Improved electrical conductance through self-assembly of bioinspired peptides into nanoscale fibers Rhiannon C.G. Creasey * , Yoshitaka Shingaya, Tomonobu Nakayama ** International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan highlights graphical abstract  We designed a novel peptide sequence from natural amino acids which forms nanofibers in water.  The nanofibers were investigated by AFM, fluorescence and CD spectroscopy.  A film of self-assembled peptide shows conductivity in air and vacuum.  We propose that stacking of phenyl- alanine between peptides leads to conductivity. article info Article history: Received 26 December 2014 Received in revised form 19 February 2015 Accepted 23 March 2015 Available online xxx Keywords: Biomaterials Atomic force microscopy (AFM) Electrical conductivity Nanostructures abstract We investigated the electrical conductance of films consisting of bio-inspired peptide molecules and of their extended form, self-assembled nanoscale fibers. Here, the entirely natural and novel peptide sequence, GFPRFAGFP, was designed based on naturally occurring fibrous proteins. To attain electrical conductance, we implemented phenylalanine residues in the sequence such that the aromatic rings are present along face of the molecule. We confirmed self-assembly of nanoscale fibers in pure water after incubating the peptides at 37  C by AFM. The morphology and conformation of the incubated peptide fibers were studied using AFM, fluorescence spectroscopy and circular dichroism spectroscopy. It was shown that very thin fibers with a single-molecule-level diameter form. The helical feature of the peptide backbone and enhanced stacking of aromatic residues were also investigated. This aromatic stacking is important to our electrical measurements as, even in vacuum environment, films of non-incubated GFPRFAGFP sometimes show apparent conductance while those containing self-assembled nanoscale fibers show stable and improved conductance. We propose that this effect may be due to extended stacking of aromatic residues providing p e p conjugation along the fiber. © 2015 Elsevier B.V. All rights reserved. 1. Introduction In the last decade, increasing needs for electrically conductive nanomaterials have been emerging for use in electronic devices [1], medical [2,3], and sensing [4,5] applications, among others. In particular, one dimensional conductive nanostructures are essen- tial for the construction of nanodevices [5e7]. One method of * Corresponding author. Present address: School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, United Kingdom. ** Corresponding author. E-mail addresses: Rhiannon.Creasey@nottingham.ac.uk (R.C.G. Creasey), Nakayama.Tomonobu@nims.go.jp (T. Nakayama). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys http://dx.doi.org/10.1016/j.matchemphys.2015.03.034 0254-0584/© 2015 Elsevier B.V. All rights reserved. Materials Chemistry and Physics xxx (2015) 1e8 Please cite this article in press as: R.C.G. Creasey, et al., Improved electrical conductance through self-assembly of bioinspired peptides into nanoscale fibers, Materials Chemistry and Physics (2015), http://dx.doi.org/10.1016/j.matchemphys.2015.03.034