Umrath Felix, Schmitt Lukas-Frank, Kliesch Sophie-Maria, Schille Christine, Geis-Gerstorfer Jürgen, Gurewitsch Elina, Bahrini Kathleen, Peters Fabian, Reinert Siegmar, Alexander Dorothea
Department of Oral and Maxillofacial Surgery, University Hospital Tübingen, 72076 Tübingen, Germany.
Department of Orthopedic Surgery, University Hospital Tübingen, 72076 Tübingen, Germany.
J Funct Biomater. 2023 Aug 16;14(8):427. doi: 10.3390/jfb14080427.
Autologous bone transplantation is still considered as the gold standard therapeutic option for bone defect repair. The alternative tissue engineering approaches have to combine good hardiness of biomaterials whilst allowing good stem cell functionality. To become more useful for load-bearing applications, mechanical properties of calcium phosphate materials have to be improved. In the present study, we aimed to reduce the brittleness of β-tricalcium phosphate (β-TCP). For this purpose, we used three polymers (PDL-02, -02a, -04) for coatings and compared resulting mechanical and degradation properties as well as their impact on seeded periosteal stem cells. Mechanical properties of coated and uncoated β-TCP scaffolds were analyzed. In addition, degradation kinetics analyses of the polymers employed and of the polymer-coated scaffolds were performed. For bioactivity assessment, the scaffolds were seeded with jaw periosteal cells (JPCs) and cultured under untreated and osteogenic conditions. JPC adhesion/proliferation, gene and protein expression by immunofluorescent staining of embedded scaffolds were analyzed. Raman spectroscopy measurements gave an insight into material properties and cell mineralization. PDL-coated β-TCP scaffolds showed a significantly higher flexural strength in comparison to that of uncoated scaffolds. Degradation kinetics showed considerable differences in pH and electrical conductivity of the three different polymer types, while the core material β-TCP was able to stabilize pH and conductivity. Material differences seemed to have an impact on JPC proliferation and differentiation potential, as reflected by the expression of osteogenic marker genes. A homogenous cell colonialization of coated and uncoated scaffolds was detected. Most interesting from a bone engineer's point of view, the PDL-04 coating enabled detection of cell matrix mineralization by Raman spectroscopy. This was not feasible with uncoated scaffolds, due to intercalating effects of the β-TCP material and the JPC-formed calcium phosphate. In conclusion, the use of PDL-04 coating improved the mechanical properties of the β-TCP scaffold and promoted cell adhesion and osteogenic differentiation, whilst allowing detection of cell mineralization within the ceramic core material.
自体骨移植仍然被视为骨缺损修复的金标准治疗选择。替代的组织工程方法必须结合生物材料良好的坚韧性，同时允许干细胞具有良好的功能。为了在承重应用中更有用，磷酸钙材料的机械性能必须得到改善。在本研究中，我们旨在降低β-磷酸三钙（β-TCP）的脆性。为此，我们使用了三种聚合物（PDL-02、-02a、-04）进行涂层，并比较了所得的机械性能和降解性能以及它们对接种的骨膜干细胞的影响。分析了涂覆和未涂覆的β-TCP支架的机械性能。此外，对所用聚合物和聚合物涂覆的支架进行了降解动力学分析。为了进行生物活性评估，将支架接种下颌骨膜细胞（JPCs），并在未处理和成骨条件下培养。分析了JPC的粘附/增殖、通过对包埋支架进行免疫荧光染色的基因和蛋白质表达。拉曼光谱测量深入了解了材料性能和细胞矿化情况。与未涂覆的支架相比，PDL涂覆的β-TCP支架显示出显著更高的弯曲强度。降解动力学表明，三种不同聚合物类型在pH值和电导率方面存在相当大的差异，而核心材料β-TCP能够稳定pH值和电导率。材料差异似乎对JPC的增殖和分化潜能有影响，这通过成骨标记基因的表达得到反映。检测到涂覆和未涂覆支架上的细胞均匀殖民化。从骨工程师的角度来看，最有趣的是，PDL-04涂层能够通过拉曼光谱检测细胞基质矿化。对于未涂覆的支架来说，这是不可行的，因为β-TCP材料和JPC形成的磷酸钙存在嵌入效应。总之，使用PDL-04涂层改善了β-TCP支架的机械性能，促进了细胞粘附和成骨分化，同时允许检测陶瓷核心材料内的细胞矿化。
