively. In this paper, the artifacts of AFM images were first analyzed, then the influence of concentration of glutaraldehyde and fixation time on the quality of AFM images and surface morphology of Escherichia coli were discussed. The results indicated that the concentration of glutaraldehyde and fixation time had significant influence on the AFM image definition, ultrastructure of the bacterial and 3D dimension of cell morphology. Comparison of AFM images and scanning electron microscope （SEM） images under the same fixative condition, both had the similar morphology, and AFM images possessed the higher resolution, and were in advantage of quantitative analysis.