Title

Layer-by-Layer Fabrication and Characterization of DNA-Wrapped Single-Walled Carbon Nanotube Particles

Document Type

Article

Publication Date

6-21-2005

Publication Title

Langmuir

Abstract

Carbon nanotubes have been proposed as support materials for numerous applications, including the development of DNA sensors. One of the challenges is the immobilization of DNA or other biological molecules on the sidewall of carbon nanotubes. This paper introduces a new fabrication of DNA−carbon nanotubes particles using the layer-by-layer (LBL) technique on single-walled carbon nanotubes (SWCNTs). Poly(diallyldimethylammonium) (PDDA), a positively charged polyelectrolyte, and DNA as a negatively charged counterpart macromolecule are alternatively deposited on the water-soluble oxidized SWCNTs. Pure DNA/PDDA/SWCNTs particles can be prepared and separated by simple unltracentrifugation. The characterization of DNA/PDDA/SWCNTs particles was carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV−visible spectroscopy, Raman spectroscopy, and thermogravimetric analysis (TGA). An electrode modified by the DNA/PDDA/SWCNTs particles shows a dramatic change of the electrochemical signal in solutions of tris(2,2‘-bipyridyl)ruthenium(II) ((Ru(bpy)32+) as a reporting redox probe. A preliminary application of the DNA-modified carbon nanotubes in the development of DNA sensors used in the investigation of DNA damage by nitric oxide is presented.

Comments

This research is supported by a pilot grant from the American Cancer Society (Ohio Division, Cuyahoga office), by an EFFRD grant from CSU, and in part by a grant from the U.S. Department of Energy.

DOI

10.1021/la050581b

Volume

21

Issue

13