一种新型特异性聚集诱导发光（AIE）材料用于可视化监测成骨细胞转化程度和骨折不愈合的早期诊断研究

由于缺乏对成骨细胞分化程度的检测手段，所以目前骨折延迟愈合和不愈合还不能早期诊断。本课题组合成了一种新型聚合诱导发光聚合物：PTB-EDTA，使成骨分化程度的可视化监测成为可能。前期研究发现该聚合物对钙离子具有高亲和力，在前成骨细胞MC3T3-E1向成骨分化时，其可通过细胞的胞吞作用进入溶酶体，在成骨细胞内选择性富集，逐渐“点亮”细胞，而细胞活性、碱性磷酸酶和钙结节的形成不受影响。另外研究还发现该聚合物特异性较强，不能“点亮”其他细胞及未分化的前成骨细胞。考虑到骨髓间充质干细胞(BMSCs)也能分化为成骨细胞，本项目拟继续研究BMSCs在成骨分化时荧光强度变化特征，观察成骨分化程度与荧光强度变化是否成正相关，探讨将该聚合物的荧光强度作为成骨分化程度指标的可能性。另外用该材料在动物体内研究骨发育特点及骨折愈合和不愈合模型中的骨代谢特点，为骨折不愈合和延迟愈合提供新的诊断标准。

Due to the lack of detection methods for the differentiation degree of osteoblasts, the delayed union and nonunion of fracture can not be diagnosed in the early stage. In this project, we synthesized a new polymer, PTB-EDTA, which makes it possible to monitor the degree of osteogenic differentiation. Previous studies found that the polymer has high affinity for calcium ions. When the pre-osteoblasts MC3T3-E1 differentiate into osteoblasts, the polymer crossed the cell membrane through endocytosis and enriched in lysosomes, leading to its enrichment in osteoblasts, and “lighting up” the cells gradually, while the activity of cells, ALP and the formation of calcium nodules were not affected. In addition, it was found that the polymer was highly specific and could not “light up” other cells and undifferentiated pre-osteoblasts. Considering that BMSCs can also differentiate into osteoblasts, this project intends to study the characteristics of fluorescence imaging of BMSCs in osteogenic differentiation, observe whether osteogenic differentiation degree is positively correlated with fluorescence intensity, explore the possibility of using the fluorescence intensity as an indicator of the degree of osteogenic differentiation. In addition, this material will be used to study the characteristics of bone development and bone metabolism in fracture healing and nonunion.