“…Polyethylene glycol (PEG)-modified, phospholipid micelles coating is favourable since this can results in satisfactory solubility and stability in aqueous solutions, well biocompatibility, and also with prolonged blood circulation time when they are delivered intravenously. The PEG can be modified for bioconjugation of various moieties such as antibody, oligonucleotides, and peptides and may allow for molecular specific intracellular targeting of specific proteins and nucleic acid (Gupta & Gupta, 2005;Kohler et al, 2004;Kumagai et al, 2007;Lee et al, 2006Lee et al, , 2007aMikhaylova et al, 2004;Nitin et al, 2004;Veiseh et al, 2005). PEG-coated MNP has the disadvantage such as limited binding sites available for further ligand binding (Gupta & Gupta, 2005), and the coating thickness can significantly affect their relaxivity (Laconte et al, 2007).…”