TfR-T12 binds to the TfR and is subsequently internalized into TfR-expressing cells[1]. TfR-T12 is a synthetic peptide obtained by phage display, and is able to bind a different site on TfRs compared with transferrin. TfR-T12 can be chemically conjugated with a pegylated lipid derivative, 3-(N-succinimidyloxyglutaryl)aminopropyl- polyethyleneglycol(2000)- carbamyl distearoyl phosphatidylethanolamine (NHS-PEG2000-DSPE), and used as a functional material to construct the multifunctional lipid vesicles[2].