It should soon be easier to tell a chemical’s toxicity without killing animals
THE number of chemicals that might come into contact with a human being is staggering. The European Chemical Agency (ECHA) recognises over 130,000 molecules. Its American counterpart recognises 85,000. Testing all of these for toxicity is well-nigh impossible. Animal testing, in particular, is controversial, slow, costly and often cruel. Nor is it reliable. Its results are often irreproducible.
Things would be better if there were some way to predict the likely toxicity of a substance before animals get involved. That would permit the riskiest-looking to be prioritised. To this end, toxicologists like Thomas Hartung of Johns Hopkins University, in Baltimore, have been trying for years to find objective links between a chemical’s molecular structure and its biological activity. And now Dr Hartung thinks he has one. It relies, as do so many advances these days, on machine learning.
A way to link molecular structure and biological activity does already exist. It is...