Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland, Dental School, 650 West Baltimore Street, Baltimore, Maryland 21201, USA.
J Biomed Mater Res A. 2010 Jul;94(1):223-33. doi: 10.1002/jbm.a.32665.
Calcium phosphate cement (CPC) is osteoconductive and moldable, and it can conform to complex cavity shapes and set in situ to form hydroxyapatite. Chitosan could increase the strength and toughness of CPC, but there has been no investigation on recombinant human bone morphogenic protein-2 (rhBMP-2) delivery via CPC-chitosan composite and its effect on osteogenic induction of cells. The objective of this research was to investigate the mechanical properties and osteoblastic induction of MC3T3-E1 cells cultured on CPC-containing chitosan and rhBMP-2. Cell viability for CPC with chitosan and rhBMP-2 was comparable with that of control CPC, whereas the CPC-chitosan composite was stronger and tougher than CPC control. After 14 days, osteoblastic induction was quantified by measuring alkaline phosphatase (ALP) activity. ALP (mean +/- SD; n = 6) of cells seeded on conventional CPC without rhBMP-2 was (143 +/- 19) (mM pNpp/min)/(mug DNA). The addition of chitosan resulted in an ALP of 161 +/- 27. Further addition of rhBMP-2 to the CPC-chitosan composite increased the ALP to 305 +/- 111 (p < 0.05). All ALP activity on CPC composites was significantly higher when compared with the 10.0 +/- 3.3 of tissue culture polystyrene (p < 0.05). Flexural strength of CPC containing 15% (mass fraction) chitosan was 19.8 +/- 1.4 MPa, which is more than double the 8.0 +/- 1.4 MPa of conventional CPC (p < 0.05). The addition of chitosan to CPC increased the fracture toughness from 0.18 +/- 0.01 MPa.m(1/2) to 0.23 +/- 0.02 MPa.m(1/2) (p < 0.05). The relatively high strength, self-hardening CPC-chitosan composite scaffold is promising as a moderate load-bearing matrix for bone repair, with potential to serve as an injectable delivery vehicle for osteoinductive growth factors to promote osteoblastic induction and bone regeneration. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.
磷酸钙水泥 (CPC) 具有骨传导性和可模塑性，可适应复杂的腔隙形状，并原位形成羟基磷灰石。壳聚糖可以提高 CPC 的强度和韧性，但目前还没有关于通过 CPC-壳聚糖复合材料递送重组人骨形态发生蛋白-2 (rhBMP-2) 及其对细胞成骨诱导影响的研究。本研究的目的是研究含壳聚糖的 CPC 培养的 MC3T3-E1 细胞的力学性能和成骨诱导。含壳聚糖和 rhBMP-2 的 CPC 的细胞活力与对照 CPC 相当，而 CPC-壳聚糖复合材料比对照 CPC 更强韧。14 天后，通过测量碱性磷酸酶 (ALP) 活性来定量成骨诱导。未添加 rhBMP-2 的常规 CPC 上接种细胞的 ALP（平均值 +/- SD；n = 6）为（143 +/- 19）（mM pNpp/min）/（mug DNA）。添加壳聚糖可使 ALP 达到 161 +/- 27。进一步向 CPC-壳聚糖复合材料中添加 rhBMP-2，可将 ALP 提高至 305 +/- 111（p < 0.05）。与组织培养聚苯乙烯的 10.0 +/- 3.3 相比，所有 CPC 复合材料上的 ALP 活性均显著升高（p < 0.05）。含 15%（质量分数）壳聚糖的 CPC 的弯曲强度为 19.8 +/- 1.4 MPa，是常规 CPC 的 8.0 +/- 1.4 MPa 的两倍多（p < 0.05）。向 CPC 中添加壳聚糖可使断裂韧性从 0.18 +/- 0.01 MPa.m(1/2) 提高到 0.23 +/- 0.02 MPa.m(1/2)（p < 0.05）。相对较高的强度、自硬化的 CPC-壳聚糖复合材料支架有望成为中等承重骨修复基质，具有作为骨诱导生长因子注射递送载体的潜力，以促进成骨诱导和骨再生。（c）2010 年 Wiley 期刊，Inc. J Biomed Mater Res，2010。
