Scientists have created a new kind of miniature robot - also known as a bio-bot - that follows shining light. Powered by genetically engineered muscle cells designed to respond to light, researchers can use this ability to guide their motion, giving the new robots the potential to be used in various applications including diagnostics, medicine and sensing.
"Light is a noninvasive way to control these machines," said lead researcher, Rashid Bashir. "It gives us flexibility in the design and the motion. The bottom line of what we are trying to accomplish is the forward design of biological systems, and we think the light control is an important step toward that."
Bashir and his team used a technique called optogenetics to grow rings of muscle tissue from a mouse cell line. These muscle cells underwent the addition of a gene that made them respond to a certain wavelength of blue light by contracting and were subsequently looped around posts on flexible, 3-D printed backbones that range from approximately seven to two centimeters in length.
"The skeletal muscle rings we engineer are shaped like rings or rubber bands because we want them to be modular," said Ritu Raman, first author of the paper. "This means we can treat them as building blocks that can be combined with any 3-D printed skeleton to make bio-bots for a variety of different applications."
The researchers experimented with a variety of skeleton shapes and sizes in order to find the most effective configurations. The final product is a modular design that is not only less invasive than previous bio-bots that were activated with an electric field, but the thin muscle rings allow the diffusion of light and nutrients into the tissue.
"This is a much more flexible design," Bashir said. "With the rings, we can connect any two joints or hinges on the 3-D printed skeleton. We can have multiple legs and multiple rings. With the light, we can control which direction things move. People can now use this to build higher-order systems."
The findings were published in the March 14 issue of the Proceedings of the National Academy of Sciences.