Work

Polyacrylamide Network Permeation in Hyaluronic Acid and Poly- l -lysine Complex Coacervates

Year: 2026

Type: article

Abstract: For many biomolecular condensates, complex coacervation occurs in a viscoelastic medium, which can permeate the droplets and regulate phase separation. Here, we study the permeation of complex coacervate droplets composed of hyaluronic acid (HA) and poly-l-lysine (PLL) inside synthetic polyacrylamide (PAM) hydrogels (160–2200 Pa). From the confocal images of fluorescently conjugated complex coacervate phases in the background of a separately labeled gel, we measure the intensity-derived normalized gel concentration λg. λg rose from ∼0.4 in the soft gels to ∼0.6 in the stiffest gels, showing that the extent of permeation is dependent on elasticity. By varying the solvent ionic strength (10–280 mM) and loading polyelectrolyte concentration (2–40 g L–1), we find that λg is maximized near the critical ionic strength and at the lowest polyelectrolyte loading concentration. Straightforward theory is used to explain the overall physical trends, showing that coacervation in a crosslinked network is governed by a competition between network elasticity and excluded volume interactions.

Source: Macromolecules

DOI: 10.1021/acs.macromol.6c00699

Authors: Kai R. Yamagami, Ping-Huan Tsai, Charles E. Sing, Svetlana Morozova

Institutions: Case Western Reserve University, University of Illinois Urbana-Champaign

Language: English

Topic: Electrostatics and Colloid Interactions

Subfield: Physical and Theoretical Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funder: Division of Materials Research