High-Resolution DLP Printing of Elastic GelMA Hydrogel Scaffolds with Vascular-Mimetic Architecture for Microvascular Regeneration

Background: The fabrication of vascular-mimetic hydrogel scaffolds with precise luminal geometry, suitable elasticity, and good cytocompatibility remains a major challenge in tissue engineering. Digital light processing (DLP) printing offers high resolution and rapid fabrication, but over-curing and limited structural fidelity in hollow constructs still restrict its application in vascular-like scaffold fabrication. Methods: In this study, GelMA-based tubular scaffolds with Y-shaped and curved vascular geometries were fabricated by DLP printing. To improve printing precision, 0.02% (w/v) tartrazine was introduced as a light-absorbing agent to regulate light penetration and curing depth during the photopolymerization process. The printed scaffolds were characterized by optical imaging and scanning electron microscopy, while their mechanical properties were evaluated through tensile and compression tests. Cytocompatibility was assessed using CCK-8 assay, Live/Dead staining, and quantitative cell survival analysis. Results: The incorporation of tartrazine effectively reduced excessive light penetration during printing, enabling the formation of continuous tubular structures with improved lumen definition and structural integrity. The DLP-printed GelMA scaffolds showed high geometric fidelity, with smooth and stable inner channels of approximately 1 mm in diameter. Mechanical testing demonstrated a nonlinear J-shaped tensile response and strain-stiffening behavior under compression, indicating favorable elasticity and resistance to deformation. In vitro biological evaluation further showed high cell viability, with CCK-8 results remaining above the control level and Live/Dead staining confirming a predominance of viable cells on the scaffold surface. Conclusion: The incorporation of a small amount of photoabsorber enabled high-resolution DLP printing of vascular-like GelMA scaffolds with excellent mechanical flexibility and biocompatibility. These constructs hold strong potential as perfusable, elastic hydrogel platforms for microvascular regeneration, endothelialization studies, and organ-on-chip applications.