Calcium silicate nanowires-containing multicellular bioinks for 3D bioprinting of neural-bone constructs

The significant guiding roles of nerves in bone formation and remodeling have been largely overlooked during the past decades when it comes to designing bone regeneration scaffolds. The requirement of intrabony nerve regeneration cannot be fulfilled by current therapeutic options, resulting in delayed innervation. Constructing a bone organoid which takes intrabony nerves into account can be a feasible approach. Herein, in combination with the nanocomposite bioinks and multicellular 3D bioprinting technology, a biomimetic neural-bone construct was successfully developed for innervated bone regeneration. Neural cells and bone-related cells were orderly printed to imitate the simplified spatial distribution of bone and nerves. Besides, inorganic calcium silicate (CS) nanowires were synthesized and incorporated into the bioinks to serve as “bioactive factors” to regulate multicellular behaviors. CS nanowires containing-bioinks could obviously promote the long-term survival and spreading as well as osteogenic and neurogenic differentiation of encapsulated cells. Furthermore, the in vivo results demonstrated that the CS nanowires containing-bioinks for 3D bioprinting of neural-bone constructs could simultaneously accelerate the new bone formation and ingrowth of nerve fibers. Taken together, this study offers a new concept by using inorganic nanomaterials as the bioactive components of bioinks for complex tissue regeneration, which represents a potential strategy for the fabrication of bone organoid with enhanced restoration of innervation and innervated bone tissues.