Using the same biological endpoints, the teams human lung organoids showed a similar biological response, which validates them as tools for predicting nanomaterial driven responses in lung tissue.

The human organoids enabled better understanding of interactions of nanomaterials with the model tissue, but at the cellular level.

Graphene oxide (GO), a flat, thin and flexible form of carbon nanomaterial, was found to be momentarily trapped out of harms way in a substance produced by the respiratory system called secretory mucin.

In contrast, MWCNT induced a more persistent interaction with the alveolar cells, with more limited mucin secretion and leading to the growth of fibrous tissue.

In a further development, Dr Issa and Vranic based at the Universitys Centre for Nanotechnology in Medicine are now developing and studying a ground-breaking human lung organoid that also contains an integrated immune cell component.

Dr Vranic said: With further validation, prolonged exposure, and the incorporation of an immune component, human lung organoids could greatly reduce the need for animals used in nanotoxicology research.

Developed to encourage humane animal research, the 3Rs of replacement, reduction and refinement are now embedded in UK law and in many other countries.

Public attitudes consistently show that support for animal research is conditional on the 3Rs being put into practice.

Professor Kostas Kostarelos, Chair of Nanomedicine at the University said: Current 2D testing of nanomaterials using two-dimensional cell culture models provide some understanding of cellular effects, but they are so simplistic as it can only partially depict the complex way cells communicate with each other.

It certainly does not represent the complexity of the human pulmonary epithelium and may misrepresent the toxic potential of nanomaterials, for better or for worse.

Though animals will still be needed in research for the foreseeable future, 3D organoids nevertheless are an exciting prospect in our research field and in research more generally as a human equivalent and animal alternative.

Read more:
Scientists grow human mini-lungs as animal alternative for nanomaterial safety testing - The University of Manchester