Nature of Interaction between Semiconducting Nanostructures and Biomolecules: Chalcogenide QDs and BNNT with DNA Molecules

Interactions of DNA oligomers with two categories of semiconducting nanostructureschalcogenide quantum dots (QDs) and boron nitride nanotubes (BNNTs)owing to their widespread presence in bio-inspired processes are investigated using the first-principles density functional theory and continuum solvent model. The chalcogenide QDs interact strongly at their metal centers featuring electrostatic interaction with DNA oligomers at oxygen or nitrogen site, while BNNTs form covalent bonds with DNA oligomers at multiple surface sites. It is found that the different bonding nature leads to distinctly different response to the aqueous environment; the presence of solvent drastically reduces the binding strength of nucleobases with the QDs due to the strong electrostatic screening. This is not the case with BNNTs for which the covalent bonding is barely affected by the solvent. This study thus clearly shows how a solvent medium influences chemical interactions providing guidance for technological applications of bioconjugated systems.