♪ MUSIC ♪ RASHID BASHIR: So this is actually a structure which has now two sets of muscle rings and one backbone. MILES O’BRIEN: These structures are tiny biological robots — or “BioBots” — and they move a bit like inchworms. RASHID BASHIR: What you see here is a real-time video of one of these BioBots that are about 8-10 millimeters long. MILES O’BRIEN: With support from the National Science Foundation, bioengineer Rashid Bashir and his team at the University of Illinois are building these BioBots, inspired by the many different ways creatures in the natural world have adapted to move around. RASHID BASHIR: Almost everything that we are trying to do in engineering is actually really in some ways trying to replicate the beauty and the intricacy and the complexity of what we find in nature. This actually mimics this muscle-tendon-bone complex, so this is kind of what gave us inspiration. MILES O’BRIEN: They start by using a laser to 3-D print skeletons — or scaffolds — made of polymers similar to those used in soft contact lenses. RASHID BASHIR: So wherever the laser is shining, the material is polymerizing and making that slightly harder scaffold. RITU RAMAN: The type of 3-D printing that we use is called stereolithography, and so we use light to do this building. These are our bio-bot skeletons. They’re basically a flexible beam connected by two stiffer pillars. When we engineer muscle tissue, it’s going to form around those pillars. MILES O’BRIEN: Next, they add muscle tissue engineered with mouse cells. CAROLINE CVETKOVIC: This is a fluorescent image showing the cells within our muscle strip. So what you see here is one long muscle fiber, very similar to what you would find in the human skeleton, and this is what we use in our muscle rings to power the bio-bot. MILES O’BRIEN: Earlier versions used cardiac cells, but the team found skeletal muscle cells gave them more control. They can make them contract, either with an electric pulse or with light. CAROLINE CVETKOVIC: As we increase the frequency with which we stimulate the BioBots we can actually get them to move faster. MILES O’BRIEN: In the future, they hope to make BioBots with neurons, as well, that will automatically react when they encounter certain substances like cancer cells or toxic chemicals. RASHID BASHIR: So the idea would be that the set of neurons is what is sensing a chemical and doing some processing and then instructing the mechanical device to move or not move. MILES O’BRIEN: Bashir sees many potential applications, like drug screening, toxic clean-up, even tiny clot-busting bots to treat people with cardiovascular disease. RASHID BASHIR: So we can think about implantable devices that are all biological that can be sensing and then releasing drugs. Then it’s kind of up to our imagination how these things could be used. So, medicine, in the environment. MILES O’BRIEN: Building bio-machines to inch our way toward healthier lives and a cleaner environment. That’s showing some muscle. For Science Nation, I’m Miles O’Brien.