Melt Electrowriting of Elastic Scaffolds Using PEOT-PBT Multi-block Copolymer.

Melt electrowriting (MEW) is a powerful additive manufacturing technique to produce tissue engineering scaffolds. Despite its strength, it is limited by a small number of processable polymers. Therefore, to broaden the library of materials for MEW, we investigated the printability of poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT-PBT), a thermoplastic elastomer. The effect of different printing parameters and material thermal degradation are studied. It is observed that the material is stable for >60 min at a printing temperature of 195 °C in a nitrogen environment. Next, two types of designs are printed and characterized: mesh-like and semi-random scaffolds. For both types of designs, PEOT-PBT scaffolds reveal a higher yield strain, and lower Young's modulus as compared to control polycaprolactone scaffolds. Biological studies performed using mouse embryonic fibroblasts (NIH-3T3) show good cell viability and metabolic activity on all print scaffolds. SEM imaging reveals actively migrating cells on PEOT-PBT mesh scaffolds after 24 h of culture and 98.87% of pore bridging by cells after 28 days of culture. Immunofluorescence staining shows decreased expression of alpha-smooth muscle actin from day 14 to day 28 in PEOT-PBT mesh scaffolds. Overall, it is shown that melt electrowritten PEOT-PBT scaffolds have great potential for soft tissue regeneration.