Cell-Free Assays in Environmental Toxicology

Predictive toxicology requires in vitro tests that can help prioritize, screen, and evaluate a large number of chemicals (i.e., thousands) in a relatively short period of time (days to weeks). Cell-free assays represent a relatively simple in vitro tool that can characterize the interaction between test chemicals and biochemical targets, and are increasingly being used to study a range of fish and wildlife, and also screen single chemicals as well as complex mixtures of environmental samples. The purpose of this chapter is to describe cell-free assays, and propose them as a species agnostic, in vitro toxicity-testing tool of potential relevance to ecological risk assessment. In doing so, the chapter aims to show that cell-free tests are an attractive tool that can be used in predictive ecotoxicology especially considering the limited availability of test organisms (particularly species that are at-risk, difficult to maintain in captivity, etc.), lack of proven cell-based tools (e.g., cell cultures and cell lines), societal concerns over animal testing, sheer number of ecological species to study, and vast inter-species differences.