English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

When a highly charged globular macromolecule, such as a dendriticpolyelectrolyte or charged nanogel, is immersed into a physiologicalelectrolyte solution, monovalent and divalent counterions from the solutionbind to the macromolecule in a certain ratio and thereby almost completelyelectroneutralize it. For charged macromolecules in biological media, thenumber ratio of bound mono- versus di-valent ions is decisive for the desiredfunction. A theoretical prediction of such a sorption ratio is challengingbecause of the competition of electrostatic (valency), ion-specific, andbinding saturation effects. Here, we devise and discuss a few approximatemodels to predict such an equilibrium sorption ratio by extending and combiningestablished electrostatic binding theories such as Donnan, Langmuir, Manning aswell as Poisson-Boltzmann approaches, to systematically study the competitiveuptake of mono- and di-valent counterions by the macromolecule. We compare andfit our models to coarse-grained (implicit-solvent) computer simulation data ofthe globular polyelectrolyte dendritic polyglycerol sulfate (dPGS) in saltsolutions of mixed valencies. The dPGS has high potential to serve inmacromolecular carrier applications in biological systems and at the same timeconstitutes a good model system for a highly charged macromolecule. We finallyuse the simulation-informed models to extrapolate and predict electrostaticfeatures such as the effective charge as a function of the divalent ionconcentration for a wide range of dPGS generations (sizes).

Competitive sorption of mono- versus di-valent ions by highly charged globular macromolecules