Nanomechanics of UV irradiated collagen fibrills

胶原蛋白以细长原纤维的形式具有特殊的特性，是人体的主要结构蛋白。由于其复杂的层次结构，胶原蛋白具有非常高的（极限）抗拉强度。因此，胶原蛋白增加了皮肤、肌腱、血管结扎、器官或骨骼的拉伸强度和弹性。在技术上，胶原蛋白是细胞培养的重要底物，在组织工程中起支架作用。在这些例子中，胶原蛋白的力学特性起着突出的作用。胶原蛋白的力学性能是由内部交联决定的。在生物体中，交联发生在原纤维的合成和组装过程中。然而，外部影响，如紫外线（UV）辐射或温度处理也会影响机械性能，因为会产生额外的交联。长期的治疗可能会导致由于蛋白质水解而导致的衰弱。然而，在单个纤维的尺度上，紫外线辐射和温度的影响尚不清楚。因此，处理后的胶原蛋白的纳米力学应借助原子力显微镜进行研究。共聚焦拉曼光谱将有助于空间分辨化学分析。该项目旨在证明I型胶原蛋白的纳米力学性能可以通过紫外线照射和温度处理在可控的方式下进行修饰。从更长远的角度来看，结果将有助于胶原基质或支架具有可控的机械性能。

Collagen in the form of elongated fibrils possesses exceptional properties and is the main structural protein of the human body. Owing to its complex and hierarchical structure collagen has a very high (ultimate) tensile strength. Thus, collagen adds tensile strength and resilience to skin, tendon, vascular ligature, organs, or bone. In technology collagen is an important substrate in cell culture and serves as a scaffold in tissue engineering. In these examples, the mechanical properties of collagen play a prominent role. The mechanical properties of collagen are determined by internal cross-linking. In an organism, cross-linking occurs during synthesis and assembly of the fibrils. External influence, however, such as ultraviolet (UV) radiation or temperature treatment also affect the mechanical properties because additional cross-links are created. Extended treatment may lead to a weakening due to proteolysis. However, on the scale of individual fibrils it is not clear which influence UV radiation and temperature have. Thus, the nanomechanics of treated collagen shall be investigated with the aid of an atomic force microscope. Confocal Raman spectroscopy shall contribute to a spatially resolved chemical analysis. The project aims to show that the nanomechanical properties of collagen type I can be modified in a controlled manner with UV irradiation and temperature treatment. On a longer perspective the results shall contribute to collagen matrices or scaffolds with controlled mechanical properties.