Abstract

3D Printing Bionic Devices

Michael McAlpine, Associate Professor, University of Minnesota

The ability to directly print biomedical devices on the body could benefit patient monitoring, wound treatment, and even allow for the possibility of human augmentation. This concept requires the 3D printer to adapt to the various translations, rotations, and deformations of the biological surface. Conventional 3D printing technologies typically rely on open-loop, calibrate-then-print operation procedures. An alternative approach is adaptive 3D printing, which is a closed-loop method that combines real-time feedback control and direct ink writing of functional materials in order to fabricate devices on moving freeform surfaces. Here we demonstrate that the changes of states in the 3D printing workspace in terms of the geometries and motions of target surfaces can be perceived by an integrated robotic system aided by computer vision. This allows us to directly 3D print a wireless antenna based on a novel silver ink a free-moving human hand, to power a skin-mounted LED. Moreover, we developed an in situ 3D printing system that estimates the motion and deformation of the target surface to adapt the toolpath in real time. With this printing system, a hydrogel-based sensor was printed on a porcine lung under respiration-induced deformation. The sensor was compliant to the tissue surface and provided continuous spatial mapping of deformation via electrical impedance tomography. This adaptive 3D printing approach may enhance robot-assisted medical treatments, enabling advanced medical treatments, as well as autonomous and direct printing of wearable electronics on and inside the body.