The Polymer-Induced Liquid Precursor Method Applied to DNA Nanostructures

Objectives: DNA Nanotechnology is a relatively new field, where synthetic DNA strands are designed to self-assemble into programmed architectures. DNA assemblies such as DNA nanotubes and 2D networks are of particular interest as tunable scaffolds in the design of functional hybrid materials. Here we investigate the ability of the polymer-induced liquid precursor (PILP) method, which has been used for intrafibrillar collagen mineralization, to promote mineralization in association with a DNA nanotube.

The two objectives of this project are: 1) to apply the PILP method with polyaspartic acid (PAsp) to a DNA nanotube; and 2) to covalently couple PAsp to a DNA nanotube. The hypothesis is that self-assembled DNA nanostructures decorated with PAsp will direct mineral formation.
Methods: Nanotubes were obtained by the self-assembly of synthetic DNA using a thermal annealing protocol. The DNA nanotubes were incubated with PAsp in Ca²⁺ - containing buffer, and the resulting assemblies were characterized by atomic force microscopy (AFM). Covalently associated PAsp-DNA conjugates were obtained via thiol-ene click chemistry.
Results: DNA nanotube formation occurred reproducibly in both Mg²⁺ - and Ca²⁺ - containing buffers. Adsorption of PAsp/Ca²⁺ spheres onto DNA nanotubes was apparent by AFM, and occurred at random locations. PAsp was also successfully conjugated to DNA via thiol-ene chemistry.
Conclusions: We show that: 1) DNA assembles into nanotubes that interact with PAsp in the PILP system; 2) DNA strands can be covalently coupled to PAsp with a goal towards precise patterning of PAsp for guided mineralization.