Chitosan Fiberbased Threedimensional Hybrid Scaffolds for Bone Tissue Engineering

在第一阶段的资助中，成功地开发了由壳聚糖微纤维和纳米纤维制成的新型NSN-杂化支架，这些支架是在具有一定孔隙率的分级简单支架结构中构建的。体外实验检测其作为骨支架材料的适宜性。基于第一阶段资助的广泛和有希望的结果，在拟议的第二阶段资助中，将开发出新颖的、结构复杂的、具有局部可调节孔隙率的功能化NSN混合支架，以生成与骨组织具有相同结构和材料组成的支架。因此，主要目标是开发纺织技术解决方案，以实现这种复合胶原蛋白涂层的NSN-杂化支架，具有局部可调节的孔梯度，并具有数值可定义和可重复的性能。为此，应通过计算机系统模拟复杂NSN结构的性能，以便预测所应用的纤维类型、制造参数和涂层与由此产生的结构和孔隙率之间的关系，以及驱动NSN-混合支架的设计指南。必须建立使用材料模型中开发的算法的连续工艺链，允许定义和预置制造复杂结构的NSN-Hybridge支架，从而将试错尝试降至最低。必须开发一种新的定量方法，以统计有效的方式分析孔径梯度。应用胶原蛋白涂层来产生孔梯度，这也有利于细胞响应，需要进一步研究影响NSN-Hybridge支架涂层的参数。NSN杂化支架的靶向矿化和生长因子(BMP-2，或VEGF)在纳米纤维尺度上的功能化，旨在进一步改善细胞的黏附、增殖和分化。通过改变纤维类型和灭菌方法来研究NSN支架的吸收动力学。通过荧光标记NSN杂化支架内的壳聚糖纤维，将研究破骨细胞存在下的生物吸收，以得出关于体内降解行为的结论。最适合骨细胞的支架功能化将通过单一和联合培养的细胞培养实验来确定。在为体内研究做准备时，将检测NSN支架对血管形成的影响。作为这项研究工作的结果，将提供一种NSN模型支架，该支架有望用于未来的体内实验。

Novel NSN-Hybrid-Scaffolds made of chitosan micro- and nanofibres which are constructed in hierarchically simple scaffold structures with defined porosity, were successfully developed in the first stage of funding. Their suitability as a 3D-scaffold structure for bone TE was tested in vitro. Based on the extensive and promising results of the first stage of funding novel, complexly structured and functionalized NSN-Hybrid-Scaffolds with local adjustable porosities are to be developed in the proposed second stage of funding, in order to generate a scaffold, which has the same structure and material composition as the bone tissue. Therefore, the main objective is the development of textile technological solutions for the realization of such complex collagen-coated NSN-Hybrid-Scaffolds with local adjustable pore gradients and both numerically definable and reproducible properties. For this purpose, the properties of the complex NSN structures shall be modelled by means of computer systems in order to predict the relationships between the applied fibre types, fabrication parameters and coatings and the thus resulting structure and porosity as well as to drive the design guidelines for NSN-Hybrid-Scaffolds. A continuous process chain that uses the algorithms developed in the material model must be established, allowing the defined and pre-set fabrication of complexly structured NSN-Hybridscaffolds and thus minimizing trial & error attempts. A new quantitative method must be developed to analyse the pore size gradients in a statistically valid way. The application of collagen coating for the generation of pore gradients, which is also advantageous for cell response, requires a further study of the influential parameters in the coating of NSN-Hybridscaffolds. A further improvement in cell adhesion, proliferation and differentiation is intended by the targeted mineralization of NSN-Hybrid-Scaffolds and functionalization with growth factors (BMP-2, or VEGF) on the nanofibre-scale. The absorption kinetics of the NSN-Scaffolds will be investigated by varying the fibre types and sterilization methods. By means of fluorescence labelling of the chitosan fibres within the NSN-Hybrid-Scaffolds the bioresorption will be studied in the presence of bone resorbing osteoclasts to obtain conclusions regarding the in vivo degradation behaviour. The most suitable scaffold functionalization for bone cells will be determined by cell culture experiments in mono- and co-cultures. In preparation for in vivo studies the influence of the NSN-Scaffolds on the formation of blood vessels will be examined. As a result of this research work a NSN model scaffold shall be provided, which seems promising for future in vivo experiments.