Development and characterization of muscle-based actuators for self-stabilizing swimming biorobots

Abstract

Biorobots that harness the power generated by living muscle cells have recently gained interest as an alternative to traditional mechanical robots. However, robust and reliable operation of these biorobots still remains a challenge. Toward this end, we developed a self-stabilizing swimming biorobot that can maintain its submersion depth, pitch, and roll without external intervention. The biorobot developed in this study utilized a fin-based propulsion mechanism. It consisted of a base made from two composite PDMS materials and a thin PDMS cantilever seeded with a confluent layer of heart muscle cells. The characterization of the heart muscle cell sheet revealed the gradual increase of the dynamic contraction force and the static cell traction force, which was accompanied by a linear increase in the expression levels of contractile and cytoskeletal proteins. In the design of the biorobot, instead of relying only on the geometry, we used two composite PDMS materials whose densities were modulated by adding either microballoons or nickel powder. The use of two materials with different mass densities enabled precise control of the weight distribution to ensure a positive restoration force on the biorobot tilted at any angle. The developed biorobot exhibited unique propulsion modes depending on the resting angle of its "fin" or the cantilever, and achieved a maximum velocity of 142 μm s(-1). The technique described in this study to stabilize and propel the biorobot can pave the way for novel developments in biorobotics.

Biohybrid robot powered by an antagonistic pair of skeletal muscle tissues

“…Conventionally, many researchers have proposed biohybrid robots composed of a muscle tissue cultured on a flexible substrate and have succeeded in deformation of the substrate by contractions of the muscle tissues (2,3). These robots enabled biomimetic movementssuch as pumping (4), grasping (5)(6)(7), walking (7)(8)(9)(10), and swimming (11)(12)(13)(14)-by using design strategies based on the hearts, claws, inchworms, and aquatic organisms, respectively. Mainly cardiac and skeletal muscle tissues have been used as the muscle tissues for biohybrid robots because their contractions are generated by applying external stimulation, such as electrical (5-7, 9, 11) and optical (10,13) stimulations.…”

Untethered soft robotics

“…Other work has sought to control cell-attachment 47 and stability 48 in these machines to improve locomotion performance. Current progress in 3D bioprinting promises to facilitate further advances in bio-hybrid actuation 49 .…”

Dynamic Model for Characterizing Contractile Behaviors and Mechanical Properties of a Cardiomyocyte

“…Although the mechanical properties of the cells obtained using the proposed model-based method are not accurate for each structure of the living cell, they are valuable for analyzing the different mechanical properties of the subcellular structures between beating cells in different statuses for pathological analysis and drug screening. In addition, this work is useful to achieve optimal control of bio-syncretic robots, which may possess greater potential intrinsic safety and self-repair capability than traditional electromechanical robots (69), through the control of cellular performance such as beating frequency, amplitude, and contraction force, by adjusting the cells' structural characteristics using a targeted drug such as adrenaline, CD, Noc, colchicine, and paclitaxel (Taxol). The accuracy of these findings will be improved in further work, in which the fixed peak actuation force will be described by the action potential measured via patch clamp or artificial electric pulse stimulation; furthermore, system science theory will be adopted to study cells treated as mechanical systems stimulated by external import signals, such as vibration, electricity, and drug treatment.…”