Importance of the DNA “Bond” in Programmable Nanoparticle Crystallization*

In this chapter, the authors observe the reorganization of nanoparticle superlattices using time-resolved synchrotron small-angle X-ray scattering in systems with different DNA sequences, salt concentrations, and densities of DNA linkers on the surface of the nanoparticles. The agreement between bulk crystallization and the behavior of free oligonucleotides may bear important consequences for constructing novel classes of crystals and incorporating new interparticle bonds in a rational manner. The authors evaluate the formation and reorganization of these crystals in a time-resolved manner using small-angle X-ray scattering to study how crystallization dynamics are affected by each design variable. They develop a predictive model that allows one to compare the range of temperatures over which crystallization will occur for different conditions. The authors explain reorganization kinetics based upon how the rates of hybridization and dehybridization change as a function of design variables including temperature, nucleobase sequence, oligonucleotide density, and solution ionic strength.