Figure 1

Schematics of the DNA-water interactions and mechanical analogy representation. Schematic cartoon of the hydrated ssDNA (a) and dsDNA (b). The number of water molecules depicted here is an estimation based on molecular dynamics simulations of hydrated layers. (c) Schematic cartoon of the mechanical analog of the DNA layer. Both the intermolecular interactions and the water molecules hold together the molecular components of the layer, giving as a result an effective spring constant. (d) Molecular dynamics simulations series for increasing molecular surface density from 3.1 × 10¹² molecules/cm² up to 2.5 × 10¹³ molecules/cm² for fully hydrated randomly attached ssDNA molecules on a non-interacting surface of 136 nm²; Na⁺ ions were introduced to neutralize the excess of charge. (e) MD simulation showing the thickness difference between a fully hydrated DNA layer and the same layer at dry, high vacuum conditions. Note the structural effect of water molecules in the individual ssDNA molecules, see Supplementary Information for further details.