Engineering a multilayered thin-film agarose-based hydrogel to support adipose-derived stromal vascular fraction...

Acute spinal cord injury (SCI) remains a devastating neurological condition with limited therapeutic options. While cell therapy using adipose-derived stromal vascular fraction (SVF) represents a promising approach, effective delivery strategies are critical for clinical success. To address this challenge, this study introduces an innovative therapeutic platform based on a multi-layered thin-film hydrogel, specifically engineered to optimize SVF cell delivery and functionality. By overcoming the critical limitations of traditional bulk hydrogels-such as restricted nutrient diffusion and heterogeneous cell distribution-this layered architecture ensures a uniform cellular microenvironment throughout the three-dimensional space. To further enhance biological performance, an extracellular matrix (ECM) pre-deposition strategy was implemented. By pre-coating the hydrogel layers with SVF-derived ECM, a highly supportive niche was established that significantly promotes cell adhesion and prolonged viability compared to naïve scaffolds. In vivo assessments using intravital microscopy in an SCI model demonstrated the superior efficacy of this system. Specifically, the layered hydrogel successfully preserved SVF viability for extended periods, marking a significant improvement over direct intraparenchymal injections, which resulted in rapid cell degeneration. Furthermore, the hydrogel construct exhibited potent paracrine activity, effectively modulating the hostile injury microenvironment by significantly downregulating pro-inflammatory markers while upregulating anti-inflammatory and pro-angiogenic factors. Ultimately, the inherent modularity and scalability of this thin-film design allow for precise customization to various lesion geometries, representing a significant advancement in regenerative medicine with high translational potential for treating complex spinal trauma.