Regional and sustained dual-release of growth factors from biomimetic tri-layered scaffolds for the repair of large-scale osteochondral defects

•Tri-layered scaffolds with mimicking osteochondral structure.•Tri-layered scaffolds were functionalized to provide local and sustained release of double growth factors.•The ability of hUCMSCs to differentiate into chondrocytes or osteoblasts were enhanced.•Tri-layered scaffolds significantly accelerated the repair of large-size osteochondral defects.