Well-defined polymer–protein bioconjugates are widely used in therapeutics and biocatalysis. One of the challenges in the synthesis of bioconjugates is the efficient separation of the target conjugate molecules from reaction systems. In this research, surface coassembly of polymer brushes and polymer–protein bioconjugates is investigated, and it is demonstrated that the coassembly approach can be applied in the purification of polymer–protein bioconjugates. Bovine serum albumin-poly(N-isopropylacrylamide) (BSA-PNIPAM) bioconjugates were synthesized by the “grafting from” approach, and PNIPAM brushes on silica particles were prepared by the “grafting to” approach. PNIPAM brushes on silica particles are able to coassemble with BSA-PNIPAM at a temperature above the lower critical solution temperature of PNIPAM. Two-layer surface structures with collapsed PNIPAM in the inner layers and BSA in the outer layers are formed on the silica particles. The size of the silica particles and molecular weight of PNIPAM on the bioconjugates exert influences on the coassembly. The coassembly approach can be used in the purification of bioconjugates. After repeated coassembly centrifugation-release cycles, all the BSA-PNIPAM bioconjugates can be removed from the reaction solutions, and the purified bioconjugates are obtained.

中文翻译：

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聚合物刷和聚合物-蛋白质生物共轭物的表面共组装：在温和条件下纯化生物共轭物的有效方法

定义明确的聚合物-蛋白质生物共轭物广泛用于治疗和生物催化。生物缀合物合成中的挑战之一是从反应系统中有效分离靶缀合物分子。在这项研究中，研究了聚合物刷和聚合物-蛋白质生物共轭物的表面共组装，并证明了该组装方法可用于聚合物-蛋白质生物共轭物的纯化。牛血清白蛋白-聚（Ñ-“异丙基丙烯酰胺”（BSA-PNIPAM）生物共轭物通过“嫁接自”方法合成，而二氧化硅颗粒上的PNIPAM刷则通过“嫁接至”方法制备。二氧化硅颗粒上的PNIPAM刷能够在比PNIPAM的下临界溶液温度高的温度下与BSA-PNIPAM共组装。在二氧化硅颗粒上形成内层具有PNIPAM塌陷，外层具有BSA塌陷的两层表面结构。二氧化硅颗粒的大小和生物共轭物上PNIPAM的分子量对共组装产生影响。共组装方法可用于生物缀合物的纯化。在重复的共组装离心-释放循环之后，可以从反应溶液中除去所有的BSA-PNIPAM生物缀合物，并且获得了纯化的生物缀合物。