Biomaterials and Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, Maryland 21201, USA.
Tissue Eng Part A. 2012 Apr;18(7-8):816-27. doi: 10.1089/ten.TEA.2011.0267. Epub 2011 Dec 9.
Tissue engineering approaches are promising to meet the increasing need for bone regeneration. Calcium phosphate cement (CPC) can be injected and self-set to form a scaffold with excellent osteoconductivity. The objectives of this study were to develop a macroporous CPC-chitosan-fiber construct containing alginate-fibrin microbeads encapsulating human umbilical cord mesenchymal stem cells (hUCMSCs) and to investigate hUCMSC release from the degrading microbeads and proliferation inside the porous CPC construct. The hUCMSC-encapsulated microbeads were completely wrapped inside the CPC paste, with the gas-foaming porogen creating macropores in CPC to provide for access to culture media. Increasing the porogen content in CPC significantly increased the cell viability, from 49% of live cells in CPC with 0% porogen to 86% of live cells in CPC with 15% porogen. The alginate-fibrin microbeads started to degrade and release the cells inside CPC at 7 days. The released cells started to proliferate inside the macroporous CPC construct. The live cell number inside CPC increased from 270 cells/mm(2) at 1 day to 350 cells/mm(2) at 21 days. The pore volume fraction of CPC increased from 46.8% to 78.4% using the gas-foaming method, with macropore sizes of approximately 100 to 400 μm. The strength of the CPC-chitosan-fiber scaffold at 15% porogen was 3.8 MPa, which approximated the reported 3.5 MPa for cancellous bone. In conclusion, a novel gas-foaming macroporous CPC construct containing degradable alginate-fibrin microbeads was developed that encapsulated hUCMSCs. The cells had good viability while wrapped inside the porous CPC construct. The degradable microbeads in CPC quickly released the cells, which proliferated over time inside the porous CPC. Self-setting, strong CPC with alginate-fibrin microbeads for stem cell delivery is promising for bone tissue engineering applications.
组织工程方法有望满足日益增长的骨再生需求。磷酸钙水泥（CPC）可注射并自凝形成具有优异骨传导性的支架。本研究的目的是开发一种含有藻酸盐-纤维蛋白微球的大孔 CPC-壳聚糖纤维构建体，该微球中包埋有人脐带间充质干细胞（hUCMSCs），并研究微球在 CPC 中的降解和细胞在多孔 CPC 构建体中的增殖。hUCMSC 包封的微球完全包裹在 CPC 糊剂内，气体发泡剂在 CPC 中形成大孔，以接触培养基。增加 CPC 中的成孔剂含量可显著提高细胞活力，从无成孔剂的 CPC 中活细胞的 49%增加到 15%成孔剂的 CPC 中的 86%。藻酸盐-纤维蛋白微球在第 7 天开始降解并释放 CPC 内的细胞。释放的细胞开始在大孔 CPC 构建体中增殖。CPC 内活细胞数量从第 1 天的 270 个细胞/mm(2)增加到第 21 天的 350 个细胞/mm(2)。使用气体发泡法，CPC 的孔体积分数从 46.8%增加到 78.4%，大孔尺寸约为 100 至 400μm。15%成孔剂的 CPC-壳聚糖纤维支架的强度为 3.8MPa，接近松质骨报道的 3.5MPa。总之，开发了一种新型的气体发泡大孔 CPC 构建体，其中含有可降解的藻酸盐-纤维蛋白微球，包封了 hUCMSCs。细胞在多孔 CPC 构建体中具有良好的活力。CPC 中的可降解微球迅速释放细胞，这些细胞随时间在多孔 CPC 内增殖。用于干细胞递送的自凝固、强 CPC 与藻酸盐-纤维蛋白微球结合有望用于骨组织工程应用。
