Bioinspired porous core-shell microspheres with spatiotemporal delivery coordinate immunomodulatory-osteogenic coupling via NF-κB/P-STAT6 and Rho/MAPK signaling for enhanced calvarial regeneration

Critical-sized calvarial defects remain a formidable clinical challenge due to dyssynchronous immunomodulation-osteogenesis coupling and unregulated growth factor release. Here, a bioinspired porous core-shell microsphere system (GCI@HPPS) is developed, integrating hydroxyapatite (HA)-loaded shell, surface-immobilized SDF-1α, and IGF-1-encapsulated cores to immunomodulate osteoimmune microenvironment and osteogenesis promotion. The hierarchical architecture achieved spatiotemporally programmed release: HA degradation-dependent mineralization, SDF-1α-mediated BMSC chemotaxis, and sustained IGF-1 delivery, mimicking natural bone repair cascades. Dual covalent/guest-host crosslinking (GelMA/Ac-β-CD) enhanced compressive strength, while polydopamine functionalization of microspheres conferred electroactivity, hydrophilicity, ROS/RNS scavenging (97.29 % ABTS•+ elimination), antibacterial efficacy (>99.8 %) and hemostasis. In vitro , GCI@HPPS mitigates oxidative stress, induces M2 macrophage polarization, and suppresses inflammatory cascades while concomitantly enhancing endogenous BMSC recruitment, proliferation, and osteogenic differentiation. Proteomics revealed a tetradic anti-inflammatory mechanisms of GCI@HPPS: NF-κB/P-JNK suppression, pro-inflammatory cytokines downregulation, mitochondrial oxidative modulation, and STAT6-driven M2 polarization. In vivo , GCI@HPPS achieved calvarial defect closure at 8 weeks through porous matrix-guided cellular infiltration, and SDF-1α/IGF-1-mediated chemotaxis, Rho/MAPK signaling pathway activation balancing osteoclast-osteoblast dynamics, stage-specific osteogenic induction and AGE-RAGE/VEGF-coupled angiogenesis-osteogenesis. This work pioneers a spatiotemporal delivery paradigm that coordinates inflammation modulation, stem cell recruitment, osteogenic differentiation, and mineralization phases, offering a promising approach for complex cranial reconstruction. Bioinspired porous core-shell microsphere (GCI@HPPS) is designed for sequential therapeutic factors delivery to synchronize immunomodulation and osteogenic regeneration. The anti-inflammatory mechanisms of GCI@HPPS are NF-κB/P-JNK suppression, pro-inflammatory cytokine downregulation, mitochondrial oxidative modulation, and STAT6-driven M2 polarization. GC@HPPS achieves cranial reconstruction by SDF-1α/IGF-1-mediated chemotaxis, Rho/MAPK signaling pathway activation balancing osteoclast-osteoblast dynamics, stage-specific osteogenic induction (OSX/Runx2-BMP-2/Col-I/ALP/OPN-OCN/calcium deposition) and AGE-RAGE/VEGF-coupled angiogenesis-osteogenesis. • Core-shell porous microsphere (GCI@HPPS) enables spatiotemporal delivery of immunomodulatory-osteogenic factors. • GCI@HPPS mitigates oxidative stress, induces M2 macrophage polarization, and suppresses inflammatory cascades. • GCI@HPPS enhances endogenous BMSC recruitment, proliferation, and osteogenic differentiation. • GCI@HPPS immunomodulates osteoimmune microenvironment and osteogenesis promotion.