Irreversible blocking of ion channels using functionalized single-walled carbon nanotubes

We demonstrate irreversible blocking of ion channels using single-wall carbon nanotubes (SWNTs) functionalized with 2-aminoethylmethane thiosulfonate (MTSET). In contrast, as-produced and purified SWNTs exhibit reversible blocking, indicating that the MTSET molecule attached to SWNTs chemically interacts with the cysteine groups in the ion channels. Functionalization of SWNTs with MTSET is inferred from Fourier transform infrared (FTIR) spectroscopy, which clearly shows absorptions due to -CH stretching and deformation modes, and decrease in intensity of the -COOH line due to reaction of acid functionalized SWNTs with the basic N-CH3 end of the MTSET molecule.