DNA based artificial nanostructures: Directed assembly of cellulose nanocrystals into advanced nanomaterials

The fabrication of nano-scale devices is a challenging, but potentially important, technology that has drawn a great deal of interest among researchers. Such nanoscale constructions utilizing a bottom-up approach for device building have many foreseeable applications in areas as diverse as miniaturized electronics, sensors, and biomedical devices.;One of the most chemically versatile, abundant and inexpensive nanoparticles available for nanodevice development is the cellulose nanocrystal (CNXL). CNXLs have drawn attention from researchers for their remarkable reinforcing abilities and excellent mechanical properties. CNXLs typically have high aspect ratios of around 20-50 (length/width), low density of around 1.6 g/cc, high stiffness (135 to 155 GPa) and strength (estimated at 7500 MPa).;Here we utilized CNXLs in a bottom-up hierarchical assembly to produce a macroscale material. The CNXLs were produced using an established acid hydrolysis protocol and were then oxidized using TEMPO-mediated carboxylation. Surface carboxylation of the C6 primary alcohol was confirmed by FTIR spectroscopy. Single stranded oligonucleotides with an amino modifier were successfully grafted on these carboxylated CNXLs. The molecular recognition ability of the oligomeric base pairs was then utilized by duplexing complementary oligonucleotides grafted onto separate CNXL populations. The resulting hybrid nanomaterials were characterized using dynamic light scattering and UV-Vis spectroscopy for its reversible thermoplastic processing attributes. Atomic force microscopy was used to characterize the morphology of the dried dispersion. To our knowledge, this is the first report of DNA being grafted to CNXLs and further being used to bond the CNXLs to each other.