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Large Changes in Protonation of Weak Polyelectrolyte Brushes with Salt Concentration-Implications for Protein Immobilization.

ABSTRACT: We report for the first time that the protonation behavior of weak polyelectrolyte brushes depends very strongly on ionic strength. The pKa changes by one pH step per order of magnitude in salt concentration. For low salt concentrations (?1 mM), a very high pH is required to deprotonate a polyacidic brush and a very low pH is required to protonate a polybasic brush. This has major consequences for interactions with other macromolecules, as the brushes are actually almost fully neutral when believed to be charged. We propose that many previous studies on electrostatic interactions between polyelectrolytes and proteins have, in fact, looked at other types of intermolecular forces, in particular, hydrophobic interactions and hydrogen bonds.

SUBMITTER: Ferrand-Drake Del Castillo G

PROVIDER: S-EPMC7467743 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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Large Changes in Protonation of Weak Polyelectrolyte Brushes with Salt Concentration-Implications for Protein Immobilization.

Ferrand-Drake Del Castillo Gustav G Hailes Rebekah L N RLN Dahlin Andreas A

The journal of physical chemistry letters 20200618 13

We report for the first time that the protonation behavior of weak polyelectrolyte brushes depends very strongly on ionic strength. The p<i>K</i><sub>a</sub> changes by one pH step per order of magnitude in salt concentration. For low salt concentrations (∼1 mM), a very high pH is required to deprotonate a polyacidic brush and a very low pH is required to protonate a polybasic brush. This has major consequences for interactions with other macromolecules, as the brushes are actually almost fully ...[more]

PMID: 32515599

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