Temperature-Swing Adsorption of Proteins in Water Using Cationic Copolymer-Grafted Silica Particles
Temperature-Swing Adsorption of Proteins in Water Using Cationic Copolymer-Grafted Silica Particles
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DOI：
10.1021/ie200779w
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发表时间：
2011-11-16
影响因子：
4.2
通讯作者：
Nakano, Yoshio
中科院分区：
文献类型：
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作者：
Morisada, Shintaro;Namazuda, Ken-ichiro;Nakano, Yoshio
以聚（N-异丙基丙烯酰胺）（PNIPA）为接枝物，以乙烯基苄基三甲基氯化铵（VBTA）、甲基丙烯酸二甲氨基乙酯（DMAEMA）或N，N-二甲基丙烯酰胺（DMAA）为共聚单体，制备了硅胶颗粒吸附剂，并对牛血清白蛋白（BSA）进行了变温吸附实验。PNIPA接枝和P（NIPA-co-DMAA）接枝的SiO2粒子在298和313 K下在水中的表面电位均为负值，而P（NIPA-co-VBTA）接枝的SiO2粒子在298和313 K下的表面电位均为正值，这是因为VBTA是一种季铵盐，在水溶液中带正电荷。对于P（NIPA-co-DMAEMA）接枝的SiO2粒子，随着温度从298 K升高到313 K，其表面电位从正变为近零。这可能是因为接枝共聚物的线团到小球的转变导致DMAEMA基团的脱水和去质子化，DMAEMA基团是叔胺并且只能在水相中带正电荷。虽然PNIPA接枝和P（NIPA-co-DMAA）接枝的二氧化硅颗粒不能吸附BSA，但P（NIPA-co-VBTA）接枝和P（NIPA-co-DMAEMA）接枝的二氧化硅颗粒吸附BSA，表明BSA是通过带负电荷的BSA和带正电荷的共聚物之间的静电吸引吸附在二氧化硅表面上的。此外，P（NIPA-co-VBTA）接枝和P（NIPA-co-DMAEMA）接枝的二氧化硅粒子通过变温操作在298 K重复吸附BSA并在313 K脱附部分预吸附的BSA。这种BSA解吸可能是由于接枝共聚物的线团到球的转变增加温度而导致BSA可接近的带正电荷的基团的数量减少。
We have prepared silica particles grafted with-poly(N-isopropylacrylamide) (PNIPA) copolymers as adsorbent for the temperature swing adsorption of bovine serum albumin (BSA), in Water, where vinylbenzyl trimethylammonium chloride (VBTA); 2-(dimethylamino)ethyl methacrylate (DMAEMA), or N,N-dimethylacrylamide (DMAA) was employed as a comonomer. The surface potentials of PNIPA-grafted and P(NIPA-co-DMAA)-grafted silica particles in water at 298 and 313 K were negative, while those of P(NIPA-co-VBTA)-grafted silica particle were positive, because VBTA is a quaternary ammonium salt and positively charged in aqueous solutions. As for the P(NIPA-co-DMAEMA)-grafted silica particle, the surface potential changed from positive to near zero with increasing temperature from 298 K to 313 K. This may be because the coil-to-globule transition of grafted copolymers leads to the dehydration and deprotonation of DMAEMA group, which is a tertiary amine and can be positively charged only in the aqueous phase. Although PNIPA-grafted and P(NIPA-co-DMAA)grafted silica particles failed to adsorb BSA, P(NIPA-co-VBTA)-grafted and P(NIPA-co-DMAEMA)-grafted silica particles adsorbed BSA, indicating that BSA, is adsorbed by the electrostatic attraction between the negatively charged BSA and the positively charged copolymers on the silica surface. Moreover, P(NIPA-co-VBTA)-grafted and P(NIPA-co-DMAEMA)-grafted silica particles repeatedly adsorbed BSA at 298K and desorbed some of the preadsorbed BSA at 313 K via the temperature swing Operation. This BSA desorption may result from the decrease in the number of the positively charged groups accessible to BSA due the Coil-to-globule transition of the grafted copolymers increasing temperature.