Sodium Alginate Hydrogel with Zinc Ion Nanoparticles for Synergistic Neuroprotection and Functional Recovery in Spinal Cord Injury.

Source: PubMed, NCBI / U.S. National Library of Medicine

The current lack of effective treatments for traumatic spinal cord injury (SCI) presents a significant challenge in managing the complex microenvironmental alterations that follow the initial trauma. This study developed an injectable alginate hydrogel dynamically cross-linked by tannic acid-zinc nanoparticles (TA@Zn NPs), which exerts neuroprotective effects through the sustained release of zinc ions (Zn) and antioxidant TA@Zn NPs. TA@Zn NPs were cross-linked with phenylboronic acid-modified sodium alginate (SA) to form an injectable gel system. In response to the acidic and ROS-rich microenvironment characteristic of SCI, the hydrogel undergoes degradation, thereby triggering the disintegration of TA@Zn NPs and the concomitant release of Zn, enabling sustained therapeutic delivery. In a rat model of contusion injury, the degradation of TA@Zn NPs and the sustained release of Znsignificantly reduced oxidative damage and promoted axonal regeneration, which in turn inhibited scar formation and enhanced the tissue's antioxidant capacity. Consequently, the group treated with the Zn-releasing hydrogel exhibited significant recovery of motor function. Collectively, these results validate the dual-function integration of Znas a dynamic cross-linker and neuroprotective agent within injectable hydrogels as a robust strategy for SCI repair, presenting a clinically translatable paradigm for neural regeneration.