Tissue-Engineering Approach to Making Soft Actuators

Abstract

Recent achievements in tissue-engineering research make it viable to construct biological tissue and organs in vitro from living cells and a scaffold substrate. This technology can be applied not only to patients for regenerating malfunctioning tissue and organs in vivo but also to other purposes such as threedimensional tissue modeling for drug screening in vitro. The aim of this chapter is to describe bioactuators, which are actuators made of cultured skeletal muscle cells in vitro, on the basis of our investigations. Living muscles are driven by actin-myosin molecular motors through transformation of the biochemical energy of adenosine triphosphate (ATP) into mechanical energy. They have excellent characteristics of light weight, high flexibility, and remarkable efficiency for energy conversion in comparison with mechanical actuators that require electricity as a power source. Therefore, bioactuators have the potential to be flexible and highly efficient actuators on a micro- to macroscale. Tissue-engineered skeletal muscle with a native-like contractile property has been successfully constructed and adapted as a bioactuator to drive a microlever object. There are still several issues to be resolved for creation of a large and powerful bioactuator that works long term with proven reliability, and these are expected to be addressed in the near future through intensive and vigorous tissue-engineering studies.