University of Edinburgh - Dissertation
Multi-material 3D printing to mimic the osteo-tendinous enthesis
Summary
My final year project involved researching the possibilities of multi-material 3D printing. I used TPU and a variety of rigid thermoplastics to produce test coupons for tensile testing at the University of Dundee. Additionally, I explored the cytotoxicity and cell adhesiveness of these matierals using rat osteoblasts.
Abstract
Injuries to the attachment site of tendons or ligaments to bones (entheses) are common, such as tennis elbow. The enthesis has a highly complex and organised structure to dissipate the force generated by muscles to the underlying rigid bone without damaging the compliant tendon. However, current repair of these injuries does not recapitulate this architecture and is consequently prone to reinjury. Here, a model of the enthesis is produced using multi-material 3D printing, and its tensile properties evaluated. Three joint types and five materials were evaluated. It was shown that this technique was able to mimic the ultimate tensile strength of the human extensor digitorum brevis tendon. Additionally, cytotoxicity and cell adhesion assays demonstrated the viability of these materials to support osteoblasts in vitro. Finally, an anatomically correct scaffold of the distal phalanx and flexor digitorum profundus tendon was produced. Overall, this project has demonstrated a proof-of-concept of a viable technique to develop customisable, anatomically relevant, non-cytotoxic, cell-adhesive scaffolds for entheseal tissue engineering with adequate tensile properties and an interface between rigid and compliant materials.
