Interactions between crystals and organic molecules

The ability to control the binding of biological and organic molecules to a crystal surface is central to several research areas and technological applications, in particular biotechnology, catalysis, molecular microarrays, biosensors and environmental sciences. Furthermore, investigating the way mineral surfaces interact with biomolecules has fundamental implications considering that these substrates may have played an important role as catalysts for the polymerization of biomolecules in the prebiotic environment. In this contribution we present recent achievements in the field of the interaction between mineral surfaces and bio-organic molecules. For example, we found that DNA molecules have different binding affinities and assume different conformations when adsorbed to different layered silicate surfaces. We regularly observed on Chlorite isolated DNA molecules that became stretched bridging adjacent brucite-like surface regions. On these crystals the surface potential anisotropy is able to order and stretch the DNA filament thus inducing a natural change in its conformation. All the experimental results are in good agreement with simulations and mathematical modelling. The active stretching of DNA on Chlorite is a clear indication of the basic and technological potential carried by these minerals when used as substrates for biomolecules.