Magnetic 3D bioprinting of skeletal muscle spheroid for a spheroid-based screening assay

Over the past decade, there has been a rapid development in the use of magnetic three dimensional (3D) based cell culture systems. Concerning the skeletal muscle, 3D culture systems can provide biological insights for translational clinical research in the fields of muscle physiology and metabolism. These systems can enhance the cell culture environment by improving spatially-oriented cellular assemblies and morphological features closely mimicking the in vivo tissues/organs, since they promote strong interactions between cells and the extracellular matrix (ECM). However, the time-consuming and complex nature of 3D traditional culture techniques pose a challenge to the widespread adoption of 3D systems. Herein, a bench protocol is presented for creating an innovative, promptly assembled and user-friendly culture platform for the magnetic 3D bioprinting of skeletal muscle spheroids. Our protocol findings revealed consistent morphological outcomes and the functional development of skeletal muscle tissue, as evidenced by the expression of muscle-specific contractile proteins and myotubes and the responsiveness to stimulation with cholinergic neurotransmitters. This proof-of-concept protocol confirmed the future potential for further validation and application of spheroid-based assays in human skeletal muscle research.