家蚕丝素蛋白纳米纤维调控及其在组织修复材料中应用-regulation of fibroin nanofiber and its application in tissue repair materials.docx

家蚕丝素蛋白纳米纤维的调控及其在生物组织修复材料中的应用英文摘要Regulation of silk fibroin nanofibrils and application in tissue repairing biomaterialsAbstractThe micro/nanoscale topography of scaffolds plays an important role in controlling the growth, proliferation and differentiation of cells and the reconstruction of the extracellular matrix (ECM) in tissue engineering. Mimicking the micro/nanoscale structure of the ECM to fabricate the microenvironment for the growth of cells and tissues is a new direction for fabricating the tissue repairing substrates. Nanofibril is the fundamental unit of living systems. Nanofibrous materials have the similar microstructures with the ECM, providing more suitable enviroment for tissue engineering. Silk fiber is one of the strongest and toughest biological materials with hierarchical structures where nanofibril with size of below 20 nm is crifical factor in determing the excellent mechanical properties. Although silk nanofibrils have been found in natural and regenerated silk solutions, there is no effective way to actively control nanofibril formation in aqueous solution, which limits the application of silk materials in tissue engineering.Here we show a simple but effective method to prepare silk nanofibrils by regulating silk self-assembly process. Through a repeated drying-dissolving process, silk fibroin solution composed of metastable nanoparticles was firstly prepared and then used to reassemble nanofibrils with different sizes and contents of β-sheet under various temperatures and concentrations. These nanofibrils have similar morphology with that in natural fibers, providing a suitable unit for further assemble hierarchical structure in vitro. Several important issues such as the relationships between silk nanofibrils, secondary conformations and viscosity are also elucidated, giving a new insight into the self-assembly process.Then, through different post-processing methods, we further regulate the secondary structures and mechanical properties of