Melt electrowriting of hydrophilic/hydrophobic multiblock copolymers for bone tissue regeneration

Bone-healing complications can occur due to large bone defects or an insufficient bone regeneration capacity. Melt electrowriting (MEW) is a potential candidate for manufacturing synthetic scaffolds that may resolve bone-healing complications. MEW can exploit various biocompatible polymers with a wide range of tissue engineering applications. Poly (ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT), a multiblock copolymer family, has emerged as a promising biomaterial to guide cell behavior, particularly in promoting bone differentiation. The polymer is known for its tunability by varying the PEOT/PBT weight ratios to influence the chemical, physical and mechanical properties. Four carefully selected PEOT/PBT compositions investigated in this study with the poly (ethylene oxide terephthalate) content ranging from 36 and 65 wt%. Detailed rheological characterization was performed to determine the optimum printing temperature, followed by optimizing the MEW parameters to fabricate a well-defined and layer-by-layer scaffold for each copolymer composition. The effect of distinct physicochemical properties on cell behavior was also investigated using MG63 cells on both 2D films and MEW scaffolds. MEW scaffolds made from each polymer compositions show good cell attachment and proliferation along with flattened cell morphology in contrast with highly varied performance on 2D films. In addition, the in vitro bioactivity test using simulation body fluid reveals the formation of bone-like apatite layer formation on the MEW scaffolds made from high molecular weight and poly (ethylene oxide terephthalate) composition.