3D-Printing and Biofunctionalization of PCL-Based Nanocomposite Scaffolds for Osteogenic Differentiation

Abstract Three-dimensional printed porous scaffolds offer biophysical and biochemical support for surrounding cells, mimicking the extracellular matrix (ECM) in bone tissue engineering. Bone tissue engineering scaffold is intended to provide hydrophilicity, cytocompatibility and delivery of diverse bioactive molecules such as growth factors and enzymes to exhibit cell attachment, proliferation, osteogenic differentiation and calcification. Alkaline phosphatase enzyme is an essential biomolecule due to its significant role in bone mineralization and cell differentiation. This study immobilizes alkaline phosphatase enzyme (ALP) and dopamine on a 3D-printed polycaprolactone/TiO2 nanocomposite via solvent soaking. Characterization includes contact angle, compressive strength test, EDX, ATR, and XRD analysis. In vitro cell studies on PCL, PCL/nTiO2, PCL/nTiO2/Dopamine, and PCL/nTiO2/dopamine/ALP 3D-printed scaffolds evaluate osteogenic differentiation and cell viability using ALP activity on rat adipose-derived mesenchymal stem cells (MSCs) and MTT assay on the L929 cell line. FTIR confirms nanoparticle presence in the scaffold, while XRD and compressive tests show that the crystallinity degree and mechanical properties of the PCL scaffold are higher than nanocomposite scaffolds. Dopamine increases the hydrophilicity of PCL, enhancing biological behavior and expressing significant osteogenic effects. The PCL/nTiO2/Dopamine/ALP group shows the most ALP activity after 3 days. ALP assay exhibits acceptable differentiation in the absence of ALP for nanocomposite scaffolds after 7 days of incubation. TiO2 considerably increases osteogenic differentiation after 10 days, up to about 100%, compared to the sample containing osteogenic medium. This study highlights the potential for designing novel biofunctionalized 3D nanocomposite scaffolds with osteogenic properties for bone tissue engineering applications.