Tissue-Specific Hydrogels for Three-Dimensional Printing and Potential Application in Peripheral Nerve Regeneration

Impact statementTissue-derived decellularized matrices have drawn broad interests for their versatile applications in tissue engineering and regenerative medicine, especially the decellularized peripheral nerve matrix, which can effectively facilitate axonal extension, remyelination, and neural functional restoration after peripheral nerve injury. However, neither decellularized porcine nerve matrix (pDNM) nor pDNM hydrogel (pDNM-G) can be directly used in three-dimensional printing for personalized nerve constructs or cell transplantation. This work developed a hybrid hydrogel consisting of decellularized extracellular matrix hydrogel (dECM-G) and photocrosslinkable gelatin methacrylate (GelMA), which resulted in significantly improved printability and structural fidelity. The GelMA/pDNM-G hydrogel retained high bioactivity and tissue-specificity due to its dECM-G content. Such hybrid hydrogel systems built up a springboard in advanced biomaterials for neural tissue engineering, as well as a promising strategy for dECM containing bioprinting. Decellularized extracellular matrix hydrogel (dECM-G) has demonstrated its significant tissue-specificity, high biocompatibility, and versatile utilities in tissue engineering. However, the low mechanical stability and fast degradation are major drawbacks for its application in three-dimensional (3D) printing. Herein, we report a hybrid hydrogel system consisting of dECM-Gs and photocrosslinkable gelatin methacrylate (GelMA), which resulted in significantly improved printability and structural fidelity. These premixed hydrogels retained high bioactivity and tissue-specificity due to their containing dECM-Gs. More specifically, it was realized that the hydrogel containing dECM-G derived from porcine peripheral nerves (GelMA/pDNM-G) effectively facilitated neurite growth and Schwann cell migration from two-dimensional cultured dorsal root ganglion explants. The nerve cells were also encapsulated in the GelMA/pDNM-G hydrogel for 3D culture or underwent cell-laden bioprinting with high cell viability. The preparation of such GelMA/dECM-G hydrogels enabled the recapitulation of functional tissues through extrusion-based bioprinting, which holds great potential for applications in regenerative medicine.