Preparation And Research Of Supramolecular Peptide Materials Based On DOPA

Marine mussels can freely attach to various reefs,ships and other surfaces in the sea without falling off.It is mainly dependent on the strong adhesion ability of its feet.Therefore,scientific workers have developed a keen interest in the composition and mechanism of mussels' foot protein.There are some studies showing that the strong adhesion ability of mussels' foot is related to an important amino acid,L-3,4-dihydroxyphenylalanine(dopa)in mussels' foot protein.Accordingly,the development and application of dopa-related polymer materials and adhesives have rapidly become a hot research direction in biomimetic materials.With the exploration of dopa,the specific mechanism of the adhesion ability of mussels can be identified and facilitates the design of new biomimetic materials and bio adhesives owning high environmental adaptability.The article is divided into four chapters.In the first chapter,it mainly introduces the background knowledge of the problems discussed in the article,including mussel foot protein and L-Dopa and a brief introduction of hydrogels.Then the application and development of dopa in hydrogels based on self-assembled peptides was discussed.Finally,the technology of single molecule force spectroscopy based on the atomic force microscopy was introduced.In the second chapter,we studied the synergetic adhesion of dopa and positive charge.Mussel foot protein contains a lot of lysine residues positively charged besides dopa.There is a synergistic effect between lysine and dopa.However the exact mechanism of this effect remains unexplored,so we designed some experiments to explore it.First,two dipeptides were synthesized,which are lysine-dopa and dopa-lysine.The amino group in the side chain of lysine is first protected as a control.The dipeptides were flanked to the AFM cantilever tip.The interaction strength between these dipeptides and mica or titanium dioxide substrate was tested using single molecule force spectroscopy.The result indicates that there is a synergistic effect between the positively charged of lysine and dopa.Moreover,the synergistic effect is related to the distinct structure for load distribution within the molecules.The results explain the synergetic effect between the positive charge and dopa,and provide some new inspirations for the design of new artificial supramolecular materials.In the third chapter,we reported a new kind of supramolecular hydrogel based on polypeptides modified with dopa.The hydrogel exhibits strong interaction with cells as indicated by single molecule force spectroscopy experiments,leading to the excellent adhesion properties of cells.Moreover,cell catch and release experiments has been performed by changing pH to demonstrate the application of such kind of hydrogels as a prince of principle.Owing to the amazing cell adhesion ability as well as the outstanding biocompatibility,we hope that such kind of hydrogels may find broad applications in the field of biomedical engineering and responsive soft materials.At the end,we made a summary of all the whole work and discussed the future development and applications of this field.