3D-printing of dipyridamole/thermoplastic polyurethane materials for bone regeneration

Tissue engineering combines biology and engineering to develop constructs for repairing or replacing damaged tissues. Over the last few years, this field has seen significant advancements, particularly in bone tissue engineering. 3D printing has revolutionised this field, allowing the fabrication of patient- or defect-specific scaffolds to enhance bone regeneration, thus providing a personalised approach that offers unique control over the shape, size, and structure of 3D-printed constructs. Accordingly, thermoplastic polyurethane (TPU)-based 3D-printed scaffolds loaded with dipyridamole (DIP) were manufactured to evaluate their in vitro osteogenic capacity. The fabricated DIP-loaded TPU-based scaffolds were fully characterised, and their physical and mechanical properties analysed. Moreover, the DIP release profile, the biocompatibility of scaffolds with murine calvaria-derived pre-osteoblastic cells, and the intracellular alkaline phosphatase (ALP) assay to verify osteogenic ability were evaluated. The results suggested that these materials offered an attractive option for preparing bone scaffolds due to their mechanical properties. Indeed, the addition of DIP in concentrations up to 10% did not influence the compression modulus. Moreover, DIP-loaded scaffolds containing the highest DIP cargo (10% w/w) were able to provide sustained drug release for up to 30 days. Furthermore, cell viability, proliferation, and osteogenesis of MC3T3-E1 cells were significantly increased with the highest DIP cargo (10% w/w) compared to the control samples. These promising results suggest that DIP-loaded TPU-based scaffolds may enhance bone regeneration. Combined with the flexibility of 3D printing, this approach has the potential to enable the creation of customized scaffolds tailored to patients' needs at the point of care in the future.