Cisbio´s HTRF cortisol assay performed on the PHERAstar
Franka Ganske, Jean-Luc Tardieu and Francois Degorce
BMG LABTECH, Germany. Cisbio Bioassays, Codolet, France.
Recently Cisbio developed an assay to determine the activity of 11 beta-HSD1 using HTRF® technology. HTRF® (Homogeneous Time-Resolved Fluorescence) is based on TR-FRET (time-resolved fluorescence resonance energy transfer), a combination of FRET chemistry and the use of fluorophores with long emission halflives (Europium, Eu3+). FRET uses two fluorophores, a donor and an acceptor. Excitation of the donor by an energy source (e.g. flash lamp or laser) triggers an energy transfer to the acceptor if they are within a given proximity to each other. The acceptor in turn emits light at a given wavelength. BMG LABTECHs PHERAstar (Figure 1) is a multifunctional plate reader that combines rapid plate reading necessary for high throughput screening (HTS) with the enhanced performance and sensitivity needed to read small fluid volumes. The PHERAstar has been designed to read all HTS detection modes (fluorescence intensity, time-resolved fluorescence, fluorescence polarization, luminescence, AlphaScreen and absorption) in all plate formats up to 1536 wells. To meet the HTRF® requirements the PHERAstar uses a unique HTRF®-specific optical module that can measure two emission signals simultaneously.