Synthesis,performance regulation and application of pH/temperature responsive polymer PMAA-b-PDMAEMA
The amphiphilic block polymer poly(tert-butyl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate)(PtBMA-b-PDMAEMA)was synthesized by atom transfer radical polymerization(ATRP)using tert butyl methacrylate(tBMA)and N,N-dimethylaminoethyl methacrylate(DMAEMA)as raw materials.The functional controllable pH/temperature dual responsive copolymer PMAA-b-PDMAEMA was obtained by hydrolysis.The structure and properties of the copolymer were characterized and analyzed by nuclear magnetic resonance spectroscopy(1H NMR),fourier transform infrared spectroscopy(FTIR),ultraviolet-visible spectrophotometer(UV-Vis),dynamic light scattering(DLS)and fluorescence spectrophotometer.The regulation of the block ratio,molecular weight and solution pH of copolymers on their response performance was studied,and their anti-tumor potential was preliminarily investigated.The results showed that with the increase of the length of PMAA chain segment,the isoelectric point shifted to acid,and the solution transmittance decreased to the lowest at the isoelectric point,showing good pH responsiveness.Temperature responsiveness was influenced by solution pH,molecular weight and block ratio.As the pH value was approached the isoelectric point and the molecular weight increased,a lower critical solution temperature(LCST)was obtained.After the copolymer interacted with simulated tumor cell membrane,the leakage rate of the contents in the membrane was nearly 100%under pH 5.5 acidic microenvironment,achieving the targeted destruction effect on simulated tumor cells,exhibiting the good environmental responsiveness of the copolymer.
atom transfer radical polymerizationpolymersphase changepH/temperature responseadjustability
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