Filters vs. Monochromators -
There were always two options to filter light into monochromatic wavelengths, when using a microplate reader. Filters offered higher performance because of greater light transmission and wider bandwidths; monochromators offered greater flexibility, no new filters had to be bought for each new assay.
However, researchers say that monochromators cannot perform many assays . Fluorescent protein assays like EGFP, mTomato, or CFP-YFP, do not perform well on monochromator-based microplate readers. The same holds true for FRET and BRET assays. A main reason is that wider bandwidths are needed for these assays and current monochromators have fixed or limited bandwidths only up to 30nm.
New LVF Monochromators™ Have Filter-like Performance
Realising the need for a more sensitive, broader bandwidth monochromator in a microplate reader, BMG LABTECH's German engineers created the CLARIOstar® multimode microplate reader with new innovative LVF Monochromators™ (Fig 1).
Consisting of linear variable filters separated by a linear variable dichroic mirror, LVF Monochromators™ filter light into definable wavelengths and bandwidths up to 100 nm wide.
Microscope to Microplate Reader - No Filters Needed
Researchers routinely try to adapt their fluorescent protein assay from a confocal microscope to a microplate format. Now with LVF Monochromators™ no filters are needed. Figure 2 shows an mTFP1-YFP fluorescent FRET response in HEK293 cells as measured on a confocal microscope and on the CLARIOstar®. This FRET assay requires teh measurement of two emission signals with bandwidths of 30nm and 45nm for the microscope , which were the starting points for the CLARIOstar®'s LVF Monochromators™. With further optimization, the same percent change is seen, making it an almost seamless transition to a higher throughput method without buying new filters.
1] Comley, J. Drug Discovery World. Fall 2007
2] Padilla-Parra S, et al. Biophys J. 2009 Oct; 97:2368-76.
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