Department of Chemical Engineering, University of Mississippi, Oxford, MS, 38677, USA.
Department of Biomedical Engineering, University of Mississippi, Oxford, MS, 38677, USA.
Macromol Rapid Commun. 2022 Dec;43(24):e2200420. doi: 10.1002/marc.202200420. Epub 2022 Jul 24.
Poly 2-vinyl-4,4-dimethylazlactone (PVDMA) has received much attention as a "reactive platform" to prepare charge-shifting polycations via post-polymerization modification with tertiary amines that possess primary amine or hydroxyl reactive handles. Upon hydrolysis of the resulting amide or ester linkages, the polymers can undergo a gradual transition in net charge from cationic to anionic. Herein, a systematic investigation of the hydrolysis rate of PVDMA-derived charge-shifting polymers is described. PVDMA is modified with tertiary amines bearing either primary amine, hydroxyl, or thiol reactive handles. The resulting polymers possess tertiary amine side chains connected to the backbone via amide, ester, or thioester linkages. The hydrolysis rates of each PVDMA derivative are monitored at 25 and 50 °C at pH values of 5.5, 7.5, and 8.5, respectively. While the hydrolysis rate of the amide-functionalized PVDMA is negligible over the period investigated, the hydrolysis rates of the ester- and thioester-functionalized PVDMA increase with increasing temperature and pH. Interestingly, the hydrolysis rate of the thioester-functionalized PVDMA appears to be more rapid than the ester-functionalized PVDMA at all pH values and temperatures investigated. It is believed that these results can be utilized to inform the future preparation of PVDMA-based charge-shifting polymers for biomedical applications.
聚 2-乙烯基-4,4-二甲基氮杂环丁酮（PVDMA）作为一种“反应性平台”，通过与具有伯胺或羟基反应性官能团的叔胺进行聚合后修饰，已引起了广泛关注，可制备出电荷转移聚阳离子。酰胺或酯键的水解会导致聚合物的净电荷从阳离子逐渐转变为阴离子。本文对 PVDMA 衍生的电荷转移聚合物的水解速率进行了系统研究。用带有伯胺、羟基或巯基反应性官能团的叔胺对 PVDMA 进行修饰，得到的聚合物具有通过酰胺、酯或硫酯键连接到主链上的叔胺侧链。分别在 25°C 和 50°C、pH 值为 5.5、7.5 和 8.5 下监测每种 PVDMA 衍生物的水解速率。在研究期间，酰胺官能化 PVDMA 的水解速率可以忽略不计，而酯和硫酯官能化 PVDMA 的水解速率随温度和 pH 值的升高而增加。有趣的是，在所有研究的 pH 值和温度下，硫酯官能化 PVDMA 的水解速率似乎都比酯官能化 PVDMA 快。相信这些结果可用于为生物医学应用制备基于 PVDMA 的电荷转移聚合物提供信息。
