As shown in Figure 7A, irregular pythio-MWNT aggregates were observed for the SAMs before immersion in the Cyt c. After the SAMs were immersed in the Cyt c solution for 1 h, dot-like aggregates could be distinguished from the AFM image, with the sizes of the aggregates increased (Figure 7B). These aggregates could be attributed to the Cyt c adsorbed on the surface

of pythio-MWNTs. A higher resolution AFM photo was inserted in Figure 7B, from which tubular lines of the nanotubes could be observed. Figure 7 AFM images for the SAMs of pythio-MWNTs. (A) Before and (B) after adsorption of Cyt c. (C, D) Height profiles corresponding to the lines in the AFM images of (A) and (B), respectively. The height profiles obtained from the AFM images were shown in Figure 7C,D. These curves indicated Selleckchem Go6983 that the height of most aggregates in the SAMs of pythio-MWNTs was around 3 nm. When the AZD6738 mw protein was adsorbed on the SAMs, the average height of the aggregates increased, with some domains reaching as high as 6 nm. These data further confirmed that the Cyt c was adsorbed on the surface of pythio-MWNTs. Conclusions We have demonstrated preparation of the self-assembled monolayers of pyridylthio-functionalized multiwalled carbon nanotubes on the gold substrate surface, which could be used as a support to immobilize cytochrome c to form bio-nanocomposites. The surface coverage for the SAMs of pythio-MWNTs was about

5.2 μg/cm2 and that of the Cyt c was about 0.29 μg/cm2. It was suggested that the protein was adsorbed on the surface of the nanotubes through the hydrophobic interaction and protein affinity between the Cyt c and pythio-MWNTs. Acknowledgments The authors are grateful for the National Science Foundation of China (21073044) and the Program for

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