Engineered selective biotoxin‐binding hydrogels for toxin sequestration

Abstract

The development of synthetic selective membranes that separate materials of similar sizes, charges, and/or polarities remains a difficult challenge, and looking towards biology provides inspiration for new designs. In this work, a series of cholera toxin binding peptides (CTBPs) are identified, spanning a range of binding inhibitions, and integrated into chemically cross‐linked cholera toxin binding gels (CTBGs) via thiol‐Michael polycondensation reactions. All gels demonstrate rheological profiles consistent with elastic solids. The CTBGs are probed via small‐angle neutron scattering and exhibit a correlation length, <jats:italic>ξ</jats:italic>, smaller than most proteins (1.3–2.5 nm). Thus, an effective entropic mesh is formed to block non‐targeted proteins. However, the CTBGs have a dynamic mesh size, Ξ, that is larger than cholera toxin (CT) to allow the transport of target proteins. The CTBGs with the highest binding inhibitions both show high selectivity and permeation of CT, rejecting all other tested proteins. In total, two new highly selective CTBGs are synthesized and validated for use in cholera toxin remediation. Together, this platform demonstrates the wide applicability of selectively‐diffusive materials for difficult separations.