(150ae) Hierarchically Porous Slit3-Releasing PLGA/Hydroxyapatite Composite Scaffold for Bone Tissue Engineering

Three-dimensional printing technology offers adaptable design possibilities, precise geometrical control, and feasible surface modification; however, limited number of biomaterials and biostructures can be obtained via the direct 3D printing which would restrict the opportunities needed to mimic the bone extracellular matrix. In this work, the indirect 3D printing technique was utilized to produce a hierarchically porous SLIT3-releasing PLGA/hydroxyapatite nanocomposite coated with polydopamine (PLGA-HA,NPs-PDA) scaffold. The developed scaffold was characterized using a range of chemical, architectural, mechanical, and biological investigation techniques. The optimal scaffold provided a unique microstructure with an average pore size of 178.06 µm and 63% porosity, stable chemical composition, mechanical compression strength up to 4.95 MPa at 90% strain, controlled release of Slit3 protein, biodegradability, and biocompatibility for mesenchymal stem cell culturing. Interestingly, emplying Slit3 protein as biological modifier and activator of stem cell proliferation and differentiation instead of cytokines or other traditional proteins within bone tissue scaffold is still unclear and needs more investigation. Herein, the SLIT3 protein bioactivity toward mesenchymal stem cells (MSCs) growth in the optimized polymeric scaffold matrix had been addressed for the first time. As a result, MSCs were successfully cultured and nicely thrived within the scaffold microstructure. However, this outcome highlights the improved biocompatibility, matched mechanical and architecture properties, and protein’s efficacy of the proposed SLIT3-releasing scaffold. The obtained results pave the way for more comprehensive in-vitro and in-vivo assessment.