Fabrication of electrospun fibre mats with defined geometry and load profile

子项目3(SP3)的重点是用聚己内酯(PCL)通过静电纺丝制造纤维毡。这些纤维垫应具有分级的力学和几何性能，以及必须承受自然载荷条件。制造用于活体研究的纤维垫的方法受到支架机械性能不适当的影响。这个问题将在第二个资金期通过将溶液静电纺丝和熔体静电纺丝相结合来解决。这种组合允许制造具有适当机械性能的更大尺寸的纤维。它使具有承重结构的支架与模仿天然细胞外基质的结构相结合，以增强细胞的渗透。最终得到的支架由微米和纳米纤维组成，增加了比表面积。已知比表面影响细胞黏附，这将在SP1中进行研究。BM-MSCs的细胞黏附力将通过原子力显微镜(AFM)测量。第一个资助期的研究表明，聚合物的结晶度是对机械性能有很大影响的因素之一(SP4的结果)。改变收集器的转速可以影响结晶度。它随着速度的增加而增加。这种效果以及与壳聚糖-g-聚己内酯(SP4)的混合将在下一个资助期用于定制支架的机械性能。此外，还将与SP6合作研究降解动力学。在这里，将分析质量损失以及分子结构(拉曼光谱)的变化，以进一步研究降解过程。这个子项目的工作计划将产生一个脚手架，该脚手架是根据小动物和大动物的负载条件量身定做的。该支架的性能在动物实验中进行了评估(SP8)。

Subproject 3 (SP3) focuses on the fabrication of fiber mats from polycaprolactone (PCL) via electrospinning. These fiber mats should have graded mechanical and geometric properties as well as have to withstand the native loading conditions. Approaches to fabricate fiber mats for in vivo studies in rats or sheep suffered from inappropriate mechanical properties of the scaffold. This issue is going to be solved in the second funding period by combining solution electrospinning with melt electrospinning. This combination allows for the fabrication of larger fiber sizes with appropriate mechanical properties. It enables the fabrication of scaffolds with load-bearing structures combined with structures mimicking the native extracellular matrix to enhance cell infiltration. The resulting scaffolds consists of a combination of micro- and nanofibers, which increases the specific surface. The specific surface is known to influence cell attachment, which is going to be investigated in SP 1. Cell adhesion forces of BM-MSCs will be measured via atomic force microscopy (AFM). Studies in the first funding period have shown the crystallinity of the polymer being one of the factors with high impact on the mechanical properties (results of SP4). The crystallinity can be influenced by changing the rotating velocity of the collector. It increases with increasing velocity. This effect as well as the blending with chitosan-g-polycaprolactone (SP4) will be used to tailor the mechanical properties of the scaffold during the next funding period. In addition, the degradation kinetics will be investigated in cooperation with SP 6. Here, mass loss as well as changes in the molecular structure (Raman spectroscopy) will be analyzed to further investigate the degradation process. The working plan of this subproject will result in a scaffold, which is tailored to the loading conditions in small and large animals. The performance of this scaffold is assessed in animal trials (SP8).