Biocompatible multihydroxyl hyperbranched polyglycidol (HPG) was covalently grafted from surfaces of multiwalled carbon nanotubes (MWNTs) by “grafting from" method based on in situ anionic ringopening polymerization

affording multifunctional MWNTsupported molecular amplifier with HPG content of 52 wt% (MWNTHPG).Subsequently

fluorescent molecules of rhodamine 6B and succinic anhydride were conjugated to the surfaces of MWNT-HPG by N

N′-dicyclohexylcarbodiimide (DCC) coupling and esterification

respectively

giving rise to fluorescent multicarboxylic nanotubes (MNWT-R6B-COOH).The functionalized MWNTs were characterized by the combination of TGA

FTIR

1H-NMR

SEM and TEM measurements.The asprepared MNWT-R6B-COOH was further modified with the specific peptide of D4 composed with amino acid sequence of leucine-alamine-arginine-leucine?leucine-threonine (Leu-Ala-Arg-Leu-Leu-Thr) which was previously designed against epidermal growth factor receptor (EGFR) by our pharmacy lab.We also used D4* that contains the same kind of amino acids as D4 but with different sequence to modify the MWNT-R6B-COOH as control.Through fluorescent microscope，MWNT-R6B-D4 was found to bind strongly and extensively to the EGFR high-expressing SPCAI cell

comparing with the MNWT-R6B-D4* and MWNT-R6B-COOH.The result suggests that such EGFR ligand-directed functionalized CNTs may be prospective and promising to become an efficient tumor cell targeted carrier for the cancer therapeutics.