Simple Label-Free Femtomolar DNA Detection Based on a Nanostructure Composite Material: MWNT-Doped Poly(indole-6-carboxylic acid)

A nanostructure composite material consisting of poly(indole-6-carboxylic acid) (PICA) and carboxylic groups ended multiwall carbon nanotubes (MWNTs) was directly electrosynthesized from indole-6-carboxylic acid (ICA) monomer and MWNTs in one step, in which MWNTs was also used as supporting electrolytes. And a simple electrochemical sensor for recognition of target DNA related to hepatitis B virus (HBV) was directly fabricated by means of this composite material. The corresponding detection limit is 2.0 fmol L-1. This interesting conducting polymer with a very large surface area will provide new insights into how a biosensor is designed.