One of the main challenges of developing bottom-up designed materials is the issue of scaling their formation and shaping them into a desired morphology. A high degree of nanoscale control hinders the ability to form nanomaterials with predefined macroscale morphology. DNA nanotechnology allows accurate spatial control at the nanoscale, enabling intricate organization fabrication. Yet, structural arrangement at the macroscale remains a challenge.
The research group of scientists from the University of Columbia (USA) and the Bar-Ilan University (Israel) developed an assembly approach driven by acoustic waves in order to control the morphology of DNA-assembled materials at the scales from tens of microns to millimeters, thus complementing a nanoscale assembly regime offered by DNA-guided methods. Specifically, the researchers, led by HFSP Fellow Zohar Arnon, explored the use of standing surface acoustic waves (SSAW) to direct assembly and control the morphology of DNA origami-based crystal lattices. By controlling both acoustic forces and temperature, they investigated the assembly process at different scales by a combination of optical microscopy, small-angle x-ray scattering, and electron microscopy techniques.
Furthermore, the researchers studied the nucleation, crystal fusion and growth under different acoustic conditions. In a narrow pulse profile of the acoustic stimulation, the lattice formation is enhanced, and crystal size grows significantly larger. The developed approach allows to form macroscale nanomaterials with prescribed morphology, as defined by the acoustic field, while their nanoscale organization is programmed by DNA.
The experimental observations, recently published in Nature Communications, are supported by a model incorporating nucleation dynamics, diffusion-limited growth, and the effects of acoustic driving. The model provided valuable insights into the impact of acoustic waves on suppressed nucleation and crystal growth.
Overall, Zohar Arnon's study demonstrates the potential of acoustic waves as a complementary method for controlling the morphology of DNA-assembled nanomaterials at the macroscale. This approach expands the scope of DNA nanotechnology and paves the way for the fabrication of nanomaterials with tailored properties and functionalities for a wide range of applications.