Organ On A Chip, Why Not?

22.07.2020 - Pirmin Fuchs
Organ on a chip
The organ on a chip (OOAC) is an emerging technology.
It refers to a chip in which fluid flows in tiny channels and cells are seeded alongside or in separate wells. The chip is a cross-technology innovation at the intersection of cell biology, biomaterial technology, engineering, and chemistry.
The chip behaves structurally and functionally like a human organ because it possesses the features of a live organ. It responds to different stimuli such as different drugs, microbes, and environmental factors in the same way as its human counterpart.
To mimic the actual biological organ or organ system, several cell types are used and the co-culture is seeded in several layers. The resulting system resembles the organ on a smaller scale. Each OOAC is made up of a transparent and flexible polymer, carrying hollow channels lined by live human cells. Additionally, physical microenvironment can be created by mechanical forces, e.g respiratory motions, gut movement etc.

Advantages of Organ on a Chip
During conventional drug development, most candidates that pass the pre-trial tests will be rejected during human trials.
Of the promising candidates, 30 % are found to be toxic and 60 % fail due to low, or no efficacy. Animals have been part of drug testing for decades and there have not been suitable alternatives. The use of animals gives rise to ethical issues and drugs may not behave in humans as in animals due to differences in biology.
A 2D culture has its limitations too as these cannot provide the same microenvironment as in human beings. The organ on a chip technology is solving this problem. These chips simulate the mechanics and biology of an organ hence eliminating the use of animals and cultures for drug development, enabling rapid development of drugs.
Another benefit is cost-effectiveness. Animals are expensive to keep, and human trials are high risk, daunting investments. By decreasing the cost of developing a drug, and increasing the success rate of each new product, the price tag of future medications and therapies could drop significantly.

One of the disadvantages of cell culture was the motionless nature of the cells. There were no movements like the original human organ.
As a result, an organ on a chip is designed to replicate the actual movements and actions of the human organ. For example, a heart on a chip - cells will replicate the pumping of the heart.
Similarly, the brain on a chip will have electrical activity, and in lungs on a chip - cells will behave like a lung.
Transport of the animals is a big concern, as various ethical guidelines and regulations need to be followed, but the OOAC looks to solve this problem. It is the size of a memory stick, so transportation becomes less challenging. However, the cultivation environment requires high maintenance. An optimal way of transporting these chips would be to use devices that mimic the in-vivo conditions, an example of such a device is the Cellbox.
One of the future possibilities of OOAC is to replicate and connect all organs to create a personalised organ on a chip. In this way, the exact effect of a drug or pathogen can be tested for individuals, thus improving precision medicine.

What Organs Are Available On OOAC?
The following organs have been developed in OOAC form;
• Heart on a chip
• Intestine on a chip
• Lung on a chip
• Brain on a chip
• Liver on a chip
• Multi-organ on a chip

Although "organ on a chip" is still in continuous improvement and expects a boom in its market in the coming years, this technology is still in continuous research for many of its limitations. Replicating the complete architecture of the human organs is challenging, and there needs to be standardisation of the techniques for comparability of data.

The Bottom Line

Organ on a chip is a promising alternative to animal trials and laboratory cultures. However promising the innovation seems, mimicking an entire body on a chip is many man-hours away and the possibility is endless.


References

1. Wu, Qirui, et al. "Organ-on-a-chip: recent breakthroughs and future prospects." BioMedical Engineering OnLine 19.1 (2020): 9.
2. Introduction to Organs-on-a-Chip- https://wyss.harvard.edu/media-post/introduction-to-organs-on-a-chip/#:~:text=Each%20individual%20organ%2Don%2Dchip,applied%20to%20mimic%20the%20physical
3. About Tissue Chip- https://ncats.nih.gov/tissuechip/about
4. Organs-on-a-Chip for Faster Drug Development- https://www.scientificamerican.com/article/organs-on-a-chip/
5. Human Organs-on-Chips- https://wyss.harvard.edu/technology/human-organs-on-chips/
6. Cellbox- https://cellbox-solutions.com/
7. Organs on Chip 2017- https://www.elveflow.com/microfluidic-reviews/organs-on-chip-3d-cell-culture/organs-chip-review/