Constructing Drug Carrier Based On Enzyme-response Peptide Containing Raft Agent

Enzyme-responsive peptides are a class of peptides that can be recognized by specific types of enzymes and be hydrolyzed,thus having a wide range of biomedical prospects.Cathepsin B is a type of enzyme that exists in lysosomes.It is widely involved in all aspects of cell life activities and is overexpressed in cancer cells.Therefore,peptide synthesizer is used to synthesize a peptide sequence(glycine-leucine-phenylalanine-glycine)that can be specifically recognized by Cathepsin B.RAFT agent is used to conjugate the peptide and the anticancer drug paclitaxel for drug release.The successful synthesis was confirmed by nuclear magnetic(NMR),mass spectrometry(MS),high performance liquid chromatography(HPLC).2-(2-methoxyethoxy)ethyl methacrylate(MEO2MA)and oligo(ethylene glycol)methyl ether methacrylate(OEGMA)were used to polymerize temperature responsive random copolymer with the RAFT conjugate.The copolymer was characterized by nuclear magnetic resonance(NMR)and gel permeation chromatography(GPC).The lower critical solution temperature(LCST)was tested by UV spectroscopy to study the effects of monomer ratios,end group changes,and buffer usage on LCST.The enzyme responsive drug release were studied by MS and HPLC.Then,star polymer was synthesized and characterized as linear polymer.The relationship between it and linear polymer was discussed.It can be confirmed by the research that various factors affect the solubility of polymers by affecting the formation of hydrogen bonds between polymer and water.And these factors have a greater impact on the temperature sensitivity of star polymer.Through the study of enzyme-responsive drug release,it can be confirmed that the drug molecule can be successfully released from the polymer and has a high release efficiency.This drug carrier has good biomedical prospects.