Supplementary material from "Dual-photoresponsive Elastomer Nanofibres Enhanced Myofibre Hybrid for Skeletal Muscle Actuation"

Light-responsive polymers hold great promise for remote or battery-free actuation in soft robotics. Yet, current systems often suffer from the limited responsiveness, processability, and biocompatibility—challenges that are particularly critical for muscle restoration applications. Here, we introduce MyoHybrid, a “dual-photoresponsive” skeletal muscle actuator combining optogenetic myofibres with a scalable, unidirectionally aligned polyurethane–azobenzene (PAzo) nanofiber scaffold. The term “dual-photoresponsive” refers to the synergy between intrinsic PAzo photoactuation—driven by coupled photochemical and photothermal effects—and optogenetically induced myofiber contractions. This anisotropic integration enables cooperative light-driven actuation of both nanofibers and myotubes. Compared to PAzo flat solid substrate, aligned PAzo nanofibers improved unidirectional myotube fusion by 25.3% and enhanced maturation by 37.7%. Furthermore, optogenetic stimulation of the resulting myofibers led to a 60% increase in contraction velocity and force relative to glass controls. MyoHybrid established a seamless interface between synthetic nanofibers and biological myofibers, offering a programmable platform for muscle-on-chip models, biohybrid actuators, and light-driven soft tissue systems. This work bridges mechanical bionics and cellular actuation, advancing next-generation soft robotics and regenerative technologies.