Probing interfacial equilibration in microsphere crystals formed by DNA-directed assembly.
DNA is the premier material for directing nanoscale self-assembly, having been used to produce many complex forms. Recently, DNA has been used to direct colloids and nanoparticles into novel crystalline structures, providing a potential route to fabricating meta-materials with unique optical properties. Although theory has sought the crystal phases that minimize total free energy, kinetic barriers remain essentially unstudied. Here we study interfacial equilibration in a DNA-directed microsphere self-assembly system and carry out corresponding detailed simulations. We introduce a single-nucleotide difference in the DNA strands on two mixed microsphere species, which generates a free-energy penalty for inserting 'impurity' spheres into a 'host' sphere crystal, resulting in a reproducible segregation coefficient. Comparison with simulation reveals that, under our experimental conditions, particles can equilibrate only with a few nearest neighbours before burial by the growth front, posing a potential impediment to the growth of complex structures.
Kim
Anthony J
AJ
Department of Chemical and Biomolecular Engineering, The University of Pennsylvania, 220 S. 33rd St., Philadelphia, Pennsylvania 19104, USA.
Scarlett
Raynaldo
R
Biancaniello
Paul L
PL
Sinno
Talid
T
Crocker
John C
JC
D002616:Chemical Engineering / Q000379:methods; D003460:Crystallization; D004247:DNA / Q000737:chemistry*; D008863:Microspheres; D049329:Nanostructures; D013499:Surface Properties; D013816:Thermodynamics
D004247:DNA