Shoji Takeuchi’s research while affiliated with Kanagawa Institute of Technology and other places

Integrating living tissues with robotic systems presents unique opportunities for developing next‐generation robots. This study addresses a critical challenge in skin‐covered biohybrid robots: maintaining a hydration supply to prevent rapid drying of living tissue in air‐exposed environments. A bilayered permeable subcutaneous support system, comprising a perforated skeletal layer and a permeable sponge‐like hydrogel layer made of polyvinyl alcohol (PVA), is proposed. The 3D‐printed skeletal layer, designed with dense perforations, provides structural strength for joint motion while allowing for fluid flow. The sponge‐like PVA hydrogel layer supports nutrient permeability and functions as a mechanical cushion beneath the dermal layer. The results demonstrate the sponge‐like PVA hydrogel's ability to retain moisture and allow the diffusion of nutrient molecules, effectively preventing dehydration of the cultured skin tissue. This approach offers a promising solution for enhancing the operational durability of skin‐covered robots, supporting their potential use in dynamic, real‐world applications.

In order to establish a detection and actuation system for 3D printed microfluidics, it is necessary to fabricate the 3D wiring microelectrodes. In this paper, a method is proposed that enables the fabrication of 3D wiring microelectrodes of several tens of micrometers in arbitrary designs. In the proposed method, attaching a lid made of polydimethylsiloxane (PDMS) on a 3D printed microfluidics, the introduction of low‐melting‐point alloy (LMA) into the 3D printed microchannel by the vacuum filling method is achieved. Theoretical models for predicting the LMA filling results and gained insights into the working principle of the proposed method have been established. Using this vacuum filling method, microelectrodes 50 µm width and height inside the 3D printed microchannels is successfully fabricated. Additionally, the design flexibility of the method is shown in the fabrication of 3D wiring microelectrodes in custom 3D shapes such as dead‐end electrodes, coil electrodes, and pillar electrodes. Furthermore, the sorting of live/dead spheroids by dielectrophoresis generated with the 3D wiring electrodes is demonstrated. It is believed that the proposed method will be highly beneficial in the field of microengineering, particularly in the context of 3D printing technology.

Biohybrid robots have attracted many researchers' attention due to their high flexibility, adaptation ability, and high output efficiency. Under electrical, optical, and neural stimulations, the biohybrid robot can achieve various movements. However, better understanding and more precise control of the biohybrid robot are strongly needed to establish an integrated autonomous robotic system. In this review, we outlined the ongoing techniques aiming for the contraction model and accurate control for the biohybrid robot. Computational modeling tools help to construct the bedrock of the contraction mechanism. Selective control, closed-loop control, and on-board control bring new perspectives to realize accurate control of the biohybrid robot. Additionally, applications of the biohybrid robot are given to indicate the future direction in this field.

Cultured muscle tissue serves as a power source in biohybrid robots that demonstrate diverse motions. However, current designs typically only drive simple substrates on a small scale, limiting flexibility and controllability. To address this, we proposed a biohybrid hand with multijointed fingers powered by multiple muscle tissue actuators (MuMuTAs), bundles of thin muscle tissues. The MuMuTA can provide linear actuation with high contractile force (~8 millinewtons) and high contractile length (~4 millimeters), which can be converted into the flexion of multijointed fingers by a cable-driven mechanism. We successfully powered the biohybrid hand achieving individual control of fingers and a variety of motions using different signaling controls. This study showcases the potential of MuMuTAs as a driving source for advanced biohybrid robotics.

Understanding the evolution of protocells, primitive compartments that distinguish self from nonself, is crucial for exploring the origin of life. Fatty acids and monoglycerides have been proposed as key components of protocell membranes due to their ability to self-assemble into bilayers and vesicles capable of nutrient exchange. In this study, we investigate the electrophysiological properties of planar bilayers composed of monoglyceride and fatty acid mixtures, using a droplet interface bilayer system. Three fatty acids with varying hydrocarbon chain lengths—oleic acid (C18), palmitoleic acid (C16), and myristoleic acid (C14)—in combination with monoolein (C18) are examined to evaluate the influence of chain length and composition on bilayer stability, thickness, and ion permeability. The results show that pure monoolein bilayers exhibit enhanced ion permeability compared to phospholipid bilayers, which are characteristic of modern cellular membranes. Furthermore, the incorporation of fatty acids into monoolein bilayers destabilizes the membrane structure and further increases ion permeability. We consider that this increased permeability is likely driven by three molecular characteristics. First, the wedge-like shape of monoolein may disrupt bilayer packing and induce transient pore formation. Second, the rapid flip-flop of fatty acids between bilayer leaflets likely facilitates ion transport. Third, the chain-length mismatch between monoolein and myristoleic acid further destabilizes the bilayer, promoting the formation of structural defects. These findings suggest that compositional motifs in monoglyceride-fatty acid bilayers may provide an alternative ion transport mechanism, such as the flip-flop of amphiphilic molecules, in early protocell membranes before the evolution of protein-based transporters.