Polyethyleneimine-Mediated Functionalization of Multiwalled Carbon Nanotubes:Synthesis,Characterization,and In Vitro Toxicity Assay

摘要

Polymer-functionalized carbon nanotubes hold great promise for their use in environmental and biomedical applications.In this work,polyethyleneimine(PEI)was covalently bonded to acid-treated multiwalled carbon nanotubes(MWCNTs)through amide bond formation.The amine groups of PEI on the surface of MWCNTs were then reacted with acetic anhydride or succinic anhydride to form MWCNTs with neutral or negative surface charges,respectively.The structural transformation,surface potential,and morphology of the functionalized MWCNTs were characterized by nuclear magnetic resonance,thermogravimetric analysis,zeta potential,and transmission electron microscopy.The functionalized MWCNTs are water-soluble and stable.In vitro cytotoxicity assays using both FRO cells(a human thyroid cancer cell line)and KB cells(a human epithelial carcinoma cell line)reveal that the biocompatibility of these functionalized MWCNTs is largely dependent on their surface potential.Neutral and negatively charged MWCNTs are nontoxic to both cell lines at a concentration up to 100 mu g/mL,whereas positively charged MWCNTs are toxic to FRO cells at 10 mu g/mL.The results of this study demonstrate that PEI-modified MWCNTs can be chemically modified to alter their surface charges and cytotoxicity,thereby significantly improving the biocompatibility of the materials for a variety of biomedical applications.