University of Illinois at Urbana-Champaign, IL 61801, USA.
Acta Biomater. 2011 Jan;7(1):16-30. doi: 10.1016/j.actbio.2010.07.012. Epub 2010 Jul 21.
Repair of load-bearing defects resulting from disease or trauma remains a critical barrier for bone tissue engineering. Calcium phosphate (CaP) scaffolds are among the most extensively studied for this application. However, CaPs are reportedly too weak for use in such defects and, therefore, have been limited to non-load-bearing applications. This paper reviews the compression, flexural and tensile properties of CaPs and CaP/polymer composites for applications in bone replacement and repair. This review reveals interesting trends that have not, to our knowledge, previously been reported. Data are classified as bulk, scaffolds, and composites, then organized in order of decreasing strength. This allows for general comparisons of magnitudes of strength both within and across classifications. Bulk and scaffold strength and porosity overlap significantly and scaffold data are comparable to bone both in strength and porosity. Further, for compression, all composite data fall below those of the bulk and most of the scaffold. Another interesting trend revealed is that strength decreases with increasing β-tricalcium phosphate (β-TCP) content for CaP scaffolds and with increasing CaP content for CaP/polymer composites. The real limitation for CaPs appears not to be strength necessarily, but toughness and reliability, which are rarely characterized. We propose that research should focus on novel ways of toughening CaPs and discuss several potential strategies.
修复因疾病或创伤导致的承重缺陷仍然是骨组织工程的一个关键障碍。钙磷酸盐 (CaP) 支架是此类应用中研究最多的支架之一。然而，据报道，CaP 太弱，无法用于此类缺陷，因此仅限于非承重应用。本文综述了用于骨替代和修复的 CaP 和 CaP/聚合物复合材料的压缩、弯曲和拉伸性能。本综述揭示了一些有趣的趋势，这些趋势据我们所知以前尚未报道过。数据分为块状、支架和复合材料，然后按强度递减的顺序进行组织。这允许在分类内和跨分类进行强度的幅度的一般比较。块状和支架的强度和孔隙率有很大的重叠，支架数据在强度和孔隙率方面与骨骼相当。此外，对于压缩，所有复合材料数据均低于块状和大多数支架的数据。另一个有趣的趋势是，对于 CaP 支架，CaP 中的β-磷酸三钙 (β-TCP) 含量增加会导致强度降低，而对于 CaP/聚合物复合材料，CaP 含量增加会导致强度降低。CaP 的真正限制似乎不是强度，而是韧性和可靠性，而韧性和可靠性很少被表征。我们建议研究应集中在增强 CaP 的新方法上，并讨论了几种潜在的策略。
