Autonomous motors of a metal–organic framework powered by reorganization of self-assembled peptides at interfaces

• Published in: Nature materials 2012-12, Vol.11 (12), p.1081-1085
• Main Authors: Ikezoe, Yasuhiro, Washino, Gosuke, Uemura, Takashi, Kitagawa, Susumu, Matsui, Hiroshi
• Format: Article
• Language: English
• Subjects: 639/301/299/1013; 639/301/299/921; 639/301/54; 639/301/923/966; Autonomous; Bacteria; Biochemistry; Biomaterials; Biophysics; Chemical engineering; Condensed Matter Physics; Copper - chemistry; Direct power generation; Energy Transfer; Fuels; Kinetic energy; Kinetics; Materials Science; Metal-organic frameworks; Microtechnology; Motors; Nanopores; Nanostructure; Nanotechnology; Optical and Electronic Materials; Peptides; Peptides - chemistry; Phenylalanine - analogs & derivatives; Phenylalanine - chemistry; Pores; Self assembly; Swimming
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat3461

A variety of microsystems have been developed that harness energy and convert it to mechanical motion. Here we have developed new autonomous biochemical motors by integrating a metal–organic framework (MOF) and self-assembling peptides. The MOF is applied as an energy-storing cell that assembles peptides inside nanoscale pores of the coordination framework. The nature of peptides enables their assemblies to be reconfigured at the water/MOF interface, and thus converted to fuel energy. Reorganization of hydrophobic peptides can create a large surface-tension gradient around the MOF that can efficiently power its translational motion. As a comparison, the velocity normalized by volume for the diphenylalanine–MOF particle is faster and the kinetic energy per unit mass of fuel is more than twice as great as that for previous gel motor systems. This demonstration opens the route towards new applications of MOFs and reconfigurable molecular self-assembly, possibly evolving into a smart autonomous motor capable of mimicking swimming bacteria and, with integrated recognition units, harvesting target chemicals. Various artificial cells that can store molecules in cages are designed to generate mechanical motion by dissipating energy through chemical reactions or through the reorganization of molecules. A hybrid biomimetic motor system consisting of a metal–organic framework and diphenylanaline peptides is now designed to release guest molecules in the isotropic direction via a bond-breaking framework.