Published: Dec. 4, 2017 By

The day is coming when doctors-in-training can perfect certain medical practices on a robotic small intestine and test medical treatments on a human-made device vs. animals.

researchers with model of robotic small intestine

Mechanical engineering Associate Professor Mark Rentschler (far right) with graduate students (left to right) Levi Pearson, Greg Formosa and Kristin Calahan with an oversized version of a synthetic colon created as a senior design project. Rentschler is the lead scientist on a CU Boulder project to design a sophisticated robotic small intestine. (Photo by Patrick Campbell)

Mechanical engineering Associate Professor Mark Rentschler is leading the effort to develop an artificial, robotic small intestine for use in medical laboratories. The research is supported by a $1.25 million grant from the National Science Foundation.

While the small intestine is often thought of simply as a long coil of pink tubing inside the abdomen, the truth is much more complex. It is made up of ‘smooth muscle,’ a type of muscle that functions in the body automatically. Think of your esophagus—when swallowing food, an array of smooth muscles expand and contract one after the other to move the food from your mouth to the stomach. The small intestine works similarly, slowly advancing food and nutrients through your digestive tract.

“Our goal is to make something that functions the same way, where we have a tube of synthetic muscles that can sense each other, so when one contracts, the muscle adjacent to it can feel that change and know it needs to contract next,” Rentschler says.

The idea of a robotic small intestine may seem strange, as robotic devices are often thought of as being rigid and hard. However, Rentschler and an interdisciplinary team of CU Boulder researchers, including mechanical engineering Assistant Professor Christoph Keplinger, are challenging that perception. 

What you need to know
  • New device has implications for treating ailments, improving medical training.
  • Soft, flexible material has sensors, expands and contracts on demand.
  • Device has potential to accelerate biomedical research, reduce testing on animals.

"People usually imagine robots as metallic and clunky, but we’re now developing softer materials and stretchable electronic circuits,” Keplinger says.

The team will take advantage of an emerging robotics technology Keplinger created using a kind of flexible, rubber-like material lined with sensors. It can also expand and contract on demand. 

In addition to Rentschler and Keplinger, the research team includes computer science Associate Professor Nikolaus Correll, mechanical engineering Associate Professor J. Sean Humbert and a number of graduate and undergraduate students.

Ultimately, Rentschler envisions the artificial small intestine as a tool to accelerate medical research and evaluation of new colonoscopy and colorectal cancer screening devices and treatments, and simultaneously reduce the use of testing on animals. 

“Currently, this kind of work is often done with pigs, but their size is obviously not the same as humans, and they have some anatomical differences,” Rentschler says, “Being able to do testing with a robotic system that more closely matches human responses could help move things past animal testing and get to patients more quickly."

It would also be a strong training tool. While many colonoscopies are performed by gastroenterologists, they are also done by general surgeons and even primary care physicians. This system would offer a new way for doctors to refine their skill before treating patients. 

“The ability to develop a high-quality simulation is very attractive,” Rentschler says. “It would offer all sorts of options that currently don’t exist.”