Synthesis And Assembly Of Thermosensitive Collagen Mimetic Peptides

Through molecular design,chiral amplification of supramolecular assembly and intelligent control of chirality and optical properties are realized.It has not only important academic value,but also important application prospects in the field of developing new chiral materials.Collagen mimetic peptides(CMPs)are the kind of polypeptides which mimics the amino acid sequence structure of collagen peptides.It has broad application prospects in the field of biomedical materials;oligo(ethylene glycol)s(OEGs)are thermos-sensitive moieties.It can solubilize the whole molecule below the phase transition temperature.Above the phase transition temperature,it can also form hydrophobic microenvironment and shield the internal groups effectively.As a strong hydrophobic group,tetraphenylethylene not only brings hydrophobicity to the whole molecule,but also its derivatives usually have the aggregation-induced luminescence(AIE)characteristics,which has broad application prospects in the field of optoelectronic materials.In this paper,a kind of thermos-sensitive collagen mimetic peptides which combine CMPs,Intelligent responsiveness and AIE characteristics was prepared by molecular design.Its thermos-responsive behaviors,chiral conformation,supramolecular amphiphilic self-assembly behaviors and fluorescence properties were researched.The main work includes the following aspects:1.A serial of amphiphilic collagen mimetic peptide were successfully prepared by using effective synthetic strategies.The OEGs moieties and tetraphenylvinyl moieties were modified at the amino end and carboxyl end respectively by the efficient amidation of pentafluorophenol active esters.Their structures were characterized by ~1H NMR.2.The thermos-sensitive properties of OEGylated amphiphilic collagen mimic peptides were studied.The phase transition temperatures of these thermos-sensitive amphiphilic polypeptides were measured by UV/vis spectroscopy.The effects of end-capping groups and concentration on the phase transition temperature were discussed.The reversibility and repeatability of the phase transition behavior were further discussed.3.Supramolecular chirality self-assembly and chirality properties of OEGylated amphiphilic collagen mimic peptide were studied.Firstly,the influence of the proportion of bad solvents in mixed solvents on supramolecular chiral amplification and transfer was discussed.The control of temperature on chiral changes of supramolecular assemblies is discussed.Then the self-assembled morphology was studied by atomic force microscopy.4.The fluorescence properties of the OEGylated amphiphilic collagen mimic peptide were studied by introducing tetraphenylvinyl units.Firstly,the aggregation-induced luminescence characteristics of these polypeptides were investigated,and the effect of temperature-sensitive aggregation on their fluorescence characteristics was further explored.In a word,through thesis work,we successfully prepared a class of amphiphilic polypeptides which integrates collagen peptide,temperature-sensitive dendronization and aggregated luminescence,and their supramolecular chiral assembly was studied in depth,so as to enhance the chirality of supramolecular chiral assembly and realize the intelligent luminescence characteristics and reversible control of chirality of supramolecular chiral assembly.