Scientists from France’s National Centre for Scientific Research (CNRS) have reported the development of an artificial muscle construct that uses thousands of individual molecular nano-machines to contract and extend a polymer chain over a length of 10 micrometers. The main component of the chain is rotaxane, a mechanically-interlocked molecular architecture that has been under investigation for use in molecular machine construction.
The compression and elongation of the chain is triggered by changing the pH of its environment, causing thousands of individual components to expand or contract by about one nanometer. The tiny combined motion of each molecular piece creates an overall displacement that is significant, pointing toward the creation of artificial muscles and nano-scale mechanical machines for medicine and other uses.
From the study abstract published in Angewandte Chemie International Edition:
Double-threaded rotaxanes can be linked to coordination units and polymerized in the presence of iron or zinc ions. pH modulation triggers cooperative contractions (or extensions) of the individual rotaxanes, thus resulting in an amplified motion of the muscle-like supramolecular chains with changes of their contour lengths of several micrometers (see picture).
Press release: Assembly of nano-machines mimics human muscle
Abstract in Angewandte Chemie International Edition: Muscle-like Supramolecular Polymers: Integrated Motion from Thousands of Molecular Machines