3D bioprinting: A new insight into the therapeutic strategy of neural tissue regeneration.

Acute traumatic injuries and chronic degenerative diseases represent the world's largest unmet medical need. There are over 50 million people worldwide suffering from neurodegenerative diseases. However, there are only a few treatment options available for acute traumatic injuries and neurodegenerative diseases. Recently, 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. In this commentary, the newly developed 3D bioprinting technique involving neural stem cells (NSCs) embedded in the thermoresponsive biodegradable polyurethane (PU) bioink is reviewed. The thermoresponsive and biodegradable PU dispersion can form gel near 37 °C without any crosslinker. NSCs embedded within the water-based PU hydrogel with appropriate stiffness showed comparable viability and differentiation after printing. Moreover, in the zebrafish embryo neural deficit model, injection of the NSC-laden PU hydrogels promoted the repair of damaged CNS. In addition, the function of adult zebrafish with traumatic brain injury was rescued after implantation of the 3D-printed NSC-laden constructs. Therefore, the newly developed 3D bioprinting technique may offer new possibilities for future therapeutic strategy of neural tissue regeneration.