Open Access Nano Express

Self-assembled monolayers of pyridylthio-functionalized carbon nanotubes used as a support to immobilize cytochrome c

Qing Sun1, Jiang Liu1, Hong-Xiang Huang2, Meng Chen1 and Dong-Jin Qian1*

Author Affiliations

1 Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, China

2 Department of Macromolecular Science, Fudan University, 220 Handan Road, Shanghai, 200433, China

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Nanoscale Research Letters 2013, 8:63  doi:10.1186/1556-276X-8-63

Published: 7 February 2013

Abstract

Self-assembled monolayers (SAMs) of pyridylthio-functionalized multiwalled carbon nanotubes (pythio-MWNTs) have been constructed on the gold substrate surface, which were used as a support to immobilize cytochrome c (Cyt c). The assembly processes of the SAMs and adsorption of Cyt c were monitored by using quartz crystal microbalance (QCM). Based on the frequency change of the QCM resonator, the surface coverage for the SAMs of pythio-MWNTs was estimated to be about 5.2 μg/cm2, and that of the Cyt c adsorbed was about 0.29 μg/cm2. For the gold electrode modified by the SAMs of pythio-MWNTs-Cyt c, a quasi-reversible redox wave was recorded with the cathodic and anodic potentials at about −0.55 and −0.28 V vs Ag/AgCl, respectively. Compositions and morphologies of the SAMs before and after immobilization of Cyt c were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy.

Keywords:
Carbon nanotube; Self-assembled monolayer; Protein; Adsorption; Morphology