Structure of swollen hollow polyelectrolyte nanogels with inhomogeneous cross-link distribution.

Hypothesis: Recently, it has become possible to synthesize hollow polyelectrolyte nano- and microgels. The shell permeability can be controlled by external stimuli, while the cavity can serve as a storage place for guest molecules. However, there is a lack of a detailed understanding at the molecular level regarding the role of the network topology, inhomogeneities of the distribution of cross-links, and the impact of the electrostatics on the structural response of hollow microgel to external stimuli.

Swelling and Collapse of Cylindrical Polyelectrolyte Microgels.

In this study, we propose computer simulations of charged cylindrical microgels. The effects of cross-linking density, aspect ratio, and fraction of charged groups on the microgel swelling and collapse with a variation in the solvent quality were studied. The results were compared with those obtained for equivalent neutral cylindrical microgels.

Interpolyelectrolyte Complex Dissociation vs Polyelectrolyte Desorption from Oppositely Charged Surface upon Salt Addition.

The structure of complexes formed by oppositely charged polyelectrolytes and adsorbed layers on charged surfaces is sensitive to low-molecular-weight salt. Furthermore, if the concentration exceeds some threshold value, the complexes and adsorbed chains can be "dissolved". This is due to the screening of the electrostatic interactions between charged units.

Distribution of Ionizable Groups in Polyampholyte Microgels Controls Interactions with Captured Proteins: From Blockade and "Levitation" to Accelerated Release.

A striking discovery in our work is that the distribution of ionizable groups in polyampholyte microgels (random and core-shell) controls the interactions with the captured proteins. Polyampholyte microgels are capable to switch reversibly their charges from positive to negative depending on pH. In this work, we synthesized differently structured polyampholyte microgels with controlled amounts and different distribution of acidic and basic moieties as colloidal carriers to study the loading and release of the model protein cytochrome c (cyt-c).