Molecular self-assembly of DNA has been developed as an effective construction strategy for building complex materials. Among them, DNA hydrogels are known for their simple fabrication process and their tunable properties. In this study, we have engineered, built, and characterized a variety of pure DNA hydrogels using DNA tile-based crosslinkers and different sizes of linear DNA spacers, as well as DNA hydrogel/nanomaterial composites using DNA/nanomaterial conjugates with carbon nanotubes and gold nanoparticles as crosslinkers. We demonstrate the ability of this system to self-assemble into three-dimensional percolating networks when carbon nanotubes and gold nanoparticles are incorporated into the DNA hydrogel. These hydrogel composites showed interesting non-linear electrical properties. We also demonstrate the tuning of rheological properties of hydrogel-based composites using different types of crosslinkers and spacers. The viscoelasticity of DNA hydrogels is shown to dramatically increase by the use of a combination of interlocking DNA tiles and DNA/carbon nanotube crosslinkers. Finally, we present measurements and discuss electrically conductive nanomaterials for applications in nanoelectronics.
Mechanical and Electrical Properties of DNA Hydrogel-Based Composites Containing Self-Assembled Three-Dimensional Nanocircuits
