If you are on the market for a new fluorescence plate reader, there are a few factors to take into account, as the performance of the instrument can significantly affect the quality of your research data.
Sensitivity
For quantification purposes, fluorescence plate readers generally offer greater sensitivity than absorbance readers. Nevertheless, a fluorescence microplate reader with better sensitivity will deliver data with a better statistic, less variability among replicates, and a larger delta (distance) between responding and not-responding samples. In addition, a better sensitivity will allow you to reduce the amount of reagents and/or samples used to achieve good quality data and consequently reduce costs.
Dynamic range
In fluorescence intensity detection, samples often cover a vast range of concentrations. Signals that have to be measured on a fluorescence plate reader may span over a wide range of signal intensities – from dim to very bright. Moreover, samples of enzymatic or cell based kinetic assays are often hard to predict in their signal intensity, as their maximum signal builds up over a lapse of time during the course of the kinetic.
In these cases, it may be difficult to acquire all signals in one measurement with one setting. Very bright samples may saturate the fluorescence detector of the microplate reader. Very dim samples may be undiscernible from the blanks.
Having a large dynamic range allows your fluorescence plate reader to acquire highly divergent samples in one run, avoiding waste of reagents and time caused by multiple trial-and-error measurements to find the correct dilution to fluorescence gain ratio. The Enhanced Dynamic Range feature on the CLARIOstar Plus and VANTAstar offers the largest possible dynamic range on the market (8 concentration decades), and makes it possible to automatically measure very bright and dim signals in the same measurement – no adjustment required.
Wavelength selection
A wavelength selection capability in fluorescence microplate readers is mandatory both for excitation and emission. This helps to reduce unspecific background or noise that is usually caused by light scatter or autofluorescence from both the sample and the microplate.
Filters or monochromators can be employed for this purpose. Filters are usually more sensitive, whereas monochromators offer more flexibility. An exception to this paradigm is the Linear Variable Filter (LVF) Monochromator system available on the CLARIOstar Plus and VANTAstar. LVF monochromators have filter-like performance and make the CLARIOstar Plus the most sensitive monochromator-based microplate reader on the market.
Additionally, the capability of detecting two emission channels simultaneously on a fluorescence plate reader is quite beneficial for FRET assays. This option halves measurement time and reduces data variability. Simultaneous Dual Emission (SDE) detection is available on the PHERAstar FSX and is an option on the LUMIstar Omega and FLUOstar Omega.
Compatible microplate formats
Commonly in life science research, basic fluorescence assays are measured in 96 well microplates. However, if you have multiple samples and/or wish to save precious reagents or time, 384 well and 1536 well formats can also be used. Just make sure that your fluorescence microplate reader of choice is also capable of reading the microplate format you plan on using.
Reagent injectors
When looking for a fluorescence plate reader, you should consider the nature of the assay you want to run. For enzymatic kinetics or real-time cell based responses, the use of reagent injectors can be beneficial. By manually pipetting reagents into the wells you can run the risk of losing important data of your reaction. Especially for fast responses, the event you are looking for may already be gone before you detect it. Our fluorescence plate readers equipped with reagent injectors can simultaneously inject and detect the signal of a well, and then move to the next one.
Environmental control
If your research requires long-time live cell based assays and you do not want to shuffle your microplate back and forth between fluorescence microplate reader and incubator, make sure that your reader of choice has the capability to control itsinternal gas environment.
The Omega series, the VANTAstar and the CLARIOstar Plus can be equipped withour Atmospheric Control Unit (ACU). The ACU provides the ideal environment for any application with living cells. The ACU independently regulates both O2 and CO2 gas levels within the microplate reader chamber. Combined with shaking and temperature incubation, the ACU provides a real “walk-away” solution for any cell-based assay from standard cell growth to hypoxic assays.
