Synergistic, shape-controlled endothelialized spheroid-hydrogel for wound healing.

Abstract

For healing full-thickness skin defects caused by severe injury, skin substitute grafts with structural and compositional biomimicry are critical. Vascularized spheroids, as highly active biological building blocks, can be applied in biomanufacturing to fabricate functional repair constructs. However, current methods of biofabricating endothelialized spheroids still face multiple technical limitations, including low throughput, poor uniformity, and insufficient controllability and observability. Furthermore, there is inadequate control over the spatial arrangement of the spheroids during vascularized construct biomanufacturing. We proposed a synergistic, shape-controlled spheroid-hydrogel biomanufacturing method to address these issues, and developed a highly integrated, one-stop bioprinting platform for spheroids (OBPS) with real-time monitoring. We focused on key biomanufacturing stages, spheroid fabrication, bioprinting, and in vivo validation, to establish an integrated technical framework providing for "fabrication-culture-assembly-application." Using the OBPS, we fabricated endothelialized spheroids by co-culturing human fibroblasts and human umbilical vein endothelial cells, printed fibrinogen-supplemented gelatin methacryloyl hydrogel, and bioprinted spheroids and hydrogels in situ onto full-thickness skin defects in nude mice. Animal experiments show that shape-controlled endothelialized spheroids significantly accelerated wound closure, suppressed inflammation, promoted neovascularization and collagen remodeling, and exhibited excellent tissue integration and repair potential. The OBPS system provides a novel and effective treatment for wound healing.