Enhanced Vascularity in Gelatin Scaffolds via Copper-Doped Magnesium-Calcium Silicates Incorporation: <i>In-Vitro</i> and <i>Ex-Ovo</i> Insights.

Addressing a critical challenge in current tissue-engineering practices, this study aims to enhance vascularization in 3D porous scaffolds by incorporating bioceramics laden with pro-angiogenic ions. Specifically, freeze-dried gelatin-based scaffolds were infused with sol-gel-derived powders of Cu-doped akermanite (Ca₂MgSi2O₇) and bredigite (Ca₇MgSi₄O₁₆) at various concentrations (10, 20, and 30 wt%). The scaffolds were initially characterized for their structural integrity, biodegradability, swelling behavior, impact on physiological pH, and cytocompatibility with human umbilical vein endothelial cells (HUVECs). The silicate incorporation effectiveness in promoting vascularity was then assessed through HUVEC attachment, capillary tube formation, and <i>ex-ovo</i> chick embryo chorioallantoic membrane assays. The findings revealed significant improvements in both <i>in-vitro</i> and <i>ex-ovo</i> vascularity of the gelatin scaffolds upon the addition of Cu-doped akermanite. The most effective concentrations were determined to be 10 and 20%, which led to notable HUVEC metabolic activity, a well-spread morphology with extensive peripheral filopodia and lamellipodia at 10% and a cobblestone phenotype indicative of <i>in-vivo</i> endothelium at 20% during cell attachment, the formation of complex networks of tubular structures, and robust vascularization in chick embryo development. Moving forward, the incorporation of Cu-doped akermanite into tissue-engineering scaffolds shows great potential for addressing the limitations of vascularization, especially for critical-sized bone defects, by facilitating the controlled release of pro-angiogenic and pro-osteogenic ions.