title: Spontaneous and x-ray-triggered crystallization at long range in self-assembling filament networks.
abstract: We report here crystallization at long range in networks of like-charge supramolecular peptide filaments mediated by repulsive forces. The crystallization is spontaneous beyond a given concentration of the molecules that form the filaments but can be triggered by x-rays at lower concentrations. The crystalline domains formed by x-ray irradiation, with interfilament separations of up to 320 angstroms, can be stable for hours after the beam is turned off, and ions that screen charges on the filaments suppress ordering. We hypothesize that the stability of crystalline domains emerges from a balance of repulsive tensions linked to native or x-ray-induced charges and the mechanical compressive entrapment of filaments within a network. Similar phenomena may occur naturally in the cytoskeleton of cells and, if induced externally in biological or artificial systems, lead to possible biomedical and lithographic functions.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208, USA.
authors.forename: Honggang
authors.initials: H
authors.lastname: Cui
authors.forename: E Thomas
authors.initials: ET
authors.lastname: Pashuck
authors.forename: Yuri S
authors.initials: YS
authors.lastname: Velichko
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Weigand
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Cheetham
authors.forename: Christina J
authors.initials: CJ
authors.lastname: Newcomb
authors.forename: Samuel I
authors.initials: SI
authors.lastname: Stupp
mesh_terms: D055598:Chemical Phenomena; D020285:Cryoelectron Microscopy; D003460:Crystallization; D049329:Nanostructures / Q000648:ultrastructure; D010100:Oxygen; D010455:Peptides / Q000737:chemistry* / Q000528:radiation effects*; D011487:Protein Conformation; D053838:Scattering, Small Angle; D055672:Static Electricity; D013696:Temperature; D014961:X-Ray Diffraction; D014965:X-Rays
chemical_list: D010455:Peptides; D010100:Oxygen