| Enzyme-responsive amphiphilic linear-dendritic block copolymers(LDBCs)have broad application prospects in biomedical materials.They can be prepared by the three main synthetic strategies:the“chain-first”strategy,the“dendron-first”strategy,and the coupling strategy.So far,chain-first method is the most used method but amphiphilic LDBCs synthesized by coupling method has been reported only in one literature.In this thesis,three generations of hydrophobic poly(aryl ethers)(Gn-alkynyl)with an alkynyl group at the central end group were firstly synthesized.Poly(N-vinylpyrrolidone)(PNVP)was synthesized by the reversible addition-chain transfer radical polymerization(RAFT)of NVP.Then,the phenylalanyl-lysine(Phe-Lys)dipeptide was linked to the end of PNVP through functional group conversion,and the end group was converted to an azide-terminated PNVP-Phe-Lys-N3.Finally,the amphiphilic linear-dendritic block copolymers PNVP-b-Phe-Lys-Gn(n=1-3)were prepared by copper(I)-catalyzed alkynyl-azide“click”reaction(Cu AAC)coupling.Their structures and molecular weight were characterized by ~1H NMR spectra and GPC.The self-assembly behavior and enzyme response properties of PNVP-b-Phe-Lys-Gn(n=1-3)were studied by ~1H NMR spectra,fluorescence spectroscopy,transmission electron microscopy(TEM)and particle size analyzer.The results showed that PNVP-b-Phe-Lys-Gn(n=1-3)can self-assemble into spherical micelles in aqueous solution.The critical micelle concentration(CMC)decreased with increasing of benzene ring on hydrophobic polyaryl ethers.After adding trypsin,the copolymer micelles disassemble.The disassemble rate of micelles increased with increasing trypsin concentration.Using the hydrophobic anticancer drug paclitaxel(PTX)as a model drug,the drug release behavior of PNVP-b-Phe-Lys-G3 was studied by UV spectrophotometer,particle size analyzer and TEM.The results showed that the drug-loaded micelles of PNVP-b-Phe-Lys-G3could release PTX under the action of trypsin. |
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