|13 February 2017|

USA

Researchers based at an American university are sharing their recipe for building bio-bots.

The University of Illinois at Urbana-Champaign team has spent years developing the bio-bots, which are powered by muscle cells and controlled with electrical and optical pulses.

“The protocol teaches every step of building a bio-bot, from 3D printing the skeleton to tissue engineering the skeletal muscle actuator, including manufacturers and part numbers for every single thing we use in the lab,” explained Ritu Raman, now a postdoctoral fellow in the Department of Bioengineering and first author of the paper, “A modular approach to the design, fabrication, and characterization of muscle-powered biological machines.

“This protocol is essentially intended to be a one-stop reference for any scientist around the world who wants to replicate the results we showed in our PNAS 2016 and PNAS 2014 papers, and give them a framework for building their own bio-bots for a variety of applications.

Rashid Bashir, a Grainger Distinguished Chair in Engineering and head of the Department of Bioengineering at Illinois, said the protocol means “others can easily duplicate the work and help to further permeate the idea of ‘building with biology’–so that other researchers and educators can have the tools and the knowledge to build these bio-hybrid systems and attempt to address challenges in health, medicine, and environment that we face as a society.”

The team has pioneered the development of the bio-bots, which are less than a centimeter in size, made of flexible 3D printed hydrogels and living cells.

Raman added: “The 3D printing revolution has given us the tools required to ‘build with biology’ in this way. We re-designed the 3D-printed injection mold to produce skeletal muscle ‘rings’ that could be manually transferred to any of a wide variety of bio-bot skeletons. These rings were shown to produce passive and active tension forces similar to those generated by muscle strips.

“Using optogenetics techniques, we worked with collaborators at MIT to genetically engineer a light-responsive skeletal muscle cell line that could be stimulated to contract by pulses of 470-nm blue light. The resultant optogenetic muscle rings were coupled to multi-legged bio-bot skeletons with symmetric geometric designs. Localized stimulation of contraction, rendered possible by the greater spatiotemporal control of light stimuli over electrical stimuli, was used to drive directional locomotion and 2D rotational steering.”