Less than 10 GFP positive cells - (May/26/2013 )
I harvested the tissues (such as pancreas, liver and spleen) in order to detect if there is any GFP+ cells
Is it possible to analyse/sort the tissues samples using FACS to quantify the number of GFP+ cells which might be less than 10 cells!?!
Yes, this is commonly done. Flow cytometers are more sensitive to GFP signal than the naked eye so they can detect GFP positive cells when you do not see them in the fluorescence microscope. For certain experiments on cells with low transfection efficiencies, I will sort out the GFP positive cells by FACS and use those in my next assay.
just make sure you have a negative control, no GFP expressing cells. If your wanting to look at cells from transgenic mice, get a sample from a mouse that is not supposed to express GFP. If this is from transfected cells, set aside a aliquot of cells that were not transfected. These controls are vital to determining from where your GFP signal is coming. All cells have some level of background fluorescence and this differs between cell lines and cell types... so make sure the cell types are the same.
Thank you for the suggestion.
Have a nice day