The expression and distribution of enzymes differ by the types and states of cells, tissues, and organs, thus leading to diverse extracellular and intracellular environments. Using an enzymatic reaction to convert precursors into hydrogelators that self-assemble into nanofibers as the matrices of the hydrogel, one can control the delivery, function, and response of a hydrogel according to a specific biological condition or environment, thus providing an accessible route to create sophisticated materials for biomedicine. In this talk, we will discuss the use of enzymes to trigger and control the self-assembly of small molecules for hydrogelation, which takes place in vitro or in vivo, extra- or intracellularly, offers a new strategy for detecting the activity of enzymes, screening for enzyme inhibitors, typing bacteria, drug delivery systems, enhancing the activity and stability of enzymes, and controlling the fate of cells.

Scheme. Enzyme triggered self-assembly and hydrogelation in vivo.