Computational design of electrostatic potential to maximise or minimise adhesion to surfaces

The free energy of adsorption based on electrostatic interactions only has been optimised for glycine on a (111) diamond surface in continuum water to show maximum adhesion or maximum repulsion by adjusting the partial point charge distribution in the diamond surface model. It has been found that the free energy of adhesion is readily maximised by means of increasing the polarity of the electrostatic surface potential in a distinctive dipolar pattern. The maximum adhesion obtained in the present calculations was - 21.02 +/- 0.49 kJ mol(-1). The surface with the maximum repulsion. which would be of particular interest for designing novel surfaces with low protein adsorption, had a mostly uniform, slightly positive, surface electrostatic potential with a specific irregular pattern. The maximum free energy of repulsion achieved in the present simulations was 0.08 +/- 0.01 kJ mol(-1). These values suggest that most real surfaces are more likely to be overall attractive due to electrostatic interactions of the partial surface charges, and that the overall energy of repulsion, although theoretically possible, is likely to be small. (C) 2008 Elsevier B.V. All rights reserved.