Agitation of non-Brownian particles by active matrix of kinesin–microtubule motor proteins

In living organisms, many dynamic mechanisms are driven by motor proteins on a wide scale for tasks including the assembly of hierarchical structures at the nano to micrometre scales and macroscopic movements with hierarchical structures. Such complicated assemblies and sophisticated functions are intriguing for applications in nano and microengineering. Using motor proteins may enable multimolecular assembly in artificial systems by reproducing simple molecular movements using established methods such as motility assays of kinesin and microtubules. However, building a multimolecular system and selecting the target functions are key points to consider for potential applications. We use an active matrix consisting of crosslinked microtubules driven by kinesin to agitate microscopic objects that are not moved by thermal fluctuation, that is, non-Brownian particles. This method may contribute to enhance various self-assembly processes for larger objects. The resulting isotropic agitating properties are compared with those of other agitation methods based on external forces exerted by electric motors. The active matrix may provide a new type of mesoscopic scale actuator to perform stochastic mechanical agitation.