| Abstract
| - Biochip technology is based on the immobilization of biological macromolecules on the surface of electronicdevices. The biochemical properties of the immobilized molecules can be influenced to a large extent by theinteraction with the inorganic surface. The interaction of DNA with the surface of gold, a metal commonlyused in biochip technologies, is sequence dependent as the four nucleobases, adenine, thymine, cytosine, andguanine, interact to a different extent with the gold surface. The nature of nucleobase adsorption on the gold[111] surface has been investigated by performing density functional theory and post-Hartree−Fock calculations.It turns out that the interaction is dominated by dispersion forces and an appreciable degree of chemisorptionis observed for adenine only. A set of Lennard-Jones parameters that describe the interaction was derivedfrom the post-Hartree−Fock calculations. Classical molecular dynamics simulations of nucleobase monolayersbased on these parameters are in remarkable agreement with the experiment and show that the interaction ofthe nucleobases with the gold surface is strongly modulated by base−base interations and reaches a maximumwhen a full monolayer is formed.
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