Construction And Anticancer Properties Of Peptide-gold Nanoparticles And Peptide Hydrogel System

As a kind of excellent gene/drug carrier,peptide has many advantages such as diverse biological activity,low immunogenicity,good biocompatibility and controllable self-assembly performance,and is widely used in gene/drug delivery systems.At the same time,some special structural peptide fragments extracted from organisms can also be used as therapeutic molecules,and are gradually applied in the fields of anticancer and antibacterial.The peptides can be used as a gene or drug carrier,or modified on other carriers,loaded with drugs or gene-forming nanoassemblies,can promote the internalization of drugs or genes,control the fixed release of drugs in tumor tissues,and improve gene transfection.Efficiency,enhance the therapeutic effect of the drug.In recent years,studies on the delivery of drugs and genes mediated by peptides modification and their research in the fields of anticancer and antibacterial have attracted the attention of experts and scholars.Based on the different advantages of peptides,this paper studied the potential of novel peptides in the transmission of anticancer drugs and their potential as therapeutic molecules in the fields of anticancer and antibacterial.In the first part,peptide chains required for the experiment were prepared,purified and detected.Seven peptides:antibacterial peptides FIGAIARLLSKIF?Kn2?,FIKRIARLLRKIF?Kn2-7?,CKn2,CKn2-7,CKn2-RGDS?AP1?,CKn2-7-RGDS?AP2?,fully protected peptide Nap-FFY?t-Bu?E?OtBu?-OH,were synthesized in a 2-chloro-trityl chloride resin solid phase reactor using Standard Fmoc Solid phase peptide synthesis?SPPS?technology.The synthesized peptide chains were characterized by Bruker 400MHz NMR and LCQ Advantage electrospray mass spectrometry.The actual NLS molecular weight is consistent with the calculated theoretical value by the double charge peak calculation.The purity of each peptide chain was determined by high performance liquid chromatography?HPLC?.In the second part,based on the antibacterial peptide BmKn2 and its mutant BmKn2-7,one cysteine was added at the N-terminus of the peptide,and using the Au-S coordination bond to construct the peptide-modified nanogold particles?AuNP@Kn2?And AuNP@Kn2-7).Kn2,Kn2-7,CKn2,CKn2-7,CKn2-RGDS?AP1?,and CKn2-7-RGDS?AP2?were designed and synthesized.The sodium citrate reduction method was used to reduce chloroauric acid into gold nanoparticles with particle size of about 18 nm in a controlled state.The gold nanoparticles was modified from the toxin-derived peptide BmKn2-7,and the toxicity was further studied.We successfully prepared the gold nanoparticles carrier?AuNP@Kn2-7?modified by the peptide Kn2-7 with a particle size of 34.07 nm.Compared with the peptide carrier Kn2-7,it has low cytotoxicity;in addition,we successfully prepared Kn2-7-RGDS modified nanogold carrier?AuNP@Kn2-7-RGDS?with a particle size of 96.05 nm.It was found that the Kn2-7-RGDS modified nanogold carrier?AuNP@Kn2-7-RGDS?has a certain tumor cell inhibition effect.In the third part,the anti-tumor 6-MP prodrug containing the polypeptide Nap-FFYE-CO-NH-?CH₂?₂-SS-MP was prepared.Due to the excellent self-assembly property of the polypeptide fragment Nap-FFYE-OH,the 6-MP prodrug Nap-FFYE-CO-NH-?CH₂?₂-SS-MP can be observed by transmission electron microscopy?TEM?.Self-assembly occurs in a neutral aqueous solution to form nanofibers having a diameter of about 50 nm.In vitro drug release experiments showed that 6-MP in the 6-MP prodrug did not show any release in the absence of glutathione?GSH?,but under simulated tumor environment conditions,the GSH concentration was controlled.At 40mM,the disulfide bond was broken,and the in vitro release curve showed significant GSH sensitivity.The cumulative drug release efficiency after 24 h almost reached 75%.At the same time,the results of in vitro cytotoxicity experiments also showed that 6-MP prodrugs have lower cytotoxicity than free 6-MP.Therefore,this disulfide-containing reduction-sensitive 6-MP prodrug is expected to improve the stability of the anticancer drug 6-mercaptopurine,poor cytotoxicity,and further achieve responsive drug release at the tumor site.The anti-tumor drug 6-mercaptopurine is enriched in tumor cells,and thus has certain application potential in the clinical treatment of cancer.