Biological Soft Robotics

Abstract

In nature, nanometer-scale molecular motors are used to generate force within cells for diverse processes from transcription and transport to muscle contraction. This adaptability and scalability across wide temporal, spatial, and force regimes have spurred the development of biological soft robotic systems that seek to mimic and extend these capabilities. This review describes how molecular motors are hierarchically organized into larger-scale structures in order to provide a basic understanding of how these systems work in nature and the complexity and functionality we hope to replicate in biological soft robotics. These span the subcellular scale to macroscale, and this article focuses on the integration of biological components with synthetic materials, coupled with bioinspired robotic design. Key examples include nanoscale molecular motor-powered actuators, microscale bacteria-controlled devices, and macroscale muscle-powered robots that grasp, walk, and swim. Finally, the current challenges and future opportunities in the field are addressed.

Advances in engineering hydrogels

“…Applications such as load-bearing bio-materials (39, 43), soft robotics (44), and wearable devices (4–6) have spurred interest in developing tough and highly stretchable hydrogels as a class of soft and hydrated substrates.…”

In vitro drug testing based on contractile activity of C2C12 cells in an epigenetic drug model

“…Tissue-engineered skeletal muscle constructs have attracted attention for regenerative therapy1, basic biological studies2, bio-actuators3, as a meat alternative4, and for drug discovery5. In vitro culture systems have been applied for drug discovery for patients with injured, diseased and age-related muscle dysfunction67.…”

Biomimetic approaches toward smart bio-hybrid systems

“…Biological systems have evolved to display sophisticated mechanisms of sensing, actuation, and adaptation when external stimuli are applied. Therefore, the integration of highly dynamic and adaptable cells or tissues with soft artificial systems represents a promising strategy to building intelligent soft robotics with the ability to process signals and adapt to external stimuli in real time [17, 18]. For example, using cardiomyocytes and muscles, which contract autonomously or upon electrical stimulation, bio-hybrid robotics have been designed to perform precisely controlled actuation and even net locomotion [54–57].…”

“…These 3D bio-hybrids not only represent an innovative strategy to developing new generations of bio-integrated devices for diagnostics and therapeutics [11–14], but also open up new opportunities for fundamental research, such as a smart organ-on-a-chip system for real time cell physiology studies [15, 16]. Moreover, the bio-hybrid platform also represents a new avenue for building “living” electronic or mechanic devices, such as engineered tissue-based soft robotics [17, 18]. …”