(73i) Molecular Simulations of Biomimetic Assembly

Clarifying the driving mechanisms involved in various biological processes (i.e., protein aggregation, membrane fusion, etc.) has become one of the main goals in our scientific community. One of the promising directions for this task is by performing molecular simulations of analogous biomimetic assembly. In this presentation, I correspondingly discuss the two main research routes which I am pursuing: Particularly, together with my colleagues, I investigate hydration forces between colloids and phase transitions in polymers. First, in the colloidal project, we foremost resolve a paradox that has existed for a half of a century between numerical predictions and empirical measurements regarding the hydrophobic force: We specifically find a continuous transition between the association of small hydrophobes (below ~1 nm in size), which assemble entropically via a weak oscillatory force, and the association of large hydrophobes (above ~1 nm in size), which assemble enthalpically via a strong monotonic force; we explain this length-scale crossover in terms of the ability of a water solvent in forming a tetrahedral network around nonpolar solutes [1-2]. Besides, we also systematically transform these biomimetic colloids into hydrophiles, finding a multifaceted energy-scale crossover for the hydrophilic force [3]. Second, in the polymeric project, we examine a bead-spring chain that embodies a coil-crystal transition: Specifically via perturbation theory, we show that such a biomimetic polymer characterizes the universal kinetics associated with the force spectroscopy of various biological chains [4]. We continue by studying the influence of this coil-crystal transition of a single polymer on the corresponding aggregation propensity of many polymers. On a practical level, our molecular simulations for the biomimetic assembly of colloids and polymers can be of much aid in the design of pharmaceuticals.

[1] A. Chaimovich and M.S. Shell (PRE, 2013).
[2] A. Chaimovich and M.S. Shell (PRE, 2014).
[3] A. Chaimovich, R.R. Lele, M.S. Shell, J. Israelachvili, and M. Valtiner (In preparation).
[4] A. Chaimovich, C. Leitold, and C. Dellago (In preparation).