Microplate Orbital Mixing Improves High-Throughput Cell-Based Reporter Assay Readouts

Reporter assays are commonly used for high-throughput cell-based screening of compounds, cDNAs, and siRNAs due to robust signal, ease of miniaturization, and simple detection and analysis. Among the most widely used reporter genes is the bioluminescent enzyme luciferase, which, when exposed to its substrate luciferin upon cell lysis, yields linear signal over a dynamic range of several orders of magnitude. Commercially available luciferase assay formulations have been developed permitting homogeneous, single-step cell lysis and reporter activity measurements. Assay conditions employed with these formulations are typically designed to minimize well-to-well luminescence variability due to variability in dispensing, evaporation, and incomplete sample mixing. The authors demonstrate that incorporating a microplate orbital mixing step into 96- and 384-well microplate cell-based luciferase reporter assays can greatly improve reporter readouts. They have found that orbital mixing using commercially available mix...