Polyampholyte microgels as container systems to entrap guest molecules like proteins, dyes or nanoparticles has been intensively studied in the past years and has also drew great attention in the field of bio-medical application. This kind of smart materials are extremely interesting due to their facile functionalization and their high bio-compatibility. Additionally, the functionality of such microgles can be controlled by the applied monomers and crosslinker density during the synthesis. In this way the properties of the particles and the response to outer stimuli can be tuned. Proteins tend to attach into microgel systems through chemical- (covalent) or physical- (electrostatic) binding. The latter one has attracted more attention since it offers the opportunity to achieve an efficient binding and triggered release in the surrounding medium via electrostatic interactions.<br/>In this content we aimed to synthesize polyampholyte micorgels with different structures (random or core-shell distribution of ionizable groups and Janus-like microgels). Furthermore the influence of outer stimuli (pH, temperature, salt concentration and diffrent medium) to the interaction between the model protein cytochrome c and the synthesized microgels was studied. Also, we demonstrate for the first time that the distribution of the ionizable groups in the microgels (random vs. core-shell) also has a strong influence to the release procedure of the proteins. Once the proteins were entrapped inside the microgel containers at pH 8 by electrostatic attraction forces (protein and microgels are oppositely charged at pH 8), they remain strongly bound and show no leaching effects for months. An effective triggered release can be achieved by variation of the pH value (from pH 8 to pH 3, at pH 3, protein and microgels are equally charged) of the surrounding medium. Computer simulations were carried out to support the experimental results of the electrostatic nature of uptake and release of the proteins and their trapping by core-shell microgels.

Distribution of ionizable groups in polyampholyte microgels controls interactions with captured proteins: From blockade and "levitation" to accelerated release

255th National Meeting (2018)

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