Microfluidic generation of helical micromotors for muscle tissue engineering

Building units play an important and critical role in muscle tissue engineering, which has aroused increasing attention in recent decades. The current muscle units are suffering from over-simplified constructions and complicated fabrication approaches. Thus, we proposed a kind of helical micromotor with the technique of microfluidics to build tissue constructions for muscle tissue engineering. The desired micromotors were achieved by encapsulating muscle cells together with magnetic iron oxide nanoparticles (Fe 3 O 4 NPs) in helical microfibers with biocompatible materials. The helical structures and encapsulated Fe 3 O 4 NPs imparted micromotors with the capacity of advancing in rotation under magnetic fields; while biocompatible components made it possible for cell adhesion, proliferation, and migration. By adjusting the intensity of magnetic fields, the helical pitch of microfibers, or/and the concentration of Fe 3 O 4 NPs, the movement speed of the achieved micromotors could be changed correspondingly. Benefiting from the controllable movement and sufficient cell cultivation, the generated micromotors were capable of assembling together to form a cell mass construction in a relatively safe and convenient environment. Furtherly, fibroblasts could be cultured on the surface of the assembled cell units to achieve complex muscle tissue structures, which would be more similar to in vivo tissue units. These characteristics indicated that the desired helical micromotors had a great application prospect in tissue regeneration, artificial muscle, cell cultured meat and other fields.