MNTL Hilights report web (Apr. 2016) - Page 12

PIONEERING BIOLOGICAL MACHINES Bioengineering Professor Rashid Bashir and Mechanical Science & Engineering Professor Taher Saif have demonstrated a class of tiny walking (less than a centimeter in size) bio-bots powered by muscle cells and controlled with electrical pulses. “Biological actuation driven by cells is a fundamental need for any kind of biological machine you want to build,” said Bashir, the Abel Bliss Professor and Bioengineering department head. “We’re trying to integrate these principles of engineering with biology in a way that can be used to design and develop biological machines and systems for environmental and medical applications.” Previously, Bashir and his collaborators, including Chemical & Biomolecular Engineering Associate Professor Hyunjoon Kong, demonstrated bio-bots that “walk” on their own, powered by beating heart cells from rats. However, heart cells constantly contract, denying researchers control over the bot’s motion. This makes it difficult to use heart cells to engineer a bio-bot that can be turned on and off, sped up or slowed down. The new bio-bots are powered by a strip of skeletal muscle cells, which are triggered by an electric pulse. This gives the researchers a simple way to control the bio-bots and opens the possibilities for other forward design principles, so engineers can customize bio-bots for specific applications. “Skeletal muscles cells are very attractive because you can pace them using external signals,” Bashir said. “For example, you would use skeletal muscle when designing a device that you wanted to start functioning when it senses a chemical or when it received a certain signal. To us, it’s part of a design toolbox. We want to have different options that could be used by engineers to design these things.” 12