Xpand Biotechnology BV, Bilthoven, The Netherlands.
Acta Biomater. 2013 Dec;9(12):9401-13. doi: 10.1016/j.actbio.2013.07.026. Epub 2013 Jul 31.
In bone tissue regeneration, certain polymer and calcium-phosphate-based composites have been reported to enhance some biological surface phenomena, facilitating osteoinduction. Although the crucial role of inorganic fillers in heterotopic bone formation by such materials has been shown, no reports have been published on the potential effects the polymer phase may have. The present work starts from the assumption that the polymer molecular weight regulates the fluid uptake, which determines the hydrolysis rate and the occurrence of biological surface processes. Here, two composites were prepared by extruding two different molecular weight L/D,L-lactide copolymers with calcium phosphate apatite. The lower molecular weight copolymer allowed larger fluid uptake in the composite thereof, which was correlated with a higher capacity to adsorb proteins in vitro. Further, the large fluid absorption led to a quicker composite degradation that generated rougher surfaces and enhanced ion release. Following intramuscular implantation in sheep, only the composite with the lower molecular weight polymer could induce heterotopic bone formation. Besides influencing the biological potential of composites, the molecular weight also regulated their viscoelastic behaviour under cyclic stresses. The results lead to the conclusion that designing biomaterials with appropriate physico-chemical characteristics is crucial for bone tissue regeneration in mechanical load-bearing sites.
在骨组织再生中，已经有报道称某些聚合物和钙磷基复合材料能够增强某些生物表面现象，促进成骨诱导。虽然已经证明了这些材料中无机填料在异位骨形成中的关键作用，但尚未有关于聚合物相可能产生的潜在影响的报道。本工作从聚合物分子量调节流体吸收的假设出发，而流体吸收决定了水解速率和生物表面过程的发生。在这里，通过挤出两种不同分子量的 L/D,L-丙交酯共聚物与磷酸钙磷灰石，制备了两种复合材料。较低分子量的共聚物允许复合材料中更大的流体吸收，这与体外更大的蛋白质吸附能力相关。此外，大的流体吸收导致更快的复合材料降解，产生更粗糙的表面并增强离子释放。在绵羊的肌肉内植入后，只有具有较低分子量聚合物的复合材料才能诱导异位骨形成。除了影响复合材料的生物学潜力外，分子量还调节了它们在循环应力下的粘弹性行为。结果得出结论，设计具有适当物理化学特性的生物材料对于机械承重部位的骨组织再生至关重要。
