Ghosh Soumadwip, Patel Nisheet, Chakrabarti Rajarshi
Department of Chemistry, Indian Institute of Technology , Powai, Mumbai, 40076, India.
J Phys Chem B. 2016 Jan 28;120(3):455-66. doi: 10.1021/acs.jpcb.5b12044. Epub 2016 Jan 12.
The hybrids of single-walled carbon nanotube (SWCNT) and single stranded DNA (ssDNA) are novel nanoscale materials having remarkable applications in nanotechnology. The absorption of nucleobases on the surface of a SWCNT depends strongly on the ionic strength of the medium. In this paper, using atomistic molecular dynamics we have shown that at low salt concentration ssDNA wraps on the surface of SWCNT through hydrophobic π-π stacking between the DNA bases and the sp(2)-hybridized carbon atoms of the carbon nanotube. At high salt concentration, however, the DNA molecule adopts a partially folded structure and the ssDNA-SWCNT wrapping gets weakened significantly due to the self-stacking of the DNA bases. Our study can find relevance in CNT mediated gene delivery processes where subsequent unwrapping of the gene from its carrier is anticipated across the cell membrane regulated by an existing salt concentration gradient.
单壁碳纳米管（SWCNT）与单链DNA（ssDNA）的杂化物是新型纳米材料，在纳米技术中有着显著应用。核碱基在SWCNT表面的吸附强烈依赖于介质的离子强度。在本文中，我们通过原子分子动力学表明，在低盐浓度下，ssDNA通过DNA碱基与碳纳米管的sp(2)杂化碳原子之间的疏水π-π堆积包裹在SWCNT表面。然而，在高盐浓度下，DNA分子呈现部分折叠结构，并且由于DNA碱基的自堆积，ssDNA-SWCNT包裹作用显著减弱。我们的研究与碳纳米管介导的基因传递过程相关，在该过程中，预计基因会在现有盐浓度梯度调节的细胞膜上从其载体上解包。
