Responsive polymer networks are vital to advances in modern materials. 1,2-dithiolanes, a five-membered cyclic disulfide, present an opportunity for continued development in this field. Owing to their characteristic ring strain, these intrinsically photoreactive moieties are capable of direct photopolymerization without the need for exogenous initiator. Furthermore, the resulting linear disulfide remains dynamic post-polymerization, enabling user-defined transformations within networks. Multifunctional monomers and macromers decorated with dithiolanes, specifically lipoic acid, have shown promise in a variety of applications. Highlighted here are poly (ethylene glycol) based dithiolane hydrogels, a dynamic gel system capable of photopolymerization with and without photoinitiator. Post-polymerization dynamic transformations enable direct user-controlled changes to the cell microenvironment, as well as enabling the fabrication of anisotropic microgels in a higher-throughput method. This crosslinking scheme represents important advances in photodynamic hydrogels to more directly probe mechanobiological questions in tissue engineering.
