Filters vs. Monochromators - 

Fig. 1: With adjustable bandwidths up to 100nm, new LVF Monochromators found in the CLARIOstar microplate reader have filter-like performance in fluorescent protein assays.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 [1]. 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).

Fig. 2: mTFP1-YFP tandem FRET assay in live HEK293 cells as measured on a confocal microscope [2] and on the CLARIOstar microplate reader. With the CLARIOstar's new LVF Monochromators, no new filters are needed.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.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 [2], 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.

References

1] Comley, J. Drug Discovery World.  Fall 2007

2] Padilla-Parra S, et al. Biophys J. 2009 Oct; 97[8]:2368-76.

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