Programming DNA-Mediated Colloidal Self-Assembly to Control 3D Binary Superlattice Formation

DNA-functionalized colloids are programmable materials that can self-assemble into a variety of crystal structures. Selective hybridization of conjugate base pairs of DNA molecules plays a fundamental role in tailoring the effective colloidal interactions as a useful tool to guide the formation of desired super-lattices. In binary systems, one promising advantage is the ability to independently tune the cross (A-B) and like (A-A or B-B) particle interactions via tethering two different mixtures of suitable strand sequences on different particles, known as multi-flavoring approach. This useful approach also allows controlling one of the like-like pair-interactions (A-A) independently of the other one (B-B). In this work, we conduct computer simulations to investigate the self-assembly of DNA-functionalized colloids into various 3-D binary crystals by programming cross- and like-particle interactions. The molecular dynamics simulations show that the variation of the strength of cross pair-potential relative to like interaction provides selectivity between body-centered cubic (BCC) and close-packed (FCC and HCP) structures. Moreover, changing the two like-interaction strengths (A-A and B-B) relative to one another, controls the composition of the crystals that form. In addition, the transformation kinetics and the thermodynamic stability of the formed structures will be studied.