This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers have created a material that manufactures the proteins responsible for cell movement, without needing intact living cells. By embedding cell-free gene expression into a thin sheet of protein filaments, they were able to make the material wrinkle, rise into blister-like shapes and break into bundles that flow around one another.
The instructions driving these transformations are built into the material itself—in DNA. Changing the genetic program made the filaments sustain flowing motion, stop after a burst of activity or repeatedly speed up and slow down. The study, published in Nature Materials, demonstrates mechanical behavior that is "genetically programmed and executed autonomously," as the authors describe it.
Once assembled, the material can change its activity without researchers intervening at each step. Combining these instructions with patterned boundaries offers a path toward engineering genetically encoded mechanochemical materials and autonomous active systems. Scientists have previously made moving materials from cellular components.
In a 2012 study, for example, molecular motors drove protein filaments into chaotic flows. The current work gives such a material an internal system for producing and regulating its motors instead of using an external force. The team, including Rochelle Silverman and Alexandra Tayar of Israel's Weizmann Institute of Science and collaborators at the University of Minnesota, began with microtubules—microscopic protein filaments that help form the internal scaffolding of cells.
They assembled the filaments into a dense sheet in a well about 3.3 millimeters across, then supplied DNA and a mixture containing the cellular machinery and ingredients needed to make proteins. The DNA encoded kinesin, a motor protein that consumes chemical fuel to move along microtubules. As newly made motors accumulated and clustered together, they connected neighboring filaments and slid them past one another.
Growing internal forces made the sheet buckle. Its raised structures eventually fractured, leaving bundles in swirling, irregular motion. Adding more motor-coding DNA generally brought the action forward.
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