Novel functional materials based on self-assembled protein nanofibers (PNNF): Degradation dynamics of PNNFs/hybrid PNNFs and creation of PNNF/hybrid PNNF micro-scaffolds (step 2)

蛋白质纳米纤维具有优异的生物相容性和机械强度，在材料科学和生物医学工程中具有很大的应用潜力。在成功完成的第一个项目步骤中，我们i)创建了由两种不同血浆蛋白组成的新型杂化PNNF(hPNNF.)，ii)开发了PNNF自组装模型，该模型解释了观察到的实验结果并允许预测新的PNNF，iii)创建了在溶液中稳定至少4周的单个PNNF，以及iv)获得了所需的PNNF机械硬度，导致在高影响因子期刊上发表文章。第一个项目步骤的结果为第二个项目步骤奠定了良好的基础。第二个步骤侧重于提高对PNNF和MS降解的知识。这有助于未来设计生物材料的稳定性以满足所需的组织再生动力学。我们将验证两个假设：第一，通过微接触印刷(μCP)方法，通过逐层(LBL)的方法，将PNF和新型杂化PNNF构建成MSS；第二，基于对PNNF降解的了解，可以创建具有期望目标降解的MSS。因此，项目第二步的研究目的是：i)了解目前未知的MSS构建块(PNNFs/hPNF.)的降解机理；ii)应用新的策略来基于自组装的PNNF/hPNFs来构建新型MSS。为此，我们的第二步研究的目的是：i)了解目前未知的MSS构建块(PNF./hPNF.)的降解机理；ii)应用新的策略基于自组装的PNNF/hPNFs来构建新型MSS。为此，我们的研究目标是：我们将利用湿态AFM和QCM结合骨再生条件初步研究PNNF和hPNNF的降解动力学。这些实验的结果将使我们能够了解PNNF的降解机制以及第二个蛋白质在hPNNF中的影响以及PNNF/hPNNF的尺寸，这对于定制基于PNNF/hPNNF的MSS的降解是重要的。接下来，我们将创建基于PNNF/hPNNF的单层和双层，作为使用LBL浸渍涂层来制备3D MS的重要中间步骤。最后，我们将结合LBL和μCP方法来创建3D-MS，目的是通过PNNF/hPNNF尺寸的选择以及MS结构的选择来了解和调整MS的降解特性。在第三个项目步骤中(最后两年)，我们将定制MS的降解、力学性能，从而，细胞对MS的反应。我们预计，预测的结果将显著促进对PNNF的认识和理解，并通过PNNF和MS的特性的灵活性，对MSS作为组织再生生物材料的应用产生相当大的影响。

Due to their outstanding biocompatibility and mechanical strength, protein nanofibers (PNNFs) have a high potential for applications in materials science and biomedical engineering. In this stepwise project (3 project steps with 2 years duration each), we aim towards understanding PNNF formation mechanisms and to apply this knowledge by creating novel PNNF based micro-scaffolds (MS) as building blocks for larger structures in tissue regeneration or drug delivery.In the successfully completed first project step, we i) created novel hybrid PNNFs (hPNNFs) consisting of two different plasma proteins, ii) developed a model for PNNF self-assembly that explains the observed experimental results and allows predictions for new PNNFs, iii) created single PNNFs that are stable in solution for at least 4 weeks, and iv) achieved the desired PNNF mechanical stiffness, leading to publications in high impact factor journals. The results of the first project step lay a promising foundation for the second project step.This second step focuses on the advancement of knowledge of PNNF and MS degradation. It contributes to the future goal of designing the biomaterials’ stability to required regeneration kinetics of tissues. We will test two hypotheses: first, that MSs can be fabricated from PNNFs and novel hybrid PNNFs by layer-by-layer (LBL) with micro-contact printing (μCP) approaches, and second, that based on the understanding of the PNNF degradation, MSs with desired target degradation can be created.Our research aims of project step 2 are, therefore, to i) understand the currently unknown degradation mechanisms of the MSs building blocks (PNNFs/hPNNFs), ii) to apply new strategies to fabricate novel MSs based on the self-assembled PNNFs/hPNNFs.To this end, we will initially investigate the PNNF’s and hPNNF’s degradation dynamics using wet state AFM and QCM considering bone regeneration conditions. The results from these experiments will enable us to understand the PNNF degradation mechanism and the impact of the second protein in hPNNFs and of the PNNF/hPNNF dimensions, which are important for tailoring the degradation of the PNNF/hPNNF based MSs. Next, we will create PNNF/hPNNF based single and bilayers, as important intermediate step to fabricate 3D MSs, using LBL dip coating.Finally, we will create 3D-MSs by combining LBL and μCP approaches with the aim to understand and adjust the MS’ degradation properties through the choice of PNNF/hPNNF dimensions as well as the choice of the MS structure.In the third project step (last 2 years), we will tailor the degradation, mechanical properties and, thus, the cellular response to the MSs.We expect that the projected results will significantly advance the knowledge and understanding of PNNFs and have a considerable impact on the application of MSs as biomaterials for tissue regeneration through the flexibility of the PNNF’s and MS’ properties.