Synthesis And Application Of Peptide-conjugated Fluorescent Probe With Aggregation-induce Emission Characteristics In Cancer Diagnosis And Treatmet

Early diagnosis and timely treatment of cancer are all crucial to cure cancer.Up to now,although more and more technologies are widely used in the diagnosis and treatment of cancer.It is still a great challenge for us to cure cancer completely.The combination of diagnosis and treatment of cancer is not only beneficial to the accurate treatment and complete cure of cancer,but also beneficial to the systematic,comprehensive and in-depth understand the nature of cancer about its occurrence and development.Therefore,it will point a new direction for cancer research,and provide a new opportunity to cure cancer if we could establish a multi-functional and smart system about cancer theranostics.In this thesis,several peptide-conjugated fluorescent probes with aggregation-induced emission(AIE)characteristics have been developed for cancer theranostics.Through the study on the rational design and efficient synthesis of multi-functional probes,we explored their application in drug release tracking,long time cell imaging and cancer theranostics,which would provide new methods and new ideas for theranostics of clinical disease.This thesis mainly includes the following sections:(1)With the help of thiol-maleimide "click" reaction and azide-alkyne "click"reaction to form chemical coupling between the functionalized cell penetrating peptides FCPPs(CRRRRRRRRRPLGLAGPra-NH2),the therapeutic unit DOX and the AIE probe PyTPE,an efficient cell-permeable and protease-responsive probe(DFP)with aggregation induced emission characteristics had been successfully synthesized.DFP could be selectively cleaved by a cancer-related enzyme matrix metalloproteinase-2(MMP-2).Without MMP-2,DFP could not go inside the cells easily.In the presence of MMP-2,PyTPE can be cleaved from DFP which would self-aggregate because of the hydrophobic interaction and turn on its yellow fluorescence,and the cell penetrating peptides(CPPs)linked DOX could easily interact with cell membrane and then go inside the cell.The appearance of the yellow fluorescence indicates the release of the therapeutic unit to the cells.The selective delivery of the drug to the MMP-2 positive cells was also confirmed by using the intrinsic red fluorescence of DOX.Our result suggests a new and promising method for the controlled drug delivery,real-time tracking of drug release and distinguishing different cell lines in MMP-2 overexpression cells.(2)With the help of azide-alkyne "click" reaction to form chemical coupling between the integrin αvβ3-targeted multi-functionalized peptides TNC(DGRKRRRRRRRRPra-NH2)and the AIE probe PyTPE,a integrin αvβ3-targeted and nucleus-specific fluorescent probe(TNCP)with aggregation-induced emission characteristics have been successfully synthesized.TNCP could specifically recognize the cancer-related integrin αvβ3 and importin.It could easily interact with cell membrane to enter cells with good AIE fluorescence imaging effect.TNCP and siRNA can be assembled by electrostatic and hydrophobic interaction with efficient encapsulation to target transport to the site of the tumor for gene therapy.The AIE probe was used to track the gene transport process in order to provide a new method and strategy for further revealing the mystery of gene therapy in cancer theranostics.(3)With the help of azide-alkyne "click" reaction to form chemical coupling between the integrin αvβ3&aminopeptidase N(CD13)dual-targeted multi-functionalized peptides TCNT(CNGRCRRRRGPraGRRRRKRGD-NH2)and the AIE probe PyTPE,a integrin αvβ3&CD13 dual-targeted and nucleus-specific fluorescent probe(TCNTP)with aggregation-induced emission characteristics have been successfully synthesized.TCNTP could specifically recognize the cancer-related integrin integrin αvβ3,CD 13 and importin.It could easily interact with cell membrane to get into cells for efficient nucleus-specific imaging,long-term and low-toxicity tracing of cancer cells.TCNTP exhibited strong fluorescence in nucleus of the integrin αvβ3 and CD 13 overexpression cells due to the specific-targeting ability,efficient transport capacity and aggregation induced emission characteristic in more crowded space.Furthermore,TCNTP could be used as a new type of carrier for anticancer drugs,which makes it possible for highly effective anticancer drugs delivery in cancer theranostics.(4)With the help of azide-alkyne "click" reaction to form chemical coupling between the tyrosine(Tyr)derivative and the AIE probe TPE-N3,a peroxidase and H2O2 dual-responsive peptide-conjugated fluorescent probe(TT)with aggregation-induced emission characteristics have been successfully synthesized.TT had good biocompatibility and could be used for the specific detection of horseradish peroxidase(HRP)and H2O2-After entering cancer cells,TT could form hydrophobic polymers through self-polymerization under the co-catalysis of peroxidase and H2O2.It could turn on its fluorescence for cell imaging and self-assemble to kill cells.It extends the scope of application of AIE molecules in cancer diagnosis and treatment,and initiates a new field of AIE molecules used for cancer theranostics.