Modulating Homogeneous Crystal Nucleation in DNA-Coated Colloids

While DNA-coated particles have been reported to form a variety of different colloidal crystalline structures, the factors determining nucleation (or its absence) remain poorly understood.   As with other colloidal crystals, we find that homogeneous nucleation rates depends on the ratio of the particle radius to the range of the DNA-induced attractive interactions.  Unexpectedly, we find that particle-to-particle variations in DNA content, which give rise to comparable heterogeneity in interaction strength, significantly accelerate homogeneous nucleation rates in some crystals.  This is demonstrated in detailed Langevin Dynamics simulations and experiment.  The physical determinants of such DNA content variations, and how they can be engineered to modulate nucleation, will be discussed.