SIK2 and ovarian cancer: Upon activation by salt‐inducible kinase 2 (SIK2) overexpressed in ovarian cancers, hydrogelators in the HG‐9‐91‐01‐coassembled nanofibers will be efficiently converted to their hydrophilic phosphates, triggering the disassembly of the nanofibers and the sustained release of HG‐9‐91‐01.