Gold nanoparticles functionalized poly(3,4-ethylenedioxythiophene) thin film for highly sensitive label free DNA detection

Abstract

We report the easy fabrication of gold nanoparticles (AuNPs) functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) film on a glassy carbon (GC) electrode for label free DNA sensing in the presence of a [Ru(NH₃)₆]³⁺ (RuHex) redox probe in Tris–HCl buffer. Cyclic voltammetry (CV) and chronocoulometry (CC) techniques were employed for interrogating the electrochemical behavior of the modified GC electrode and DNA sensing. Incorporation of the AuNPs in the PEDOT matrix induces 10-fold increase in conductivity and also eliminates the direct functionalization of the native polymer for DNA attachment. The modified films were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, Atomic Force Microscopy (AFM), CV and CC techniques. The observed dynamic detection range is 1.0 × 10⁻¹³ to 1.0 × 10⁻¹⁵ M, with the lowest detection limit (3σ/b) of 2.6 × 10⁻¹⁶ M.