Surface‐Assisted Self‐Assembly of a Hydrogel by Proton Diffusion

Abstract

Controlling supramolecular growth at solid surfaces is of great importance to expand the scope of supramolecular materials. A dendritic benzene-1,3,5-tricarboxamide peptide conjugate is described in which assembly can be triggered by a pH jump. Stopped-flow kinetics and mathematical modeling provide a quantitative understanding of the nucleation, elongation, and fragmentation behavior in solution. To assemble the molecule at a solid-liquid interface, we use proton diffusion from the bulk. The latter needs to be slower than the lag phase of nucleation to progressively grow a hydrogel outwards from the surface. Our method of surface-assisted self-assembly is generally applicable to other gelators, and can be used to create structured supramolecular materials.

Light‐Responsive Arylazopyrazole Gelators: From Organic to Aqueous Media and from Supramolecular to Dynamic Covalent Chemistry

“…Benzene-1,3,5-tricarboxamide (BTA) derivatives establishedb yM eijer and co-workers are distinguished examples of tripodal monomers with benzene as the core and variable functionalities connected to the core by amide bonds. [68] The intermolecularh ydrogen bondingp rovided by the amides initiates the self-assembly.B ya ppending dif-ferent arms to the BTAc ore, diverses oft materials and applications, including hydrogels, [69,70] protein recognition, [71,72] imaging, [67] and catalysis [73] were developed. Similar to BTA, cyclohexane-1,3,5-tricarboxamide (CTA) also affords intermolecular face-to-face hydrogen bondinga nd in addition, displays conformational flexibility.T he flexible cyclohexane core permits the optimal stackingo ft he LMWGsa nd formsa ne xtended supramolecular polymer.…”

“…The intermolecular hydrogen bonding provided by the amides initiates the self‐assembly. By appending different arms to the BTA core, diverse soft materials and applications, including hydrogels, protein recognition, imaging, and catalysis were developed. Similar to BTA, cyclohexane‐1,3,5‐tricarboxamide (CTA) also affords intermolecular face‐to‐face hydrogen bonding and in addition, displays conformational flexibility.…”

Protein-induced low molecular weight hydrogelator self-assembly through a self-sustaining process

“…In the quest to design materials possessing high performance features similar to those found in biological tissues, an absolute prerequisite for success is to control self-assembly processes both spatially and temporally 2. Within this framework, the use of (bio)catalysts to trigger the localization of the self-assembly of low molecular weight hydrogelators (LMWH) has proven to be highly interesting 3. Indeed, enzymes can catalyze the transformation of non-assembling entities into self-assembling ones, rapidly and with high specificity 4.…”

Stimuli‐Responsive Supramolecular Hydrogels and Their Applications in Regenerative Medicine

“…One of the most effective methods to initiate supramolecular hydrogelation is the use of pH as a stimulus since small amount of acid or base can provide large pH-shift through rapid diffusion of protons or hydroxide ions. [139–142] In general, the reversible protonation/deprotonation of an acidic/basic group increases the solubility of the hydrogelators in aqueous medium upon change in pH, which in turn can result in the formation of supramolecular hydrogels above their CGC. Furthermore, change in pH is also known to significantly affect the intensity and strength of hydrogen bonds between the hydrogelators.…”