Design and Validation of an Open-Source 3D Printable Bioreactor System for Ex Vivo Bone Culture

Abstract

In Canada, osteoporosis is a prevailing skeletal disease that is underdiagnosed and undertreated, with an annual economic cost of $4.6 billion. Trabecular bone is widely understood to undergo modelling and remodelling in response to biochemical and mechanical loads during physical activity. Further insights into the adaptation process of bone could help clinicians improve prevention and treatment methods, including physical activity recommendations, and lead to increased bone health. Previous studies have successfully implemented a polycarbonate (PC) bioreactor system to study trabecular bone adaptation in response to biochemical and mechanical stimulation in long-term ex vivo bone organ culture. However, the PC bioreactors are expensive and difficult to fabricate and have been limited to testing bone cores with maximum dimensions of 5 mm x 10 mm (height x diameter), which is below recommended standards for bone compression testing. Recent advancements in additive manufacturing can reduce fabrication cost and difficulty and allow for high dimensional precision in 3D printed designs with biocompatible material options. Thus, the first objective of the presented research was to develop an open-source 3D printable bioreactor with the photopolymer MED610TM that addresses the PC bioreactors fabrication and bone core height limitations. The second objective was to test the role of the MED610TM material on cell viability and determine a cleaning and sterilization protocol for MED610TM in cell and tissue culture applications. Finally, the third objective was to validate the 3D printed bioreactor in an ex vivo bovine trabecular bone study with mechanical stimulation by measuring the change in apparent elastic modulus over 21-days. Collectively, this thesis demonstrated that 3D printed MED610TM bioreactors cleaned and sterilized with a sonication and autoclave protocol are suitable for ex vivo bone organ culture and can replicate trends in trabecular bone apparent elastic modulus found in previous studies. Recommendations for next steps are provided including adjustments to the bioreactor design and continued biocompatibility and validation testing.