In vitro assays to screen and prioritize toxicants

The Simpson lab will use the Chinese hamster ovary (CHO) cell chronic cytotoxicity assay, developed by Dr. Michael Plewa and Dr. Suzan Wagner, to screen and prioritize toxicants individually, as mixtures, and even as extracts from water. This assay measures the decrease in cell density as a function of contaminant concentration over a 72 h period, which is a chronic exposure because the cells are incubated over 3 – 4 generations. The endpoint of interest for this assay is the LC50 which is the concentration of a toxicant that elicits a 50 % reduction in cellular density.

The benefits of using the CHO cell chronic cytotoxicity assay are numerous: 1) cytotoxicity as a general metric of toxicity captures many modes of toxicity, 2) the assay uses mammalian cells, 3) the cells express cell contact inhibition and are thus not neoplastic, and 4) > 100 disinfection byproducts (DBPs) of concern in drinking water have been tested using this assay. In Spring of 2023, Dr. Simpson learned this assay as a visiting scholar under Professor April Gu and her researchers in the civil and environmental engineering department at Cornell University. Professor Simpson plans to use this assay as a screening tool for the toxicants he discovers and measures in food and water within the lab.