Design and fabrication of a hybrid piezoelectric bone scaffold using melt electrowriting (MEW) of PCL and FDM 3D-Printing of PVDF

The ability to fabricate scaffolds that closely resemble the structural characteristics of natural bone remains one of the major challenges in bone tissue engineering. Moreover, developing materials for scaffold fabrication that can accelerate the regeneration process is another important issue. A hybrid scaffold was developed in this study using a combination of material extrusion (MEX) technologies, namely melt electrowriting (MEW) and fused deposition modeling (FDM), to mimic the hierarchical architecture of natural bone, consisting of cancellous and cortical regions. The cancellous region was fabricated via MEW using polycaprolactone (PCL), while the cortical region was produced through FDM employing polyvinylidene fluoride (PVDF). The two sections were subsequently integrated to form the complete scaffold. The incorporation of PVDF enabled cellular stimulation under mechanical loading, thereby enhancing cell growth within the scaffold. These hybrid scaffolds were also compared with scaffolds fabricated using the FDM. The results of compressive mechanical testing showed that the scaffolds with a PVDF shell exhibited the highest compressive strength, with a value of 70.9 MPa. Furthermore, tensile testing indicated that the PCL (MEW) exhibited the highest strain tolerance, with an ultimate tensile strength of 6.95 MPa. In addition, MTT assay revealed high cell viability, with values of 92% for the hybrid scaffold and 87% for PCL (FDM). Consequently, an improved scaffold was proposed for application in bone tissue regeneration.