A Temperature-dependent Dynamic Binding Protocol to study Folding of Colloidomers

Linear 'colloidomer' chains formed from droplets functionalized with mobile binders can fold into specific geometries, analogous to protein folding in biological phenomena. Recent experiments from the Brujic lab have demonstrated that incorporating secondary DNA interactions between droplets present in a colloidomer chain backbone can mediate the folding of these chains, via a suitable temperature protocol that takes into account two different melting temperatures (for the backbone and the secondary bonds) [McMullen et al. Nature (2022)]. In this work, we will present our coarse-grained (CG) model for colloidal particles with mobile linkers, which bind to each other via explicit formation and removal of bonded interactions. We have incorporated temperature-dependent binding/unbinding rates to mimic the cooperative melting behavior of the DNA used in experiment. This allows us to study folding pathways for our CG'ed colloidomer chains. We demonstrate that the relative yields of the foldamer geometries can be measured and also the kinetically accessible states can be determined from a folding energy landscape. Programming the order of secondary interactions can thus provide important design rules for generating foldamer structures which can be self-assembled further to form higher-dimensional supracolloidal materials.