In biomedical engineering, robotic implants provide new methods to restore and improve bodily function, and regenerate tissue. A significant challenge with the design of these devices is to safely actuate them for weeks or months, while they are residing in a patient's body. Magnetic, and other force-at-distance actuation methods, allow mechanisms to be controlled remotely and without contact or line of sight to the device. In this paper, we present a novel magnetic field driven wireless motor. The motor drives a robotic implant for the treatment of long gap esophageal atresia and short bowel syndrome. The motor is equipped with two oppositely oriented permanent magnets which experience forces in opposite directions when a magnetic field is applied tangential to the magnets' directions. The implant can produce a force of 2 N. It is demonstrated with an ex vivo porcine esophagus.

In this study, a novel robotic bioreactor is presented with capabilities of closed-loop control of force and displacement applied to a tissue scaffold and tissue scaffold stiffness calculation. These characteristics bring the potential of a robotic bioreactor that can optimize the mechanical properties of tissue constructs in order for them to match those of native tissues. Custom position and force control signals are designed to maintain a steady tensioning of the tissue scaffold while the latter one’s mechanical properties evolve in time. We propose a simple model to support the hypothesis that the stiffness of a cell-seeded scaffold increases over time, and thus force control signals need to be adjusted accordingly. The robotic bioreactor is able to measure the stiffness of a scaffold sample relatively accurately, with an average standard deviation of 0.2N/mm. The combination of accurate stiffness measurements and a closed-loop control system equips the robotic bioreactor with the fundamental requirements to achieve stiffness based force control in future in vitro experiments, and thus to a tissue-scaffold responsive technology for advanced tissue engineering.