Diphenylalanine peptide nanotube: Charge transport, band gap and its relevance to potential biomedical applications

Peptide nanotubes (PNT) are emerging alternates frontier to carbon nanotubes (CNT). PNT's can be engineered by solid phase synthesis with desired properties. Chemically PNT's are reactive in sharp contrast to CNT's and hence require less site specific functionalization for nanotechnology applications. In this paper we are reporting the electronic coupling between the Phe-Phe dipeptide which is calculated using the density functional theory method. The calculations are performed for linear and cyclic structures of diphenylalanine peptide. The calculated electronic coupling is sensitive to the peptide electronic structure and shows a significant dependence for conformations. The band gaps obtained for PNT are compared with Boron Nitride and CNT. Peptide nanotubes (PNT) exhibit no cytotoxicity and hence offer tantalizing prospects in biomedical applications for example in drug delivery.