Image-based screening is essentially automated fluorescence microscopy performed on large numbers of samples, commonly of adherent cells in wells of micro plates. Use of a fluorescent DNA probe allows counterstaining and therefore location of individual cells, segmentation of their nuclei and total cell enumeration. A cell-permeant counterstain permits choice of either live- or fixed-cell endpoint assay and simple transfer between the two.
A fluorescent viability probe can be utilized in live-cell assays to help establish levels of cellular toxicity, apoptosis induction and cell health.
Non-adherent cells or microtissues or motile organisms may require immobilisation to permit reliable and high-performance imaging of structures and changes.