Emerging hydrogel designs for controlled protein delivery.

Hydrogels have evolved into indispensable biomaterials in the fields of drug delivery and regenerative medicine. This minireview aims to highlight the recent advances in the hydrogel design for controlled release of bioactive proteins. The latest developments of enzyme-responsive and externally regulated drug delivery systems are summarized. The design strategies and applications of phase-separated hydrogel systems are also described. We expect that these emerging approaches will enable expanded use of hydrogels in biomedicine and healthcare.