Method: Hydrogel microbeads with sizes of 100-500 µm were fabricated with 1×106 hUCMSCs/mL. CPC was biofunctionalized with fibronectin (Fn) and Arg-Gly-Asp (RGD) for the first time. Four scaffolds were tested: CPC mixed with Fn, CPC mixed with RGD, CPC grafted with RGD, and CPC without Fn or RGD (control).
Result: The degradable microbeads released hUCMSCs at 7-day, and the released cells successfully attached to CPC. Biofunctionalizing CPC with Fn or RGD greatly improved cell attachment. CPC grafted with RGD had live cell density at 21-day of (1070±40) cells/mm2, higher than (115±20) cells/mm2 for CPC control (p<0.05). The released hUCMSCs underwent osteodifferentiation. Alkaline phosphatase gene expression increased from 1 at 1-day to 14.3 at 7-day (p<0.05). Osteocalcin increased from 1 at 1-day to 12.7 at 21-day (p<0.05). The released cells attached to CPC and synthesized bone minerals, with mineralization (nM) increasing from (0.2±0.1) at 7-day to (7.8±1.0) at 21-day (p<0.05).
Conclusion: Alginate-fibrin microbeads embedded in CPC surface were able to quickly release the hUCMSCs which attached to biofunctionalized CPC. Incorporating Fn and RGD into CPC greatly improved cell function, and CPC grafted with RGD had the fastest cell proliferation. The released cells on CPC differentiated into the osteogenic lineage and synthesized bone minerals. The novel biofunctionalized CPC with hUCMSC-encapsulating microbeads is promising to enhance bone regeneration in dental, craniofacial and orthopedic applications.
Keywords: Bioengineering, Bone, Composites, Tissue engineering and scaffold