Recently, the media has been abuzz about cerebral organoids, which can produce brain-waves that resemble that of a human infant’s. Before delving into this hot topic, let’s first address a few questions: What are organoids? How are they playing a role in the advancement of stem cell research? What concerns have arisen about organoids? (For example, if organoids are capable of experiencing consciousness and pain, would it be unethical for scientists to carry out experiments on them?)
Organoids are three-dimensional cell cultures, which resemble miniature “organs.” Unlike a bacteria culture, which is a large group of single-celled organisms, scientists culture a organoid in a way such that the stem cells can differentiate and self-organize into a functional unit with specialized cell regions. Depending on the organoid they wish to create (for example, a liver, intestine, lung, or brain), researchers will create an environmental condition that is conducive to that organoid’s growth.
These miniature organ-like systems (some less than the width of hair!) have provided researchers a way to study biological processes and served as drug models. By studying organoids, researchers have gained a detailed insight into the formation and growth of organs. Researchers have also cultured organoids to observe how effective different drugs are on human tissues. As of now, scientists have been resorting to animal models and testing for their research. However, organoids provide a more attractive alternative. If researchers can culture organoids from human cells, they will no longer need to generalize the data gathered from other animals to humans and reduce the number of animals harmed.
While organoids open up many possibilities for research advancement, the discovery that cerebral organoids can generate brain waves has raised some ethical concerns. In 2016, Priscilla Negraes, a project scientist at the University of California San Diego, “listened” to brain organoids using 64 electrodes for each organoid. The neurons would cause the electrodes to light up, and over the week, she observed that the neurons in each of the organoids would “start firing in a synchronized burst,” much like human brain waves. Further study of the brain organoids reveal a pattern very similar to the brain activity of a premature baby brain.
This has led scientists to consider questions like how ethical it is to introduce pain receptor cells to organoids, record organoid memory (if possible), or conduct research of organoids that can experience emotions, such as distress. In addition, this has led researchers to contemplate the extent to which organoids accurately resemble human organs, which brings up another question about the limitations of organoid research. Since organoid research is still in its initial phase, these concerns have yet to be completely fleshed out and answered.
“Organoids: A New Window into Disease, Development and Discovery.” Harvard Stem Cell Institute (HSCI), Havard, 7 Nov. 2017, https://hsci.harvard.edu/organoids.
Zimmer, Carl. “Organoids Are Not Brains. How Are They Making Brain Waves?” The New York Times, The New York Times, 29 Aug. 2019, https://www.nytimes.com/2019/08/29/science/organoids-brain-alysson-muotri.html.