BADGE, Beads Array for the Detection of Gene Expression, a high-throughput diagnostic bioassay.

Several methods are presently available for gene expression analysis. However, few of them are suitable for detection of moderate numbers of genes in thousands of samples with high speed and low cost. There is great demand for such a method for use in diagnostics and screening. To address this need, we have developed an assay for gene expression analysis using microspheres and a fluidic instrument made by Luminex. The assay is named Beads Array for the Detection of Gene Expression (BADGE). BADGE can monitor up to 100 genes in a single reaction, and it takes only 1 h to hybridize and <20 sec to read the results of all 100 genes in a sample for the detection process. For the genes detected in five independent replicate experiments, the standard deviation was <35% of the mean. We have monitored multiple pathogenesis-related genes simultaneously in chemical-treated and control Arabidopsis samples employing the BADGE assay. The data were compared with those obtained from an established technology, Affymetrix GeneChip. The changes in expression profiles were very similar. Our study showed that the BADGE assay was capable of profiling expression of multiple genes at affordable cost and rapid speed.