Spontaneous and X-ray-Triggered Crystallization at Long Range in Self-Assembling Filament Networks

• Published in: Science (American Association for the Advancement of Science) 2010-01, Vol.327 (5965), p.555-559
• Main Authors: Cui, Honggang, Pashuck, E. Thomas, Velichko, Yuri S, Weigand, Steven J, Cheetham, Andrew G, Newcomb, Christina J, Stupp, Samuel I
• Format: Article
• Language: English
• Subjects: Charge density; Chemical Phenomena; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Cryoelectron Microscopy; Crystallization; Dosage; Electrostatics; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General studies of phase transitions; Irradiation; Materials science; Methods of nanofabrication; Molecular biology; Molecules; Nanostructures - ultrastructure; Order-disorder and statistical mechanics of model systems; Organic compounds; Oxygen; Peptides; Peptides - chemistry; Peptides - radiation effects; Photons; Physics; Protein Conformation; Radiation dosage; Scattering, Small Angle; Self assembly; Solid-solid transitions; Specific phase transitions; Static Electricity; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Temperature; X ray observatories; X-Ray Diffraction; X-Rays
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1182340

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.