Electroactive gold nanoparticles/polyaniline/polydopamine hybrid composite in neutral solution as high-performance sensing platform

Abstract

A novel sensing platform based on gold nanoparticles/polyaniline/polydopamine (AuNPs/PANI/pDA) hybrid composite was proposed. The AuNPs/PANI/pDA hybrid composite was facilely synthesized by a two-step reaction, including the spontaneous self-polymerization of dopamine and the formation of AuNPs with both pDA and aniline as the reducing agent in the presence of poly(vinyl pyrrolidone) (PVP). As AuNPs associated with PVP provided negative charges for anionic doping, the resulting AuNPs/PANI/pDA composite exhibited good electroactivity in neutral solution. Meanwhile, AuNPs permitted a facile flow of electrons cross the PANI matrix during the electrochemical process and endowed the hybrid composite with enhanced catalytic ability. To investigate the electrocatalytic capability, the AuNPs/PANI/pDA hybrid composite modified electrode was used to electrocatalyze the oxidation of ascorbic acid (AA). Under optimized conditions, the sensor showed a fast amperometric response (4 s), a good linear response toward AA over a wide range from 1.0 × 10⁻⁶ to 1.9 × 10⁻³ M, and a low detection limit of 4.0 × 10⁻⁷ M. The current established sensing platform based on AuNPs/PANI/pDA hybrid composite should hold huge potential for loading enzymes, proteins, DNA, etc.