Investigating Tissue Mechanics in vitro Using Untethered Soft Robotic Microdevices

Abstract

This paper presents the design, fabrication, and operation of a soft robotic compression device that is remotely powered by laser illumination. We combined the rapid and wireless response of hybrid nanomaterials with state-of-the-art microengineering techniques to develop machinery that can apply physiologically relevant mechanical loading. The passive hydrogel structures that constitute the compliant skeleton of the machines were fabricated using single-step in situ polymerization process and directly incorporated around the actuators without further assembly steps. Experimentally validated computational models guided the design of the compression mechanism. We incorporated a cantilever beam to the prototype for life-time monitoring of mechanical properties of cell clusters on optical microscopes. The mechanical and biochemical compatibility of the chosen materials with living cells together with the on-site manufacturing process enable seamless interfacing of soft robotic devices with biological specimen.

Actuated 3D microgels for single cell mechanobiology

“…amine groups) can be added to the surface of the nanoactuators during the synthesis process to facilitate chemical crosslinking. 26,27…”

“…amine groups) can be added to the surface of the nanoactuators during the synthesis process to facilitate chemical crosslinking. 26,27 Optically controlled nanoactuators were synthesized via seed-mediated gold nanorod growth and in situ free-radical polymerization of pNIPMAM, following a published protocol. 26 The gold nanorod core -pNIPMAM nanoparticles (Fig.…”

“…22 Moreover, they often require planar cell culture conditions and fall short in recreating biologically relevant 3D environments. The introduction of plasmonic and magnetic nanotransducers into highly deformable hydrogels enabled actuatable soft substrates [23][24][25] as well as 3D structures 26,27 that can be interfaced with living cells. The rotation of electroplated magnetic rods and laser-cut sheets using externally applied homogenous magnetic fields generated controllable torques within fibrillar matrices.…”