Metal-coordination cross-linking can bypass traditional stoichiometric limits for macromolecular material assembly.
October 11, 2019
MIT researchers including Prof. Niels Holten-Andersen have recently published a PNAS paper that reports how metal-coordination cross-linking can bypass traditional stoichiometric limits for macromolecular material assembly. Specifically, they use metal-coordinated hydrogels to demonstrate how to prevent excess cross- linker from dissolving macromolecular networks by using hydroxide ion competition to buffer excess metal ions and thereby protect the network. Additionally they use simulations to develop a thermodynamic framework that predicts the coupled dynamic equilibria conditions that result in this competition-induced network protection effect. This is a critical innovation, not only because it demonstrates how to overcome classical limits on macromolecular material cross-link stoichiometry, but also because it reveals an intrinsic robustness in the self-assembly of metal-coordinate networks, shedding additional light on the emerging prevalence of metal coordination in biological materials.