Quirks & Quarks

Tiny robots inserted in pigs are making tissue grow inside the body

Robotic implants help stimulate cell proliferation and growth inside the body of living pigs.
Barnyard pigs weren't part of the experiment. (George Mortimer/CBC)

Robot implant encourages organ growth

A Canadian scientist working in the U.S. has constructed robotic implants that can stimulate the growth of tissue inside a living organism. The robotics in question are implants about the size of two thumbs pressed together; the tissue is any tubular organ inside the body, such as veins, intestines, arteries and esophagus. 

In this week's issue of the journal Science Robotics, Karl Price and his colleagues at Harvard Medical School and Boston Children's Hospital describe how they used the implant to lengthen the esophagus in five pigs while the animals were awake, moving and able to eat normally. Another three pigs acted as controls. 

Bowel syndrome

The aim is to make this standard practice for children, then move on to adults. Any tubular organs may need to be repaired, or regrown, for any number of reasons. A section can be missing because of a genetic defect, or a piece has had to be removed because of a blockage or infection, or in the case of the bowel, short bowel syndrome can be the problem. In the pig experiments, the chunk of esophagus that was missing was at least three centimetres.

One of the five pigs equipped with the esophagus-elongating robotic implant. (Dana Damian/Science Robotics)

Scientists at the University of Sheffield and Harvard used a robotic implant that includes various motors, sensors and electronics. About half is out of the body and the other half inside. The parts out of the body communicate to the implanted parts by way of an electric wire. The internal implanted parts includes a pair of rings that are placed around each end of the esophagus. 

As the robotics manipulates the two ends, the mechanical force stimulates the proliferation and growth of cells. This "traction force" can be set or adjusted according to the individual pig in this case. 

The robot senses how much force to use based on the length of gap and the size of the esophagus. The experiment proved that new growth was stimulated while the diameter of the organ stayed the same.

Scientists found the esophagus-growing robotic implant increased the length of the esophagus segment by 77 per cent on average. (Dana Damian/Science Robotics)

In about nine days, the gap between the two rings grew about 77 per cent. In humans, they think similar results could be achieved in one to four weeks.   

The advantages

There are many advantages to this technique. It is safer than doing an actual transplant. If it successfully applied in human patients then there is less chance, particularly in children, of them ripping sutures. It could also be applied to other organs, like skin or any other organ that may require being joined back together.