Figure 1. Detection of target RNAs using branched DNA technology.

Branched DNA technology for RNA detection can be coupled with confocal microscopy or flow cytometry. Target RNAs are first bound by pairs of Target Probes. Typically, twenty sets of target probe pairs are designed per target RNA. The Pre-Amplifier DNA only binds target probe pairs that are bound to target RNAs in the correct orientation; this greatly limits the signal to noise ratio. Pre-Amplifier DNAs are then bound by Amplifier DNAs and subsequently by Label Probes. This process results in the labeling of target RNAs by up to 8,000 fluorophores.