Binding between DNA and Carbon Nanotubes Strongly Depends upon Sequence and Chirality

Certain single-stranded DNA (ssDNA) sequences are known to recognize their partner single-walled carbon nanotube (CNT). Here, we report on activation energies for the removal of several ssDNA sequences from a few CNT species by a surfactant molecule. We find that DNA sequences systematically have higher activation energy on their CNT recognition partner than on non-partner species. For example, the DNA sequence (TAT)(4) has much lower activation energy on the (9,1) CNT than on its partner (6,5) CNT, whereas the DNA sequence (CCA)(10) binds strongly to its partner (9,1) CNT compared to (6,5) CNT. The (6,5) and (9,1) CNTs have the same diameter but different electronic properties, suggesting that the activation energy difference is related to electronic properties. The activation energies of increasing lengths of closely related sequences from the 11-mer (TAT)(3)TA to the 21-mer (TAT)(7) on three different CNT species (9,1), (6,5), and (8,3) were measured. For the shorter sequences, the activation energy on the CNT varies periodically with the sequence.