GreenScreen HC and GreenScreen GC
Microplate based GreenScreen HC (and GreenScreen GC) assays, are designed to be compatible with standard off-the-shelf laboratory automation. They require the use of a microplate plate reader capable of performing both fluorescence and absorbance measurements on 96-well microplates. Following in-house evaluations, Gentronix recommends the following plate readers for use with GreenScreen HC:
The GreenScreen assays each use two strains, one of which does not express GFP, to allow the software to correct for the otherwise interfering effect of autofluorescent compounds. In a minority of cases, for analytes that are intensely autofluorescent at GFP wavelengths, a method of correction using fluorescence polarisation can be employed. This protocol exploits the high fluorescence anisotropy of the GFP molecule compared to other smaller autofluorescent species such as the test compound. For this reason it is preferable, though not essential, that the plate reader used for GreenScreen assays is also capable of performing fluorescence polarisation readings.
Cellular fluorescence is measured using standard factory fitted filters normally used for the measurement of fluorescein, a close spectroscopic mimic of GFP - typically excitation at 485 nm and emission at 535 nm. Absorbance is measured at 600 to 620 nm.
GreenScreen HC S9
The GreenScreen HC S9 assay utilises a flow cytometer for data collection. It is more convenient to process samples in a flow cytometer that has the facility to sample directly from 96 well microplates, else samples can be transferred to microtubes. GreenScreen HC S9 has been installed on a number of flow cytotmeters including:
BlueScreen HC
The BlueScreen HC assay uses flash luminescence to assess the expression of Gaussia luciferase. A microplate reader is required which has facility to read luminescence, fluorescence and optical absorbance. The microplate reader also requires facility to inject small quantities of reagent solutions (coelenterazine).
Following in-house evaluations thus far, Gentronix recommends the following plate readers for use with BlueScreen HC:
To discuss the instrument requirements for all Gentronix assays please contact Gentronix.