Synthesis of Nucleobase-Functionalized Carbon Nanotubes and Their Hybridization with Single-Stranded DNA

• Published in: Chemistry, an Asian journal an Asian journal, 2014-12, Vol.9 (12), p.3408-3412
• Main Authors: Hwu, Jih Ru, Kapoor, Mohit, Li, Rou-Ying, Lin, Yung-Chieh, Horng, Jia-Cherng, Tsay, Shwu-Chen
• Format: Article
• Language: English
• Subjects: carbon nanotubes; Chemistry; Deoxyribonucleic acid; DNA; DNA delivery; DNA, Single-Stranded - chemistry; hybridization; Molecular Structure; Nanotechnology; Nanotubes; Nanotubes, Carbon - chemistry; single-stranded DNA; wrapping
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201402994

For the first time ssDNA (25‐aptamer of mixed dA, dT, dG, and dC) was wrapped around functionalized single‐walled carbon nanotubes (SWCNTs), whose external surfaces were attached to multiple triazole‐(ethylene glycol)‐dA ligands. This method of hybridization involved the formation of hydrogen bonds between dT of ssDNA and dA of functionalized SWCNTs. It deviates from the reported π–π stacking between the nucleobases of DNA and the external sidewalls of nanotubes. The structural properties of the functionalized SWCNTs and its ssDNA complex were characterized by spectroscopic (including CD and Raman), thermogravimetric, and microscopic (TEM) methods. The results thus obtained establish a new platform of DNA delivery by use of nanotubes as a new vehicle with great potential in biomedical applications and drug development. Wrapped up: Single‐stranded DNA (ssDNA) was hybridized with adenosine‐functionalized single‐walled carbon nanotubes (SWCNTs) and provided prominent CD peaks. Unlike the conventional very tight wrapping of nude SWCNTs by ssDNA through π–π stacking, the (poly dA)‐SWCNTs 1 A were bound to ssDNA by hydrogen bonds (see picture; purple dotted line = hydrophobic/hydrophilic spacer. The ssDNA can be liberated from the resultant hybrid at 50–55 °C.