DNA network structures induced by ferric ions on mica surfaces

This paper explores the changes of DNA network structures with different solution concentrations of DNAs and ferric ions by atomic force microscope (AFM). AFM is a powerful tool for both the observation and manipulation of biological molecules. DNA is an important life molecule to record the biological information and it is also a natural nano material which has great potential for the fabrication of molecular devices. The mica with a flat surface can be used as a substrate for observing DNA molecules, but the combination with DNA is not controllable, and the mica surface has to be modified. Here, we used ferric ions to induce DNA network structures and they were investigated by AFM. It was observed that when the concentration of DNA solution was low, there was no DNA network structures formed, and when the concentration of DNA solution was increased to 200-280ng/ul, DNA network structures were clearly formed.