Coaxial 3D bioprinting of waterborne polyurethane scaffolds for repair of bone defects

Three-dimensional (3D) printing has transformed tissue engineering, enabling the creation of intricate structures with precise measurements and controlled porosity. Bioprinting, which deposits live cells into a 3D matrix to produce functional tissues, has gained significant attention. However, a major challenge in bioprinting is developing bioink that can sustain cell viability and facilitate tissue growth. In this article, we explored the use of bioprinting technology to engineer bone tissue using core-shell structures with living cells encapsulated in waterborne polyurethane ink. The images illustrate the hydrogels' capacity to form 3D scaffolds with high fidelity and integrity, without significant defects in the patterns. The results indicate that the bioprinted scaffold showed high cell viability and attachment. The cell viability was around 75% immediately after bioprinting for all scaffold formulations, and after one day of incubation, the viability increased to approximately 82%. In addition, according to alizarin red S staining and alkaline phosphatase activity results, the cells were able to differentiate into osteoblasts and produce an extracellular matrix, leading to the formation of bone tissue.