Hiroaki Onoe

Biohybrid robots are attracting attention as promising candidates to enhance robot applicability to studies on biological designs and in vitro construction of biological dynamic systems. Rapid progress in biohybrid robots with skeletal muscle tissues formed on a flexible substrate has enabled various types of locomotion powered by muscle tissue. However, it has been difficult to achieve high levels of both large and long-term actuations of the skeletal muscle tissues because of their spontaneous shrinkage through the course of the tissue culture. To overcome this limitation, we adapted the concept of biological systems and developed a biohybrid robot actuated by an antagonistic pair of skeletal muscle tissues. Our robot achieved large actuation (~90° of rotation of a joint) by selective contractions of the skeletal muscle tissues and a long lifetime (~1 week) by balancing tensions of the antagonistic tissues to prevent the spontaneous shrinkage. As a demonstration, we showed that our biohybrid robots allowed a pick-and-place manipulation of objects. This research may provide a platform to exceed the limitations of design in conventional biohybrid robots and replicate various lifelike movements.

This paper describes a method of generating three-dimensional (3D) cell-laden microstructures by applying the principle of origami folding technique and cell traction force (CTF). We harness the CTF as a biological driving force to fold the microstructures. Cells stretch and adhere across multiple microplates. Upon detaching the microplates from a substrate, CTF causes the plates to lift and fold according to a prescribed pattern. This self-folding technique using cells is highly biocompatible and does not involve special material requirements for the microplates and hinges to induce folding. We successfully produced various 3D cell-laden microstructures by just changing the geometry of the patterned 2D plates. We also achieved mass-production of the 3D cell-laden microstructures without causing damage to the cells. We believe that our methods will be useful for biotechnology applications that require analysis of cells in 3D configurations and for self-assembly of cell-based micro-medical devices.

Controlled synthesis of micro multi-compartmental particles using a centrifuge droplet shooting device (CDSD) is reported. Sodium alginate solutions introduced in a multi-barreled capillary form droplets at the capillary orifice under ultrahigh gravity and gelify in a CaCl(2) solution. The size, shape, and compartmentalization of the particles are controlled. Co-encapsulation of Jurkat cells and magnetic colloids into Janus particles is demonstrated. The Janus particles present sensitive reaction toward magnetic fields, while the viability of the encapsulated cells is 91%.