pH/温度响应型聚合物PMAA-b-PDMAEMA的合成、性能调控及应用

Synthesis,performance regulation and application of pH/temperature responsive polymer PMAA-b-PDMAEMA

以甲基丙烯酸叔丁酯(tBMA)、甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)为原料,通过原子转移自由基聚合(ATRP)法合成了两亲性嵌段聚合物聚甲基丙烯酸叔丁酯-b-聚甲基丙烯酸N,N-二甲氨基乙酯(PtBMA-b-PDMAEMA),将其进行水解得到功能可调控的pH/温度双重响应性共聚物PMAA-b-PDMAEMA。采用核磁共振波谱(1H NMR)、傅里叶变换红外光谱(FTIR)、紫外可见分光光度计(UV-Vis)、动态光散射(DLS)及荧光分光光度计等对共聚物的结构及性能进行表征和分析,研究共聚物的嵌段比、分子量及溶液pH对响应性能的调控,并初步考察了共聚物的抗肿瘤潜能。研究结果表明,随着PMAA链段长度增加,等电点向酸性偏移,在等电点时溶液透过率降到最低,表现出良好的pH响应性;温度响应性受溶液pH、分子量及嵌段比的影响,pH越接近等电点、分子量越大,低临界溶液温度(LCST)越低;共聚物与模拟肿瘤细胞膜相互作用后,在pH=5.5酸性微环境下膜中内容物的泄漏率接近100%,实现了对模拟肿瘤细胞的靶向破坏作用,展现了该共聚物良好的环境响应性。

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.