Kinetic Locking of pH-Sensitive Complexes for Mechanically Responsive Polymer Networks

Achieving sensitive and reversible responsivity over physiologically relevant pH ranges (4.5-7.5) remains of great interest for the design of next-generation autonomous drug delivery devices. Developing molecular interactions that are responsive within this pH range would enable targeted drug delivery at tumor sites or within inflamed or arthritic joints, where these changes in pH occur. Here, we demonstrate pH-responsive molecular interactions by the kinetic locking of host-guest complexes. Employing these complexes as dynamic crosslinks within polymer networks gives rise to materials with highly pH-responsive mechanical and viscoelastic properties. These systems further exhibit pH-dependent release of cargo, offering a self-responsive approach toward targeted drug delivery.