MMP2 and neoplasm: Han and his colleagues proposed a size‐shrinkage drug delivery system based on a polysaccharide‐modified dendrimer with tumor microenvironment responsiveness, formed by conjugating the terminal glucose of hyaluronic acid (HA) to the superficial amidogen of poly(amidoamine) (PAMAM), using a matrix metalloproteinase‐2 (MMP‐2)‐cleavable peptide (PLGLAG) via click reaction[98] (Figure 7B).