Supercoiled circular plasmide DNA (pEGFP, 3.4 kb. p.) on mica. To bind molecules to mica substrate buffer solution contains 5 mM HEPES, 10 mM MgCl2 was used. Spatial pattern of the molecule is typical for low salt buffers.The image was obtained in semicontact mode in ethanol. Triangular silicon nitride probe with spring constant 0.5 N/m was used.
The sample was kindly given by I. I. Agapov and E.A. Tonevitsky, Institute for transplantation and artificial organs, Moscow, Russia.