We humans have been a cruel species. How many mice, primates and other animals have been tortured so that we could have our drugs! Worse, testing new drugs on animals was never a sound idea, in any case. More than 90 per cent of the drugs that enter human trials fail despite positive results in preclinical animal tests.

The push for ‘cruelty-free’ medicines saw groups like Cruelty Free International, Animal Defenders International and People for Ethical Treatment of Animals come into being.

Then came computing power and a new branch of science — computational biology. So, today, we have devices that mimic a human organ.

‘Organs-on-a-chip’ are very likely to replace lab animals, as they are proving to be better proxies for human organs. A lung-on-a-chip mimics a human lung better.

As Jarrod Bailey, senior research scientist at Cruelty Free International, explains: “Computational methods have been shown to be more reproducible and human-predictive than animal tests, and various cell-based assays have shown superior human relevance.”

How does an organ chip work?

Boston-based Wyss Institute, a pioneer in this technology, explains it thus: An organ chip is composed of a clear, flexible polymer about the size of a computer memory stick. It contains hollow microfluidic channels lined by living human organ-specific cells. This is interfaced with a human blood vessel liner (endothelial) cell vasculature. Mechanical forces can be applied to mimic the physical microenvironment of living organisms, including breathing motions in lung and deformations in the intestine.

Sometimes, two organs-on-chips can be connected, so that scientists can observe them work together.

One of the more recent Indian works in this area is that of Jyotsana Priyadarshani, a research scholar at IIT Kharagpur. She has published a paper about designing a tumour-on-a-chip platform, by replicating the mechanism of angiogenesis, or the emergence of new blood vessels from existing ones. The platform captures the movement of cells produced by tumours and the growth of micro-blood vessels. The idea is to find out how a tumour interacts with its immediate neighbourhood.

Such bio-mimetic devices enable cost-effective development of drugs, their delivery mechanism and cell biology research, compared with animal testing.

But wait! This is not a mature technology yet. Experts such as Addicam Jagannadha Rao of the Indian Institute of Science, Bengaluru, and Amit Misra of the Central Drug Research Institute (CDRI), Lucknow, have expressed reservations about the effectiveness in areas like toxicity studies.

However, organs-on-a-chip ought not to be viewed in isolation. For areas like toxicity studies, artificial intelligence comes into play. “With computing power now more accessible and far more affordable,” writes Thomas Hartung of the Centre for Alternatives to Animal Testing, John Hopkins University, in The Scientist , “AI is the solution to many real-world problems, such as limiting the need for animals in biological research.”