Biotin-avidin as a protease-responsive cap system for controlled guest release from colloidal mesoporous silica

Tell your guests when it's time to go: When avidin caps are attached to biotinylated colloidal mesoporous silica, the four subunits of the protein avidin can each bind to a biotin moiety attached to the surface (see picture). The resulting material is a promising candidate for the design of smart detergents or drug-delivery systems. The caps can be opened to release guest molecules by controlled enzymatic hydrolysis of the protein.