Supporting information Bio-functionalization of Multi-walled Carbon Nanotubes

1. Comparative study of carbon nanotube dispersion using surfactants Aqueous carbon nanotube dispersions were obtained by sonication tip using two cationic (DTAB and CTAB) and three anionic surfactants (SDDBS, SDS and SC). UV-Vis spectroscopy is a versatile method for characterizing the dispersion quality of CNTs in a solution. Bundles of MWCNTs are not active in the wavelength region between 200-1100 nm and only individual CNTs exhibit characteristic bands. UV-vis absorption spectra of these four samples were measured by subtracting the absorbance values of 1wt% surfactants from that of MWCNTs dispersion. Fig.1S (a) and figure 1S (b) illustrate the UV-vis spectra of these samples and their suspension photographs after centrifugation, respectively. a) b)