Liao Susan, Ngiam Michelle, Chan Casey K, Ramakrishna S
Division of Bioengineering, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 117576, Singapore.
Biomed Mater. 2009 Apr;4(2):025019. doi: 10.1088/1748-6041/4/2/025019. Epub 2009 Apr 6.
Mineralized type I collagen (collagen I) nanofibers and their nanofibril bundles make up the microstructure of natural bone tissue, which range from nanometers to micrometers. However, attempts to achieve this hierarchically assembled structure in vitro have been unsuccessful. In this study, we added osteonectin into the collagen I solution, either at a high or low weight ratio (osteonectin: collagen I = 1:30 or 1:90) before co-precipitation. Results indicated that spindle-like nano-hydroxyapatite (nano-HA) was deposited on collagen/osteonectin and pure osteonectin (control) groups. Furthermore, transmission electron microscope (TEM) and scanning electron microscope (SEM) results showed that the assembled mineralized fiber bundles were formed randomly at different levels from 50 nm, 250 nm to 1100 nm. However, when we replaced collagen I with collagen II, osteonectin addition did not induce the formation of mineralized fiber bundles. The participation of osteonectin in the assembly of the mineralized fibers could provide new insights into the novel mineralization function of osteonectin for bone development in vivo and advancing new biomimetic methods for bone graft applications.
矿化的I型胶原蛋白（胶原蛋白I）纳米纤维及其纳米纤维束构成了天然骨组织的微观结构，其范围从纳米到微米。然而，在体外实现这种分级组装结构的尝试一直没有成功。在本研究中，我们在共沉淀之前，以高或低重量比（骨粘连蛋白：胶原蛋白I = 1:30或1:90）将骨粘连蛋白添加到胶原蛋白I溶液中。结果表明，纺锤状纳米羟基磷灰石（纳米HA）沉积在胶原蛋白/骨粘连蛋白和纯骨粘连蛋白（对照）组上。此外，透射电子显微镜（TEM）和扫描电子显微镜（SEM）结果表明，组装的矿化纤维束在50nm、250nm至1100nm的不同水平上随机形成。然而，当我们用胶原蛋白II替代胶原蛋白I时，添加骨粘连蛋白并未诱导矿化纤维束的形成。骨粘连蛋白参与矿化纤维的组装可为骨粘连蛋白在体内骨发育中的新矿化功能以及推进骨移植应用的新仿生方法提供新的见解。
