Anionic poly(vinylcaprolactam-co-itaconicacid-co-dimethylitaconate) microgels were synthesized via dispersion polymerization and their responsiveness towards cations, namely Mg²⁺, Sr²⁺, Cu²⁺ and Fe³⁺, was investigated. The itaconic moieties chelate the metal ions which act as a crosslinker and decrease the electrostatic repulsion within the network, leading to a decrease in the gel size. The responsiveness towards the metal ion concentration has been studied via dynamic light scattering (DLS) and the number of ions bonded within the network has been quantified with ion chromatography. Through the protonation of the carboxylate groups in the gel network, their interaction with the cations is significantly lowered, and the metals are consequently released back in solution. The number of ions released was assessed also via ion chromatography for all four ions, whilst Mg²⁺ was also used as a model ion to display the reversibility of the system. The microgels can bond and release divalent cations over multiple cycles without undergoing any loss of functionality. Moreover, these gels also selectively entrap Fe³⁺ with respect to the remaining divalent cations, opening the possibility of using the proposed gels in the digestive tract as biocompatible chelating agents to fight iron overaccumulation.

中文翻译：

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金属阳离子响应性阴离子微凝胶：对生物学相关的二价和三价离子的行为

通过分散聚合合成了阴离子型聚己内酰胺-共-衣康酸-共-二甲基衣康酸酯阴离子微凝胶，研究了它们对阳离子Mg 2 ⁺，Sr 2 ⁺，Cu ²⁺和Fe ³⁺的响应性。衣康酸部分螯合充当交联剂的金属离子，并降低网络内的静电排斥力，从而导致凝胶尺寸减小。通过以下方法研究了对金属离子浓度的响应性动态光散射（DLS）和网络中键合的离子数已通过离子色谱法进行了定量。通过凝胶网络中羧酸根基团的质子化，它们与阳离子的相互作用显着降低，因此金属在溶液中释放回去。还通过离子色谱法评估了所有四个离子的释放离子数，同时还使用Mg ²⁺作为模型离子来显示系统的可逆性。微凝胶可以在多个循环中键合并释放二价阳离子，而不会遭受任何功能性损失。此外，这些凝胶还选择性地捕获Fe ³⁺ 关于剩余的二价阳离子，开辟了在消化道中使用拟议的凝胶作为生物相容性螯合剂来对抗铁过度积累的可能性。