Photomultiplier based plate-readers vs. CCD imaging based plate-readers

Edward Dell, BMG Labtech

“Although photomultiplier based plate-readers offer increased sensitivity compared to CCD imaging based plate-readers, they take longer to collect data from a microtitre plate. How do your customers balance throughput versus sensitivity when considering which plate-reader to purchase?”

Edward Dell, International Marketing Director, BMG Labtech:

Edward Dell, BMG Labtech

This is a good question and one that is asked often. Significant improvements in speed and sensitivity of photomultiplier tube (PMT) based readers make this choice more difficult than ever. Mechanical transport systems are much faster and more precise than their counterparts of even five years ago, reducing plate read times. In addition, photomultiplier measurement electronics have also improved, resulting in sensitivity increases. Greater sensitivity means less time to integrate the signal from a well for an acceptable Z and assay window. Therefore in some assays, modern photomultiplier-based microplate readers (particularly ones with simultaneous dual emission detection) can outperform CCD based readers in sensitivity and speed.

My suggestion to researchers is to first determine the application(s) that will be performed with the instrument. Applications that require a high degree of sensitivity, for example fluorescence polarisation or time-resolved fluorescence resonance energy transfer (TR-FRET), may be better served with a PMT-based microplate reader, whereas robust applications with single channel emission, such as fluorescence intensity or in some cases luminescence, may be read more quickly using a CCD based reader, as long as the data quality is sufficient. Ultimately the application, needed speed, and data quality will drive the decision.