Figure 3.

Peroxidase enzyme-triggered gene release: (a) Schematic diagram showing that the matrix metalloproteinase-2 (MMP2) enzyme-mediated cleavage of the linker leads to the release of Polyethylene glycol (PEG) and exposure of the cell penetrating peptide (CPP), facilitating the tumor-specific cellular uptake of DNA cargo and (b) drug and gene delivery strategy using an MMP2-sensitive peptide linking the PEG and polyethylenimine (PEI)-lipids. Reproduced with permission from [56]. Biomaterials, Elsevier, 2017.