Precise Wool Keratin Patterns:From Design To Applications

In recent years,the use of micro-nano manufacturing processes to highly precise patterns of proteins or peptides has provided important applications in cell biology,tissue engineering,pharmaceutical science,and optoelectronics.On the other hand,as a natural biological prote:in with large reserves,wool keratin(WK)has excellent water solubility,good biocompatibility and controlled degradation.However,WK itself usually cannot self-assemble to form a gel network or other insoluble form during processing,which limits its practical application.In this thesis,for the first time,we present the use of WK as a structural biomaterial for fabricating precise protein microarchitectures.To obtain photosensitivity,the WK can be prepared by simple biochemical modification,without significantly changing its structure and function.The main research contents and results of this thesis are as follows:1.Photocrosslinkable WK was extracted from wool fibres,and its side groups were reacted with the photoreactive reagent 2-isocyanatoethyl methacrylate(IEM),yielding a photoactive WK precursor.Under light irradiation,the intermolecular chemical crosslinking between WK molecules could be successfully initiated by commercially available photoinitiators.It was worth noting that the entire lithography process did not require the use of toxic solvents,expensive developers,complex lithographic steps,strict operation conditions,or expensive equipment.Through photolithography,we efficiently prepared protein microstructures of various patterns and obtained protein micropatterns with an accuracy of 2?m.2.Using photoactive WK as a photoresist,the WK film with surface patterned microstructure was prepared by soft lithography.The experimental results showed that the patterns on the WK film maintained good integrity after two transfer steps.We also used proteases to verify the stability and degradability of crosslinked WK films,and at the same time demonstrated the hydrophilicity of crosslinked WK films.In addition,the formation of structural colors caused by periodically arranged microstructures on the WK film was observed.3.The application prospects of as-prepared protein patterned microstructures were explored.To demonstrate that the patterned keratin micro structure could be used as a bio-friendly cell substrate,without the addition of any cell-adhesive ligands,these hydrophilic micropatterned protein structures were tested as patterned substrates for the spatial guidance of cells.And WK structures in complex patterns that display typical iridescent behaviour were formed over macroscale areas(cm).Furthermore,by simply mixing with nanoparticles,enzymes and other dopants,various'functional WK resists'could be generated.We expect that the development of WK microstructures can be further applied in tissue engineering,soft photonics,sensing,and drug delivery.