Design Of Polyethylene Glycol Modified Phenylalanine Dipeptide Self-assembled Nanocarriers And Its Application In Antitumor By Delivering Of SiRNA

RNA interference?RNAi?is a biological process that uses a highly conserved double-stranded RNA molecule to specifically bind to a homologous mRNA molecule to inhibit the expression or translation of the target gene.As a technology that can specifically silence or excise the expression of specific genes,RNA interference has been widely used in the exploration of gene function and the research of malignant tumor therapy.Due to the complex physiological and biochemical environment of the human body,how to ensure the accurate,stable,and efficient delivery of functional short RNA molecules to the target tissue cells is one of the key issues to be solved at present.Therefore,seeking an effective gene delivery method is the primary task of achieving RNA interference and achieving gene therapy.As a cationic short peptide,phenylalanine dipeptide molecule?Phe-Phe?has excellent biocompatibility,structural diversity,and easy functionalization.In recent studies,phenylalanine dipeptide self-assembled molecules have been widely used as carrier delivery functional nucleotides such as siRNA,microRNA,and long-chain non-coding RNA?lncRNA?,etc.,for the purpose of gene therapy.However,through extensive and in-depth studies,the poor solubility of water and low serum stability of phenylalanine dipeptide self-assembled molecules have increasingly exposed their further in vivo studies.In this paper,we focused on the modification of phenylalanine dipeptide self-assembled nanocarriers.We chose polyethylene glycol to modify the phenylalanine dipeptide.On the one hand,polyethylene glycol can effectively increase phenylalanine dipeptides.The water solubility,on the other hand,the shell-like structure formed on the surface of the phenylalanine dipeptide self-assembly carrier enhances the stability of the carrier in the serum,and prevents the carrier from binding to serum albumin and thus degrades.In addition,arginine has been added to the molecular structure to increase the positive charge of self-assembled nanocarriers.Survivin is over-expressed in tumor cells,and the protein produced by its translation can block the process of apoptosis.Therefore,the nano-spheroidal carrier mPEG₆-RAFF formed by self-assembly of PEGylated phenylalanine dipeptides is used.?Oligohexamethyleneglycol-arginine-alanine-phenylalanine-phenylalanine?si RNA targeting survivin was used to model the MCF-7 cell line through a series of experimental procedures.Gene Delivery Ability and Gene Interference Effect of Glycol Modified Phenylalanine Dipeptide Nanocarriers.In addition to the modification of polyethylene glycol groups,phenylalanine dipeptide molecules also increase arginine to increase the positive charge of phenylalanine dipeptide molecules.It was found that the mPEG₆-RAFF self-assembled at the concentration of 1mg/mL can form a clear and stable nano-spheroidal structure.At this concentration,the mPEG₆-RAFF nano-carrier has a very low cytotoxicity,and at the same time,the nano-carrier.It can be combined with siRNA to a maximum extent at N/P of 100 to form a stable composite structure.Serum stability experiments showed that the siRNA was not completely degraded after 48 h incubation in the presence of 50%serum.Confocal laser scanning microscopy revealed that the mPEG₆-RAFF nanocarriers can effectively transfect TAMRA-tagged si RNAs into cells.After that,the cells transfected with siRNA against survivin were detected by flow cytometry.The phenomenon of obvious apoptosis,real-time quantitative fluorescence PCR technology further proved the cause of this phenomenon,the use of mPEG6-RAFF si RNA transfected MCF-7 cells in survivin expression decreased significantly.Therefore,thePEG-modifiedphenylalaninedipeptideself-assembled nanocarriers studied in this paper have excellent properties and have achieved good results in a series of experimental studies.It can be used as a novel and effective vector for gene therapy.Deeper research in the field provides the basis.