Walsh T R, Tomasio S M
Dept. of Chemistry and Centre for Scientific Computing, University of Warwick, Coventry, CV4 7AL, UK.
Mol Biosyst. 2010 Sep;6(9):1707-18. doi: 10.1039/c003417g. Epub 2010 Jun 10.
The number of possible applications that interface carbon nanotubes with biological systems is rapidly growing, and with these advances comes a need for characterisation of such interfaces. Molecular simulation is one such approach, and many recent examples exist where simulation has been used to investigate the atomic-scale details of the interface between biomolecules and carbon nanotubes (CNTs). However, these studies have been confined to the realm of pristine CNTs. Here, we build on our previous work and use molecular simulation to consider the adsorption on to defective CNTs of peptide sequences known to bind to the CNT surface [Wang et al., Nat. Mater., 2003, 2, 196]. Two types of idealised chemical defects are considered, along with two different distributions of these defects on the CNT surface. We find that the densely-packed defect distribution yields relatively little engagement with the peptides. Spreading the defects out along the nanotube increases the degree of contact with the peptide, without affecting the binding strength of the peptide-CNT interface in most cases. Both types of defect tend to act more as physical barriers to peptide mobility than as a source of attractive interactions. The resulting physical confinement of the peptide did not affect all sequences in the same way; two of the four sequences were found to be more sensitive to the presence of defects. This study has implications for the practical usage of CNTs in a wide range of biological contexts, where well-dispersed, functionalised nanotubes are required.
使碳纳米管与生物系统相连接的潜在应用数量正在迅速增长，随着这些进展，对这类界面进行表征的需求也随之而来。分子模拟就是这样一种方法，最近有许多例子表明，模拟已被用于研究生物分子与碳纳米管（CNT）之间界面的原子尺度细节。然而，这些研究仅限于原始碳纳米管领域。在此，我们基于之前的工作，利用分子模拟来考虑已知能与碳纳米管表面结合的肽序列在有缺陷的碳纳米管上的吸附情况[Wang等人，《自然·材料》，2003年，第2卷，第196页]。我们考虑了两种理想化的化学缺陷类型，以及这些缺陷在碳纳米管表面的两种不同分布情况。我们发现，紧密堆积的缺陷分布与肽的相互作用相对较少。沿着纳米管将缺陷分散开来会增加与肽的接触程度，在大多数情况下不会影响肽 - 碳纳米管界面的结合强度。这两种类型的缺陷往往更多地起到对肽移动性的物理屏障作用，而不是作为吸引相互作用的来源。肽由此产生的物理限制对所有序列的影响并不相同；发现四个序列中的两个对缺陷的存在更为敏感。这项研究对于碳纳米管在广泛生物环境中的实际应用具有启示意义，在这些应用中需要良好分散的功能化纳米管。
