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arXiv · 2607.14061

Gelation of functional peptides by trivalent cations at the air-water interface

Stephen A. Crane·Felipe Jimenez Angeles·Monica Olvera de la Cruz·Ivan J. Dmochowski·Kathleen J. Stebe
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Abstract

We report a mechanism for gelation at fluid interfaces driven by multivalent-cation-mediated bridging. At the air-water interface, peptides with bound lanthanide cations undergo a coordination-geometry transition that converts the metal from a single-peptide bound state to a multi-peptide bridging state, driving charge inversion and gel formation. Surface adsorption and non-ideal interfacial electrostatics are implicated in this transition. The gel is stabilized by reversible metal-ligand coordination bonds that resist bulk salt screening, fundamentally distinct from electrostatic charge-inversion gelation in proteins. This reveals the breakdown of the peptide's coordinating sphere as a distinct pathway for interfacial gelation, independent of the diffuse electrostatic mechanisms governing bulk protein aggregation.

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Stephen A. Crane, Felipe Jimenez Angeles, Monica Olvera de la Cruz, Ivan J. Dmochowski, Kathleen J. Stebe. 2026-07-15. Gelation of functional peptides by trivalent cations at the air-water interface. https://arxiv.org/abs/2607.14061

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