Recognition of carbon nanotube chirality by phage display

We report a virus-based biological template, M13 bacteriophage, for selecting single-walled carbon nanotubes (SWCNTs), based on the premise that binding affinity between carbon nanotubes (CNTs) and peptides are sensitive to amino acid sequences. Bacteriophage pIII capsid fusion peptides, which have high binding affinity for CNTs, were identified through a directed evolution screening process by phage display technique. Specific binding consensus based on individual amino acid and amino acid grouping was obtained. Direct evidence of binding was provided by attachment of SWCNTs to selected bacteriophage-coated microspheres via an anti-M13 monoclonal antibody, seen by scanning electron microscopy. The selected peptides can be also used for dispersing and immobilizing CNTs. Quantitative analysis of the binding affinity is carried out using molecular dynamics simulations, aiming at understanding of the mechanisms of peptide-CNT binding and producing "designer" peptide of CNT surface recognition.