Novel fluorescent technology platform for high throughput cytotoxicity andproliferation assays

We have developed a novel fluorescent Oxygen BioSensor technology platform adaptable to many applications in the area of drug discovery and developmen t, particularly cell-based assays. This biosensor technology requires no ad ditional reagents or incubations, and affords continuous real-time readout of dissolved oxygen concentrations. Since the level of oxygen dissolved in an assay's medium correlates to the number and viability of the cells in th e medium, this technology is ideally suited for monitoring cell viability, proliferation, or death. The technology is particularly well suited to inve stigating cells' kinetic responses to proliferative or toxic stimuli, such as drugs. When incorporated into a 96- or 384-well microplate format, it is compatible with standard laboratory automation systems. Here we present da ta illustrating the application of the Oxygen BioSensor technology for rapi d, homogeneous detection and evaluation of metabolic activity of a variety of eukaryotic and prokaryotic cells, including mammalian cells, insect cell s, yeast, and bacteria. In the absence of toxic substances, we find a good correlation between cell number and signal over a wide range of cell concen trations and growth times. To evaluate the usefulness of the Oxygen BioSensor for cytotoxicity assays, we have performed a series of experiments using a range of toxic agents an d cell types, including both bacteria and mammalian cell lines. In a side-b y-side comparison to standard MTT assays using HL60 cells, comparable IC50 values were found with the Oxygen BioSensor for five different toxins or dr ugs. This assay method does not have the need for additional reagents, hand ling steps, or incubation periods required by the MTT assays.