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Single-wall carbon nanotubes (SWNTs) can be well-dispersed in water by wrapping with short segments of natural DNA from salmon sperm. We report here the isolated DNA-wrapped SWNT hybrids. Measurements were carried out using UV-vis-NIR, near-infrared photoluminescence (PL) spectrum and atomic force microscopy (AFM). A possible charge transport between SWNTs and salmon-DNA is discussed in terms of observed spectral shifts in the photoluminescence spectra.

This work demonstrates the assembly of TiO₂ nanoparticles with attached DNA oligonucleotides into a 3D mesh structure by allowing base pairing between oligonucleotides. A change of the ratio of DNA oligonucleotide molecules and TiO₂ nanoparticles regulates the size of the mesh as characterized by UV-visible light spectra, transmission electron microscopy (TEM) and atomic force microscopy (AFM) images. This type of 3D mesh, based on TiO₂-DNA oligonucleotide nanoconjugates, can be used for studies of nanoparticle assemblies in materials science, energy science related to dye-sensitized solar cells, environmental science as well as characterization of DNA interacting proteins in the field of molecular biology. As an example of one such assembly, proliferating cell nuclear antigen protein (PCNA) was cloned, its activity was verified, and the protein was purified, loaded onto double strand DNA oligonucleotide-TiO₂ nanoconjugates, and imaged by atomic force microscopy. This type of approach may be used to sample and perhaps quantify and/or extract specific cellular proteins from complex cellular protein mixtures based on their affinity for chosen DNA segments assembled into the 3D matrix.

In the field of structural DNA nanotechnology, researchers create artificial DNA sequences to self-assemble into target molecular superstructures and nanostructures. The well-understood Watson–Crick base-pairing rules are used to encode assembly instructions directly into the DNA molecules. A wide variety of complex nanostructures has been created using this method. DNA directed self-assembly is now being adapted for use in the nanofabrication of functional structures for use in electronics, photonics, and medical applications.

Various types of nanocrystals have extensively demonstrated significant advantages in magnetic, chemical, catalytic, and particularly optical properties. Still, some limitations prevent these properties from being utilized for improved biological imaging, therapeutics or micro/nano-optoelectronics. A recently emerging, facile approach employing oligonucleotide DNA or RNA for direct surface passivation of nanocrystals is showing promise to bridge the gap between functional potential and realization. Oligonucleotide capping can provide hydrophilic nature, target recognition capabilities, and enhanced cellular uptake for nanocrystals, with a simplified synthesis capable of both templating and functionalizing. We overview synthesis, properties, and applications of nucleic acid templated nanocrystals and contrast these with nanocrystals synthesized by more classical capping methods. Finally, we highlight areas of research in oligonucleotide templated nanocrystals that have been largely unexplored to date, where further investigations can provide many new insights.