Perfusion directed 3D mineral formation within cell-laden hydrogels

摘要

Despite the promise of stem cell engineering and the new advances in bioprinting technologies, one ofthe major challenges in the manufacturing of large scale bone tissue scaffolds is the inability to perfusenutrients throughout thick constructs. Here, we report a scalable method to create thick, perfusablebone constructs using a combination of cell-laden hydrogels and a 3D printed sacrificial polymer.Osteoblast-like Saos-2 cells were encapsulated within a gelatin methacrylate (GelMA) hydrogel and3D printed polyvinyl alcohol pipes were used to create perfusable channels. A custom-built bioreactorwas used to perfuse osteogenic media directly through the channels in order to induce mineraldeposition which was subsequently quantified via micro-CT. Histological staining was used to verifymineral deposition around the perfused channels, while COMSOL modeling was used to simulateoxygen diffusion between adjacent channels. This information was used to design a scaled-upconstruct containing a 3D array of perfusable channels within cell-laden GelMA. Progressive matrixmineralization was observed by cells surrounding perfused channels as opposed to random mineraldeposition in static constructs. Micro-CT confirmed that there was a direct relationship betweenchannel mineralization within perfused constructs and time within the bioreactor. Furthermore, thescalable method presented in this work serves as a model on how large-scale bone tissue replacementconstructs could be made using commonly available 3D printers, sacrificial materials, and hydrogels.