Development of an osteo-angiogenic scaffold derived from decellularization of spheroid-embedded 3D constructs for vascularized bone regeneration

Abstract

The regeneration of vascularized bone tissue requires biomaterials that deliver coordinated osteogenic and angiogenic signals within mechanically robust three-dimensional architectures. Here, we present a decellularized osteo-angiogenic scaffold generated by integrating mineral-coated nanofiber-incorporated human adipose-derived stem cell spheroids into a 3D-printed polymer scaffold. The mineral-coated spheroids enhanced extracellular matrix (ECM) deposition and osteogenic priming during preculture, and subsequent decellularization efficiently removed cellular components while preserving osteoinductive matrix proteins and pro-angiogenic growth factors. The resulting cell-free scaffold established a homogeneous, multifunctional signaling microenvironment that supported host cell infiltration and potently induced coupled osteogenic and angiogenic responses in vitro without exogenous growth factor supplementation. In a murine critical-sized calvarial defect model, the mineralized scaffold achieved significantly enhanced neovascularization (16±1 α-SMA+ arterioles/mm²) and mature lamellar bone formation (66.2±5.9% BV/TV) compared with the non-mineralized controls. This work introduces a stem cell-derived, ECM-enriched 3D scaffold platform that couples osteogenesis and angiogenesis through endogenous bioactive cues, providing a clinical translation strategy for vascularized bone regeneration.