Adsorption and Self-Assembly of Oligodeoxynucleotides onto a Mica Surface

Atomic force microscopy has been used to study the specific structures of oligodeoxynucleotides (ODN) dried onto a freshly cleaved muscovite mica surface. The nucleotides have an important role in biology as the building blocks of the information coding DNA. To fulfill this task, the nucleotides must have specific self-assembling properties. The appearance of self-assembly was monitored as a function of different external factors, such as the concentration of the ODN, pH of the solution, and the composition of the surface material. At low ODN concentrations, around 20 nM, fiber-like formations appeared. At a rather high ODN concentration, around 400 nM, a network-like structure was seen. These formations appear only when the pH of the solution falls to between 3.3 and 4. Several surfaces were investigated, but the self-assembly of the ODN was observed only in the case of mica surfaces.