Department of Trauma-, Hand- and Reconstructive Surgery, Saarland University, Kirrberger Str. 1, D-66421 Homburg/Saar, Germany.
Biomed Mater. 2017 Sep 25;12(5):055007. doi: 10.1088/1748-605X/aa7e80.
Despite the growing knowledge on the mechanisms of fracture healing, bone defects often do not heal in a timely manner. Clinically, tricalcium phosphate (TCP) bone substitutes are used to fill bone defects and promote bone healing. However, the degradation rate of these implants is often too slow for sufficient bone replacement. The use of calcium phosphate material with the crystalline phase CaK/Na containing different amounts of di- and metaphosphates may overcome this problem, because these materials show an accelerated degradation. Therefore, we generated alkaline substituted Ca-P scaffolds with different amounts of ortho-, di- and metaphosphates. The degradation of these materials was analyzed in TRIS-HCl buffer solution in vitro. Moreover, we measured the compressive strength and porosity of the scaffolds by micro-CT analysis. The biocompatibility of the scaffolds was evaluated in vivo in the mouse dorsal skinfold chamber by means of intravital fluorescence microscopy and histology. We found that higher amounts of incorporated di- and metaphosphates increase the degradation rate and compressive strength of the scaffolds without inducing a stronger leukocytic inflammatory host tissue reaction after implantation. Histological analyses confirmed the good biocompatibility of the scaffolds containing di- and metaphosphates. In summary, this study demonstrates that the compressive strength and degradation rate of Ca-P scaffolds can be improved by incorporation of di- and metaphosphates without affecting their good biocompatibility. Hence, this material modification may be particularly beneficial for the treatment of metaphyseal bone defects in weight bearing locations.
尽管人们对骨折愈合机制的了解不断增加，但骨缺损仍常常不能及时愈合。临床上，磷酸三钙（TCP）骨替代物被用于填充骨缺损并促进骨愈合。然而，这些植入物的降解速度通常太慢，无法进行充分的骨替代。使用含有不同量的二磷酸盐和偏磷酸盐的具有晶相 CaK/Na的磷酸钙材料可能会克服这个问题，因为这些材料显示出加速降解。因此，我们生成了具有不同量的正、二和偏磷酸盐的碱性取代 Ca-P 支架。通过体外在 TRIS-HCl 缓冲溶液中分析了这些材料的降解情况。此外，我们通过微 CT 分析测量了支架的抗压强度和孔隙率。通过体内荧光显微镜和组织学分析，在小鼠背部皮褶室中评估了支架的生物相容性。我们发现，掺入的二磷酸盐和偏磷酸盐越多，支架的降解速率和抗压强度就越高，而在植入后不会引起更强的白细胞炎症宿主组织反应。组织学分析证实了含有二磷酸盐和偏磷酸盐的支架具有良好的生物相容性。总之，这项研究表明，通过掺入二磷酸盐和偏磷酸盐可以提高 Ca-P 支架的抗压强度和降解速率，而不会影响其良好的生物相容性。因此，这种材料改性可能特别有益于承重部位的干骺端骨缺损的治疗。
