DNA01 is Plasmid pGem7zf+ (Promega), which is linearized with the Smal endonuclease. Linear DNA molecules (3000 b.p.) are deposited on freshly cleaved mica. Molecules are uniformly distributed over the surface with a molecular density of 0.5 – 7 molec./m². The typical DNA length is 1009 nm. Recommended humidity for obtaining a good image is 3-5.