TF and neoplasm: The resulting γCDP was subsequently coupled with 2,3-dimethylmaleic anhydride (DMA, as a pH-responsive moiety) [22,23], poly(ethylene glycol) (PEG, as a colloidal stabilizer) [6,7,24], and transferrin (Tf, as a target protein for Tf receptor-positive tumor cells) [2,6,25,26,27] (Figure 1b), denoted as γCDP-(DMA/PEG-Tf).