Collagen-based scaffolds loaded with iron oxide nanoparticles promote functional sensorimotor recovery in spinal cord injury

Spinal cord injury disrupts sensorimotor circuits, leading to chronic deficits that require coordinated repair of both spinal and supraspinal circuits. Here, we developed and evaluated a hybrid collagen hydrogel containing chitosan-functionalized iron oxide nanoparticles as a therapeutic scaffold to promote multi-level recovery in a C6 hemisection model in rats. In vitro, both the nanoparticles and the resulting hybrid scaffold show preserved neuronal viability, excitability, and network connectivity. In vivo, scaffold-implanted rats demonstrate significant improvements in gross motor function and postural control, as well as recovery of fine motor skills, forelimb dexterity and grip strength. Sensory evaluations show preserved hindlimb tactile responses accompanied by plasticity within the somatosensory cortex, indicating functional recovery of the different tracts related to sensory and motor functions. At the lesion site, the scaffold enhances neurite outgrowth and modulates the inflammatory milieu, providing a permissive environment for neural repair. These findings indicate that these hybrid collagen scaffolds support relevant integrated structural and functional recovery features after SCI and represent a promising platform for further optimization toward the effective release of therapeutics at the injured spinal cord.