Multifunctional Hydroxyapatite Nanobelt Haystacks Integrated Neural Stem Cell Spheroid for Rapid Spinal Cord Injury Repair

Abstract Due to the unwarranted lifespan and differentiation, applying neural stem cells (NSCs) in spinal cord injury (SCI) remains challenging. In this study, 3D bioactive hydroxyapatite (HAp) nanobelt haystack‐mouse NSC (mNSC) hybrid spheroids are customized in which the specific nanobelt haystack framework provided the structural function of hypoxia alleviation in the spherical core and biological process of neural differentiation promotion. Commodified with superparamagnetic ferroferric oxide (Fe 3 O 4 ) nanoparticles and a polydopamine (PDA) coating, the HAp nanobelts are endowed with magnetic field‐driven properties and enhanced cell‐nanobelt adhesion. The engineered bioresponsive 3D nanobelt haystack‐mNSC hybrid spheroids effectively repair SCI in vivo, showing new potential for stem cell therapy by incorporating nanomaterials in 3D culture based on cell‐material interactions.