MMP2 and neoplasm: Hydrophobic IR780 and hydrophilic APP were connected to the MMP‐2 responsive nanoplatform via a methionine fragment and a PLGLAG peptide, respectively (Figure 4a,b).[129] The MMP‐2 responsive delivery system had two features: the nanocarriers were responsive to over‐expressed MMP‐2 in the tumor microenvironment to release the therapeutic agents in tumor cells to minimize their systemic side effect; MMP‐2 responsive cleavage shrank the nanostructures from a size of 151.1–34.12 nm to enhance their deep penetration within the tumor tissues (Figure 4c).