Immobilization of Histidine-Tagged Proteins on Functionalized Carbon Nanotubes

Abstract

We report herein a general method enabling specific immobilization and orientation of histidinetagged proteins on multiwalled carbon nanotubes. We describe the design and the synthesis of a series of seven water-soluble molecules containing an increasing number of aromatic rings link to a nitrilotriacetic acid (NTA)polar head. Among the molecules prepared, Tbf-NTA built with a tetrabenzofluorenyl group was found to induce a stable suspension of carbon nanotubes in water. Adsorption of this new reagent (Tbf-NTA)on multiwalled carbon nanotubes was demonstrated using transmission electron microscopy and UV/visible spectroscopy. Chelation of nickel ions by multiwalled carbon nanotubes coated with Tbf-NTA was also evidenced by energy dispersive X-ray microanalysis. Finally, immobilization of histidine-tagged DNA gyrase A protein on the surface of carbon nanotubes functionalized by Ni/Tbf-NTA complexes could be visualized by electron microscopy whereas little protein binding was observed in the absence of reagent.