Label-Free Detection of DNA Hybridization Based on MnO₂ Nanoparticles

Abstract

Nano-MnO₂/chitosan composite film modified glassy carbon electrode (MnO₂/CHIT/GCE) was fabricated and a DNA probe was immobilized on the electrode surface. The immobilization and hybridization events of DNA were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The EIS was applied to the label-free detection of the target DNA. The human immunodeficiency virus (HIV) gene fragment was successfully detected by this DNA electrochemical sensor. The dynamic detection range was from 2.0 × 10⁻¹¹ to 2.0 × 10⁻⁶ mol/L, with a detection limit of 1.0 × 10⁻¹² mol/L.

Keywords:

• DNA
• electrochemical impedance spectroscopy
• HIV gene
• nano-MnO₂

The financial support from the National Natural Science Foundation (No. 20675028), Foundation of the Ministry of Education of Henan (2008B150006) and 2008 Youth Foundation of the Ministry of Education of Henan Province (001135) are gratefully acknowledged.