| Redox responsive amphiphilic block copolymer can self-assemble into micelles in aqueous phase,which can be used as drug delivery.Under the condition of corresponding stimulation or environmental changes,it will give response and help control drug release.The stimuli include external and intrinsic factors of the organism,such as temperature,pH,glutathione?GSH?and other factors.Among them,the concentrations of glutathione in cancer cells and normal cells have quantitative differences.According to this characteristic,block copolymer linked by molecular units of disulfide-bond can be used as anticancer drug delivery,to achieve the purpose of drug control release.Multi-block copolymer is one kind of block copolymer,which contains more than two different types of polymer block.Because of more chemical properties and types of polymer block,in the design of functional diversity,it has more potential than diblock and triblock copolymer in response drug release system.In this paper,a novel of amphiphilic multi-block copolymers linked by molecular units of disulfide-bond which had redox-response was synthesized,in which the hydrophilic block was PEG,and the hydrophobic block was PLA.The amphiphilic multi-block copolymers can self-assemble into spherical micelles in aqueous media with size from 100 nm to 160 nm?blank micelles?and 120 nm to 180 nm?drug-loaded micelles?,CMC from0.06 to 0.08 mg.mL-1,and DLC from 4.08%to 5.61%with different molecular weight of PEG and PLA respectively.Further evaluation confirmed that the copolymer micelles kept stable up to 26 days with the physiological condition Fluorescence microscopy measurements and MTT assay demonstrated that the micelles exhibited a faster drug release and higher cellular proliferation inhibition due to the effect of intracellular reduction-responsive GSH-mediated.These results suggested the micelles would provide a favorable platform to construct excellent drug delivery systems for cancer therapy. |
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