Ammonium Carbamate Functionalization of Microgels for pH-Sensitive Loading and Release of Anionic and Cationic Molecules

摘要

The functionalization of porous microgels with polyamines is presented along with their par-tial conversion into carbamates with CO_2 for an ef? cient loading and release via electrostatic interactions. The resulting ammonium carbamate particles switch their charge from negative at pH 10 to positive at pH 5 and present a zwitterionic state at pH 7. Thus, they can easily be loaded with both cationic and anionic molecules. Furthermore, the ammonium carbamate functionalization allows for an ef? cient release at pH values between 5.0 and 7.4, whereas classical functionalization with carboxy- or amine-groups requires pH values below pH 4 or above pH 9. This versatile and easy-to-install functionaliza-tion has a great potential for various applications, such as the loading and release of drugs or nanoparticles from hydrogels.