Colloidal Self-Assembly Via DNA Hybridization: Particle Heterogeneity and Nucleation Rates

The crystallization of colloids and nanocolloids due to the specific interaction of DNA hybridization is investigated. Ordered nanocomposites produced using the sequence-specific binding properties of DNA are expected to possess useful optical and electronic properties. We find that the crystal nucleation rate is highly sensitive to sphere-to-sphere variation in DNA density. Earlier experiments crystallizing micron sized colloids would not have nucleated were it not for such variation. Uniformly labeled smaller colloids have a finite classical nucleation rate; variation in labeling leads to a much higher nucleation and correspondingly smaller crystallites. This has been confirmed by simulation at finite rate which predicts that DNA labeled colloids at 980nm should not crystallize. This simulation also confirms that the nucleation barrier decreases with smaller particle size.