Owing to their highly tunable structure and sequence-specific interactions, nucleic acid surface ligands can be used as programmable “bonds” to control the arrangement of nanoparticles into crystalline superlattices with precisely defined interparticle spacing, lattice symmetry, and crystal habit. Although significant advances have been made in the structural control of DNA-assembled colloidal crystals, less is known about the physical and chemical properties of the DNA bonds within these crystals and of their intrinsic ability to change in response to external stimuli. The use of external stimuli to post-synthetically tune DNA bond length and strength is particularly intriguing for the development of responsive colloidal crystals, where material properties can be changed on-demand. Here, we study the intrinsic responsiveness of nanoparticle-based DNA bonds and illustrate a new approach to the dynamic manipulation of superlattice structure. Remarkably, ethanol (EtOH) addition can be used to controllably tune DNA bond length and to increase bond stability, while retaining both long-range order and crystal habit. Interestingly, we find that these reversible structural changes occur in a cooperative fashion once a critical percentage of EtOH is reached and can be attributed to an EtOH-induced phase transition. These results provide a facile and robust approach to create stimuli-responsive nanoparticle superlattices, to access high volume fractions, and to improve thermal stability.

DNA-mediated assembly of stimuli-responsive colloidal crystals

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.