2011-10-20 Bianca Mladek

From Ibivu

Coarse graining DNA-coated colloids

DNA strands which are chemically attached to the surface of colloids can work as "sticky ends" and allow colloids to bind to each other, thereby forming networks of auto-assembled particles. Studies of such DNA-coated colloids promise to offer insights into the necessary ingredients for gaining exquisite control over colloidal self-assembly. However, experimental exploration on self assembling ordered structures is still in its infancy, with the main hurdle being the lack of understanding of the thermodynamics and kinetics of DNA-mediated self-assembly. Detailed exploration of these structures via computer simulations on the other hand is hindered by the lack of adequate techniques and efficient coarse-grained models. In this presentation, we develop models of DNA-coated colloids at different levels of coarse-graining and at the experimentally relevant conditions. The different models are assessed for their validity and new simulation techniques developed to draw the phase diagram of such colloids. Finally, our findings (as e.g. melting temperature of the crystals or equilibrium lattice spacing) are compared to experimental results, showing agreement to within few percent and proving the strength of our coarse-grained models.