Molecular assemblies that transform in response to pH and saccharide concentration are promising nanomaterials in the field of biomedicine, and polymeric micelles of amphiphilic polymers with phenylboronic acids (PBAs) have been studied. Herein, we report the impact of zwitterions on the acidity constant for the collapse and the glucose sensitivity of a polymeric micelle produced from a diblock copolymer comprising polyacrylamides with PBA and zwitterionic carboxybetaine (PAEBB-b-PCBAAm). The diblock copolymer was synthesized through reversible addition–fragmentation chain-transfer polymerization followed by deprotection. PAEBB-b-PCBAAm produced micellar aggregates in aqueous solutions at a neutral pH, and the polymeric micelles collapsed at a pH of 11.0 because the PBA transformed into a hydroxyboronate anion. The pK_a decreased in the presence of glucose owing to boronate ester formation. The PCBAAm chain significantly increased the pH at which the molecular assemblies dissociated. This is probably because the pK_a of boronic acid increased through the dipolar interaction of zwitterions, and/or the zwitterionic polymer corona is valid for screening of PBA ionization and electrostatic repulsion of boronate anions. This study on the modulation of pK_a through the zwitterionic interaction can facilitate the molecular design of pH- and saccharide-responsive biomaterials.

中文翻译：

---

两性离子对苯硼酸嵌段共聚物酸度常数和葡萄糖敏感性的影响

响应 pH 值和糖浓度而发生转变的分子组装体是生物医学领域有前途的纳米材料，并且已经研究了两亲性聚合物与苯基硼酸 (PBA) 的聚合胶束。在此，我们报告了两性离子对由包含聚丙烯酰胺、PBA 和两性离子羧基甜菜碱 (PAEBB- b -PCBAAm)的二嵌段共聚物产生的聚合物胶束的崩解酸度常数和葡萄糖敏感性的影响。二嵌段共聚物是通过可逆加成断裂链转移聚合然后脱保护合成的。 PAEBB- b -PCBAAm 在中性 pH 值的水溶液中产生胶束聚集体，并且由于 PBA 转化为羟基硼酸根阴离子，聚合物胶束在 pH 值为 11.0 时崩溃。在葡萄糖存在下，由于硼酸酯的形成，pKa降低_。 PCBAAm 链显着提高了分子组装体解离的 pH 值。这可能是因为硼酸的pKa_通过两性离子的偶极相互作用而增加，和/或两性离子聚合物电晕对于筛选PBA电离和硼酸盐阴离子的静电排斥是有效的。这项通过两性离子相互作用调节 pKa 的研究可以_促进pH 和糖响应生物材料的分子设计。