Bioinspired Magnetite Crystallization Directed by Random Copolypeptides |
| |
Authors: | Jos J. M. Lenders Harshal R. Zope Ayana Yamagishi Paul H. H. Bomans Atsushi Arakaki Alexander Kros Gijsbertus de With Nico A. J. M. Sommerdijk |
| |
Affiliation: | 1. Laboratory of Materials and Interface Chemistry and Soft Matter CryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, MB, Eindhoven, The Netherlands;2. Institute for Complex Molecular Systems, Eindhoven University of Technology, MB, Eindhoven, The Netherlands;3. Leiden Institute of Chemistry, Leiden University, RA, Leiden, The Netherlands;4. Department of Biotechnology and Life Science, Faculty of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan |
| |
Abstract: | Control over magnetite (Fe3O4) formation is difficult to achieve in synthetic systems without using non‐aqueous media and high temperatures. In contrast, Nature employs often intrinsically disordered proteins to tightly tailor the size, shape, purity, and organization of the nanocrystals to optimize their magnetic properties. Inspired by such “flexible polyelectrolytes,” here random copolypeptides having different amino acid compositions are used as control agents in the bioinspired coprecipitation of magnetite through a ferrihydrite precursor, following a recently developed mineralization protocol. Importantly, the copolypeptide library is designed such that the amino acid composition can be optimized to simultaneously direct the size of the nanoparticles as well as their dispersibility in aqueous media in a one‐pot manner. Acidic amino acids are demonstrated to regulate the crystal size by delaying nucleation and reducing growth. Their relative content thus can be balanced to tune between the superparamagnetic and ferrimagnetic regimes, and high contents of negatively charged amino acids result in colloidal stabilization of superparamagnetic nanoparticles at high pH. Conversely, with positively charged lysine‐rich copolypeptides ferrimagnetic crystals are obtained which are stabilized at neutral pH and self‐organize in chains, as visualized by cryo‐transmission electron microscopy. Altogether, the presented findings give important insights for the future development of additive‐mediated nanomaterial syntheses. |
| |
Keywords: | biomimetic synthesis biomineralization Fe3O4
iron oxides magnetic nanoparticles |
|
|