Medical research traditionally relies on non-human animal models, especially when verifying the safety of new drugs for human use. However, animal models often provide inaccurate approximations, and experimenting on large numbers of live animals involves significant time and resource constraints. Additionally, the use of animals for medical research is ethically controversial since it requires millions of animals globally each year to be bred in captivity, exploited, then ultimately killed. Finding alternatives to animal testing is an important priority. 

This is where organ on a chip (OOAC) technology comes in. OOAC allows researchers to simulate the physiological environment of human organs by growing human cells on small devices (“chips”) containing microfluid channels. These channels allow cells to exchange chemical signals in order to communicate, just like in real human bodies. The microfluid environment even allows researchers to simulate the mechanical pressures that organs in the human body face, including blood, lung, and bone pressure. Sensors within the OOAC record the reaction of the cells to drugs or other materials which the researchers want to test.

Researchers have already created OOAC models of several human organs, including the liver, lungs, kidney, and heart. In recent decades, OOAC models have advanced to include multiple organs on one chip. Having multiple organs on one chip allows researchers to study interactions between cells of different organs rather than only between cells of the same organ. The ultimate goal of OOAC is to get all human organs modeled together, thus creating a “human on a chip.” However, several barriers stand in the way. One barrier is sourcing stem cells for growth on the chip. Stem cells can be induced to mature into one or more specialized cell types, making them ideal for growing different organs. The problem is that stem cells from human embryos are generally more useful than stem cells from adult human bone marrow, but these are also more difficult to source ethically. Another challenge is trying to prevent the material that the chip is made from, commonly polydimethylsiloxane (PDMS), from having effects on the cells that would not be present in the human body. A third barrier comes from the fact that 3-D chips do a better job of simulating real human organs by arranging cells on structured scaffolds, but 2-D chips are more common because they are less complex and therefore easier to build. 

These barriers make manufacturing OOAC and using them in studies costly and difficult for the time being. As researchers make progress on improving the material construction of OOAC and making them easier to work with, the hope is that OOAC technology can advance far enough to complement and eventually replace invasive tests on non-human animals. Advocates can spread the word about OOAC technology to dispel the myth that animal testing is the only possible way to advance human health and safety. Advocates studying or working at research universities can push administrators and professors to include education on OOAC technology in classroom curricula. They can also encourage their university to sponsor more research and discussions on OOAC technology, and to incorporate OOAC methods wherever possible in their current research. Finally, advocates can urge their local politicians to sponsor bills that push for more urgent legislative demands to phase out animal testing.