Imaging of DNA molecules by atomic force microscope

This paper explores suitable conditions for the imaging of DNA molecules by atomic force microscope (AFM). As a typical biological macro-molecule, DNA with genetic information has attracted extensive attention, which is an important research subject in molecular biology and biomedicine. In this work, 3-Aminopropyl Triethyl Silane (APTES), Ni
²
+ and Mg
²
+ were used to modify the surface of mica substrate, and DNA molecules were adhered to the mica surface through the physical interaction of charges. The DNA molecules were imaged using an AFM under both air and liquid conditions. By analyzing the images of DNA molecules obtained in the experiments, it was found that the mica surface modified with Ni
²⁺
had the best imaging quality under the liquid condition. This work will be useful for the study of high quality AFM imaging of DNA molecules, and the manipulation of DNA molecules by AFM mechanical forces.