Electrogenerated chemiluminescence from a phenyleneethynylene derivative and its ultrasensitive immunosensing application using a nanotubular mesoporous Pt-Ag alloy for signal amplification

Abstract

Electrogenerated chemiluminescence (ECL) of a novel phenyleneethynylene derivatives [4,4'-(2,5-dimethoxy-1,4-phenylene)bis(ethyne-2,1-diyl) dibenzoic acid; P-acid] possessing carboxylic acid groups at the para positions in aqueous solutions and its first immunosensing application are studied. Nanotubular mesoporous Pt-Ag alloy nanoparticles are first used to fabricate the ECL immunosensor as a signal amplification carrier. Absorption, photoluminescence, cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy are used as powerful tools to characterize P-acid, Pt-Ag alloy nanoparticles, and the fabrication process of the immunosensor. P-acid exhibits two ECL peaks at -1.07 (ECL-1) and 0.64 (ECL-2) V in air-saturated pH 7.4, 0.1 M PBS containing 0.1 M KCl during the cyclic sweep between 1.51 and -2.67 V at 0.1 V s -1; the ECL mechanism of these two ECL peaks is demonstrated. The electron-transfer reaction between electrochemically oxidized P-acid and tri-n-propylamine (TPrA) radical cation is also demonstrated to produce high ECL emissions and used to develop an ultrasensitive ECL immunosensor. In addition, a Pt-Ag alloy nanoparticles amplification carrier for protein ECL analysis is applied for improvement of the detection sensitivity. Thus, this ECL immunosensor exhibits high sensitivity, good reproducibility, rapid response, and long-term stability. © 2012 WILEY-VCH Verlag erlag GmbH & Co. KGaA, Weinheim.