Annegarn Marco, Dirksen Maxim, Hellweg Thomas
Department of Physical and Biophysical Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
Polymers (Basel). 2021 Mar 8;13(5):827. doi: 10.3390/polym13050827.
While cationic microgels are potentially useful for the transfection or transformation of cells, their synthesis has certain drawbacks regarding size, polydispersity, yield, and incorporation of the cationic comonomers. In this work, a range of poly(-isopropylacrylamide) (PNIPAM) microgels with different amounts of the primary amine -(3-aminopropyl)methacrylamide hydrochloride (APMH) as the cationic comonomer were synthesized. Moreover, the pH-value during reaction was varied for the synthesis of microgels with 10 mol% APMH-feed. The microgels were analyzed by means of their size, thermoresponsive swelling behavior, synthesis yield, polydispersity and APMH-incorporation. The copolymerization of APMH leads to a strong decrease in size and yield of the microgels, while less than one third of the nominal APMH monomer feed is incorporated into the microgels. With an increase of the reaction pH up to 9.5, the negative effects of APMH copolymerization were significantly reduced. Above this pH, synthesis was not feasible due to aggregation. The results show that the reaction pH has a strong influence on the synthesis of pH-responsive cationic microgels and therefore it can be used to tailor the microgel properties.
虽然阳离子微凝胶在细胞转染或转化方面可能具有潜在用途，但其合成在尺寸、多分散性、产率以及阳离子共聚单体的掺入方面存在一定缺陷。在这项工作中，合成了一系列含有不同量的伯胺 -（3 - 氨丙基）甲基丙烯酰胺盐酸盐（APMH）作为阳离子共聚单体的聚（N - 异丙基丙烯酰胺）（PNIPAM）微凝胶。此外，在合成含10 mol% APMH进料的微凝胶时，改变了反应过程中的pH值。通过微凝胶的尺寸、热响应溶胀行为、合成产率、多分散性和APMH掺入量对其进行了分析。APMH的共聚导致微凝胶的尺寸和产率大幅下降，而名义上的APMH单体进料中只有不到三分之一掺入到微凝胶中。随着反应pH值升高至9.5，APMH共聚的负面影响显著降低。高于此pH值，由于聚集，合成不可行。结果表明，反应pH值对pH响应性阳离子微凝胶的合成有很大影响，因此可用于调整微凝胶的性能。
