In vitro toxicology

In vitro assays for xenobiotic toxicity are recently carefully considered by key government agencies (e.g., EPA; NIEHS/NTP; FDA), to better assess human risks.

Major findings from the analysis of this ToxCast_STM dataset published in 2020 include: (1) 19% of 1065 chemicals yielded a prediction of developmental toxicity, (2) assay performance reached 79%–82% accuracy with high specificity (> 84%) but modest sensitivity (< 67%) when compared with in vivo animal models of human prenatal developmental toxicity, (3) sensitivity improved as more stringent weights of evidence requirements were applied to the animal studies, and (4) statistical analysis of the most potent chemical hits on specific biochemical targets in ToxCast revealed positive and negative associations with the STM response, providing insights into the mechanistic underpinnings of the targeted endpoint and its biological domain.

ATP assay has the main advantage of providing results quickly (within 15 minutes) and only requires fewer sample cells.

Neutral red, a weak cationic dye penetrates cellular membranes by non-diffusion and accumulates intercellularly in lysosomes.

These assays are quite beneficial as they are quite simple and provide a very accessible testing environment for monitoring chemicals in the culture medium as well as in the cell.

However the disadvantage of using these simple static well plate assays is that, they cannot represent the cellular interactions and physiologic fluid flow conditions taking place inside the body.

[8] To improve the biological difficulties arising from the use of different culture in vitro conditions, the traditional models used in flasks or micro-well plates has to be modified.

With parallel development in micro-technologies and tissue engineering, these problems are solved using new pertinent tools called "micro-fluidic biochips".