Wnt3a-induced ST2 decellularized matrix ornamented PCL scaffold for bone tissue engineering

The limited bioactivity of scaffold materials is an important factor that restricts the development of bone tissue engineering. Wnt3a activates the classic Wnt/β-catenin signaling pathway which effects bone growth and development by the accumulation of β-catenin in the nucleus. In this study, we fabricated 3D printed PCL scaffold with Wnt3a-induced murine bone marrow-derived stromal cell line ST2 decellularized matrix (Wnt3a-ST2-dCM-PCL) and ST2 decellularized matrix (ST2-dCM-PCL) by freeze-thaw cycle and DNase decellularization treatment which efficiently decellularized >90% DNA while preserved most protein. Compared to ST2-dCM-PCL, Wnt3a-ST2-dCM-PCL significantly enhanced newly-seeded ST2 proliferation, osteogenic differentiation and upregulated osteogenic marker genes alkaline phosphatase (Alp), Runx2, type I collagen (Col 1) and osteocalcin (Ocn) mRNA expression. After 14 days of osteogenic induction, Wnt3a-ST2-dCM-PCL promoted ST2 mineralization. These results demonstrated that Wnt3a-induced ST2 decellularized matrix improve scaffold materials’ osteoinductivity and osteoconductivity.