Self-Assembly of Giant Peptide Nanobelts

Abstract

Many alkylated peptide amphiphiles have been reported to self-assemble into cylindrical nanofibers with diameters on the order of a few nanometers and micrometer scale lengths; these nanostructures can be highly bioactive and are of great interest in many biomedical applications. We have discovered the sequences for these molecules that can eliminate all curvature from the nanostructures they form in water and generate completely flat nanobelts with giant dimensions relative to previously reported systems. The nanobelts have fairly monodisperse widths on the order of 150 nm and lengths of up to 0.1 millimeters. The sequences have an alternating sequence with hydrophobic and hydrophilic side chains and variations in monomer concentration generate a "broom" morphology with twisted ribbons that reveals the mechanism through which giant nanobelts form. Interestingly, a variation in pH generates reversibly periodic 2nm grooves on the surfaces of the nanobelts. With proper functionalization, these nanostructures offer a novel architecture to present epitopes to cells for therapeutic applications.One-dimensional (1D) nanostructures have attracted extensive research interest over the past decade due to the beneficial influence of their dimensionality on electronic and optical materials properties 1-4 and very recently bioactivity combined with ability to crosslink into gel networks. 5-11 Interesting examples include the vapor deposition synthesis of carbon nanotubes 1 , semiconductor nanowires 2, 3 and nanobelts 4 , and on the soft matter side the selfassembly of cylindrical micelles 12, 13 , ribbons 14 and peptide nanofibers 5-7, 10, 11 . The key factor in formation of these 1D nanostructures is control of preferential growth in only one dimension. While both cylinders (one-dimensional growth) and membranes (two-dimensional growth) have been frequently reported through self-assembly of molecular building units 12, 15-17 , flat 1D nanostructures, namely nanobelts, are less common because of the difficulty of maintaining two significantly different growth rates along two different dimensions.Peptides or proteins with one or more β-sheet strands exhibit the extraordinary ability to assemble into long, fibrillar nanostructures via intermolecular hydrogen bonding. 5,6,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Over the past few decades, extensive research efforts have been devoted to the structure and the formation mechanisms of amyloid fibers due to their links to neurodegenerative diseases 21-23 . In other work, there has been interest in 1D nanostructures formed by selfassembly of de novo designed peptides and peptidomimetics for their potential applications as biomaterials. 5,6,[24][25][26][27][28][29][30][31][37][38][39][40][41] Due to the intrinsic chirality of natural amino acids, the observed peptidic 1D nanostructures are often twisted or helical, and occasionally, they can *Corresponding author: E-mail: E-mail: s-stupp@northwestern.edu. Our previous work showed that a grea...

pH-triggered formation of nanoribbons from yeast-derived glycolipid biosurfactants

“…45,46 Even if predictions cannot be done, it has been empirically observed that fibers with nanoscale chirality can be formed in glycolipid-based systems if specific sugar-to-lipid linkers like phenyl, 15 phenylamide 47 or amidopyridine 48 groups are used over simple ether bonding. 15 The former enhance hydrogen bonding 47,49,35 or π−π stacking whereas the latest only promote the formation of micelles.…”

Fabrication of nanofibrous scaffolds for tissue engineering applications

“…Bundles of aligned PA nanofi bers were obtained, for example, by self-assembling PA within parallel channels (Hung and Stupp, 2007 ). By introducing hydrophilic amino acids in peptide segments, specifi c sequences of PA could self-assemble into nanobelts with fairly monodisperse widths in the order of 150 nm and lengths of up to 0.1 mm; these can be used as cell culture systems and drug delivery carriers (Cui et al , 2009 ). Nanofi brous scaffolds were also fabricated from self-assembly of β -sheet peptides containing phenylalanine for controlled release (Cui et al , 2009 ;Zhao et al , 2010 ).…”

“…By introducing hydrophilic amino acids in peptide segments, specifi c sequences of PA could self-assemble into nanobelts with fairly monodisperse widths in the order of 150 nm and lengths of up to 0.1 mm; these can be used as cell culture systems and drug delivery carriers (Cui et al , 2009 ). Nanofi brous scaffolds were also fabricated from self-assembly of β -sheet peptides containing phenylalanine for controlled release (Cui et al , 2009 ;Zhao et al , 2010 ). These studies proposed that the position of aromatic moieties is a signifi cant determinant for supramolecular self-assembling conformations.…”

Modelling Biological Polymeric Nanostructures in Physiological Fluids: Focus on Ribonucleic Acid Nanotubes

“…The self assembly of biological molecules such as DNA and RNA, and a range of different proteins can assist in creating the nanobelts in fluidic solutions which can be used for many therapeutic applications [1]. Due to the importance of therapeutic applications, several kinds of polygon-shaped self assemblies have been developed by using the deoxyribonucleic acid [2,3].…”