Regulating the work function and surface hydrophobicity of an indium tin oxide electrode for enhanced electrochemiluminescence analysis

Abstract

The electrochemical properties of the indium tin oxide (ITO) electrode were improved significantly by surface modification with ethephon and an ultrathin polydimethylsiloxane (PDMS) layer to regulate the work function and surface hydrophobicity of ITO. Based on this strategy, the electrochemiluminescence (ECL) intensity of tris(2,2′-bipyridyl)ruthenium (Ru(bpy)₃²⁺) and tri-n-propylamine (TPrA) in solution and on a microbead surface can be enhanced by 110 and 2 times, respectively. When using the modified electrode to detect nicotinamide adenine dinucleotide (NADH), the linear range (5–1000 μM) was increased dramatically in comparison with a bare ITO electrode, with a limit of detection of 1.65 μM. The modified electrode with improved electrochemical properties holds great potential for applications in ECL bioassays and imaging analysis.