Proteases have a fundamental role in maintaining physiological homeostasis, but their dysregulation results in severe activity imbalance and pathological conditions, including
cancer onset, progression, invasion, and
metastasis. This striking importance plus superior biological recognition and catalytic performance of
proteases, combining with the excellent physicochemical characteristics of nanomaterials, results in
enzyme-activated
nano-drug delivery systems (nanoDDS) that perform
theranostic functions in highly specific response to the
tumor phenotype stimulus. In the tutorial review, the key advances of
protease-responsive nanoDDS in the specific diagnosis and targeted treatment for
malignancies are emphatically classified according to the effector biomolecule types, on the premise of summarizing the structure and function of each
protease. Subsequently, the incomplete matching and recognition between
enzyme and substrate, structural design complexity, volume production, and toxicological issues related to the nanocomposites are highlighted to clarify the direction of efforts in nanotheranostics. This will facilitate the promotion of nanotechnology in the management of malignant
tumors.