| Common stimuli-responsive hydrogels are limited in their application in biomedical applications due to gelation conditions,especially in scenarios involving encapsulated cells.This thesis provides a well-adapted,broad-spectrum responsive peptide-based nanomaterial that is investigated in three parts: peptide molecular design,material construction and application.Through a combination of computational simulations and experimental results,three candidate peptides were screened and a peptide molecule with good solubility in water was finally selected.It is noteworthy that the molecular dynamics simulations were not used as an aid to demonstrate the mechanism,but to guide the design of the peptide molecules and the construction of the peptide-based materials,and the results of the computational simulations were verified to be reasonable.Rheological experiments were used to demonstrate that peptide molecules can be self-assembled in water by a variety of initiators and that the type of initiator affects the viscoelasticity of peptide hydrogels.Field emission scanning electron microscopy and transmission electron microscopy present nanoscale changes in the formation of three-dimensional fibrous network structures from flexible fibres by self-assembled peptides.Circular dichroism and Fourier infrared broad spectrum reveal the intrinsic secondary structure towards β-folding.The peptide-based nanomaterials showed good cytocompatibility in experiments on cell proliferation curves,cell activity,and cell viability assays.The successful use of the designed peptide-based materials for three-dimensional cell culture,encapsulating cells to obtain cell spheres,is expected to be a suitable model for hepatocytes.Using Hep G2 cells in conjunction with muscle satellite cells,it was verified that the designed peptide enabled long-range cell culture for 7-14 days and that the cultured cells maintained good proliferative activity as observed by confocal laser scanning electron microscopy.The interaction between the peptide-based nanomaterials and the cells was investigated,and the effect of peptide concentration on the viscoelasticity and dynamic behaviour of the hydrogel was verified by rheological experiments.Combined with the morphological differences of the cell spheres,increasing the peptide concentration was beneficial to obtain larger and more active cell spheres within a certain range.The cells cultured with the material not only had a high survival rate but also exhibited a differentiation phenotype consistent with that of hepatocytes.The stimulus-responsive peptides based on self-assembled peptides discussed in this thesis have good potential for application in the biomedical field,especially in three-dimensional cell culture and tissue repair. |
