A new strategy to develop the disposable label-free immunosensor with electrochemiluminescent probing

In this paper, a new strategy to prepare the label-free immunosensor signaling with the electrochemiluminescence (ECL) of luminol will be reported. The gold nano-particles (AuNPs) functionalized indium tin oxide coated glass is used as the substrate for antibody immobilization. These AuNPs also improve the ECL behavior of luminol. This strategy for immunosensor construction is simple, fast, cheap, and with no requirements of expensive apparatus. For validating the practicability of this new strategy, with methamphetamine (MA) as target model, an MA sensor was built by immobilizing the MA-antibody onto the surface of previously mentioned substrate. The ECL intensity on resultant sensor, after the direct immuno-interaction, decreased proportional to the concentration of MA in a wide linear range from 2 to 500 ng mL−1 with a detection limit of 0.3 ng mL−1. This proposed sensor is sensitive, specific, stable and reliable. It has been successfully applied to detect the MA in spiked human serums.