Programming Gels Over a Wide pH Range Using Multicomponent Systems

Multicomponent hydrogels offer a tremendous opportunity for preparing useful and exciting materials that cannot be accessed using a single component. Here, we describe an unusual multi-component low-molecular weight gelling system that exhibits pH-responsive behavior involving cooperative hydrogen bonding between the components, allowing it to maintain a gel phase across a wide pH range. Unlike traditional acid-triggered gels, our system undergoes a change in the underlying molecular packing and maintains the β-sheet structure both at acidic and basic pH. We further establish that autonomous programming between these two gel states is possible by an enzymatic reaction which allows us to prepare gels with improved mechanical properties.