Visual microarray detection for human IgE based on silver nanoparticles

Abstract

A rapid, visual protein detection method of human immunoglobulin E (hIgE) was developed for 96-well microplate arrays by using aptamer modifying silver nanoparticles. An aptamer specifically recognizing IgE and biotinylated oligonucleotides were used to modify AgNPs and the resulting nanoprobes were employed to assay model analyte hIgE. When addition of the analyte as well as the probes to the microplate array on which Goat anti-human IgE was first immobilized, the signal of this “sandwich” format was further amplified by silver enhancement technique based on silver ions reductive reagents and achieved a visual dots in the microplates. To achieve quantitative analysis, a series of gradient concentration streptavidin (SA) was immobilized in the same well. As a result, an internal standard curve was plotted by the signal of different concentration of SA based on streptavidin-biotin coupling reaction. With the help of this curve, a quantitative detection of IgE was established and a detection limit of 20ngmL−1 could be obtained. The presented method was further carried out for detection of human serum samples and relative consistent results were found.