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.
http://www.cbc.ca/radio/quirks/science-explains-when-to-visit-the-hospital-answer-emails-psychiatrist-s-new-warning-on-trump-s-mental-state-1.4480633/tiny-robots-inserted-in-pigs-are-making-tissue-grow-inside-the-body-1.4480643
Tiny robots inserted in pigs are making tissue grow inside the body