A simple and sensitive electrochemiluminescence spectrum measurement platform and spectrum-resolved ratiometric sensor for miroRNA-141 determination

Abstract

The electrochemiluminescence (ECL) spectral information is useful in ECL mechanism investigations, ratiometric ECL sensors and multi-analyte determinations. To overcome the shortcomings of low sensitivity in charge coupled devices (CCD) ECL spectrometer and low time efficiency for spectrum discrimination by using single band-pass filter (BPF) in one potential scan, a simple and sensitive ECL spectrum measurement platform is developed by placing a portable BPF array turntable device (with eleven measurement channels and one indicator channel) between the working electrode and photomultiplier in a conventional ECL analyzer. The systematic error due to the time dependent ECL intensity, which is the main obstacle for ECL spectrum measurement in wavelength scan mode, is neutralized by using the accumulated intensity for each channel in a group of spectrum measurement cycles. In a spectrum-resolved ratiometric ECL sensor for miroRNA-141 determination, near-infrared ECL emitter of methionine-stabilized Au nanoclusters (Met-Au NCs) is used as the tag and blue ECL emitter of g-C3N4 as the reference. The ratio of the total ECL intensity in near-infrared wavelength region (from Met-Au NCs) to that in blue wavelength region (from g-C3N4) is in linear correlation with the logarithmic concentration of microRNA-141 from 1 fM to 10 pM, with the limit of detection of 0.22 fM.