3D-Bioprinted Scaffolds with Precise Factor Delivery for Spinal Cord Injury Repair.

Spinal cord injury (SCI) remains a major global health challenge, often resulting in the permanent loss of motor and sensory functions. To address this issue, we developed a 3D-bioprinted precision location scaffold to promote SCI repair. The scaffold was designed to incorporate region-specific growth factors tailored to the distinct functions of gray and white matter in the spinal cord. This spatial arrangement aimed to optimize the proliferation and neural differentiation of induced ectodermal mesenchymal stem cells (EMSCs). In vitro results showed that induced EMSCs proliferated significantly within the simulated gray matter hydrogel and expanded markedly in the simulated white matter hydrogel, highlighting the scaffold's ability to mimic the natural spinal cord environment. In vivo results presented that the precision location scaffold notably enhanced the recovery of limb motor function in SCI rats. Mechanistic studies revealed that the scaffold significantly upregulated key neuronal markers such as GAP43, nestin, and Tuj1, while simultaneously reducing GFAP expression, indicating a reduction in the level of glial scar formation and supporting nerve regeneration. These findings suggested that the precise spatial delivery of growth factors within the scaffold can effectively create a regenerative microenvironment at the SCI site. Furthermore, induced EMSCs, acting as seed cells, play a crucial role in promoting spinal cord repair. This study demonstrates the feasibility and potential of 3D bioprinting technology for regenerative medicine, offering promising applications in neural tissue engineering for SCI treatment.