Ultralight Conductive and Elastic Aerogel for Skeletal Muscle Atrophy Regeneration

Cell-free materials that can transmit both mechanical and electrical stimulations provide a promising strategy for myoinjury repair. Skeletal muscle is sensitive to electrical stimulation (ES), and accordingly, materials are required to transmit the electrical signal while maintaining their elasticity to build the cellular communication network in denervated muscle for retarding muscle atrophy. Here, tannic acid functionalized with methacrylate group (TA-MA), dopamine, and hydrothermal reduction are employed in multistep base reduction to fabricate a polydopamine (PDA)/reduced graphite oxide (rGO) aerogel. This mussel-inspired PDA/rGO aerogel possesses good conductivity, electromechanical stability, and appropriate Young's modulus, which are favorable for the growth and differentiation of C2C12 myoblasts. After the cell-free PDA/rGO aerogel-transplanted denervated muscle is loaded with cyclic ES for 3 weeks, the mean muscle fiber size increases by 90% and the maximum contraction force of denervated muscle elevates by 50%, accompanied with a slight inflammation infiltration in muscle. In conclusion, PDA/rGO aerogel is a safe and effective implant for retarding the disuse muscle atrophy.