The biological cycle of our existence it seems relatively simple: we are born, we live, we die. The end.
But when you examine existence at the cellular level, things get a little more interesting. You, me and all 108 billion or so A wise man those who have ever walked the Earth have all been our own constellation of about 30 trillion cells. Each of our bodies is a collective organism of living human cells and microbes working cooperatively to create what our minds consider “life.” However, a growing number of new studies have found that, at least for some cells, death is not the end. Instead, the beginning of something new and completely unexpected is possible.
A growing snowball of research into a new class of AI-engineered multicellular organisms known as “xenobots” are gaining scientific attention for their apparent autonomy. In September 2024, Peter Noble, PhD, a microbiologist at the University of Alabama at Birmingham, along with Alex Pozhitkov, PhD, a bioinformatics researcher at City of Hope Cancer Center, detailed this research on the website. conversation.
Xenobots are cells that form new roles beyond their original biological function—for example, using hair-like cilia for locomotion rather than transporting mucus. Because they seem to regroup into this new form and function, the authors argue that the xenobots form a kind of “third state” of life, where cells can reorganize after an organism dies to form something new. These forms probably wouldn’t materialize in nature, but the xenobots show that cells have a surprising ability to adapt to changes in their environment. Experiments with human cells or “anthropots” also exhibit this behavior.
“Taken together, these findings … challenge the idea that cells and organisms can only evolve in predetermined ways,” the authors write in conversation. “The third state suggests that [an organism’s] death can play a significant role in how life is transformed over time.”
The implications for these cellular robots, or biobots, are quite large – imagine personalized medicine created from your own tissues to avoid a dangerous immune response. But they also form a complicated picture of what a cell actually is. At least, that’s what evolutionary biologist and physician William Miller thinks. He co-authored the book 2023 Sensitive cellwhich explores the ideas found in the Cellular Basis of Conscience (CBC) theory suggesting that cells retain some kind of consciousness. Miller believes the xenobots are just another example of how we don’t give credit to the inherent cognitive — or even conscious — abilities of the cells that make up our bodies.
“The organism as a whole no longer responds as it did, but subsets of cells are active, making decisions and solving problems,” says Miller. “So this fundamentally reconstitutes the way we see the living framework … the fundamental unit of biological agency is the conscious cell.”
Consciousness is a notoriously slippery term, and one whose definition can change across fields of study, context, or even over time. Famously, the 17th century philosopher, mathematician, scientist, and smart guy René Descartes believed that only the human mind was conscious (which led to some inhumane experiments). Fortunately, science today recognizes different types of consciousness throughout the animal kingdom; but when it comes to life forms fundamentally different from us, human biases of what can be conscious or intelligent slowly creep in.
“We as humans have a very limited and finely honed ability to see the intelligence of medium-sized objects moving at medium speeds through three-dimensional space,” says Tufts University developmental and synthetic biologist Michael Levin, PhD, in a study. video exploring cellular intelligence. His lab has built xenobots and says that human beings don’t recognize intelligence when it’s “extremely small or extremely high.”
For Miller, the sentient cell concept is a fundamental change in biology, challenging some neo-Darwinian ideas such as “survival of the fittest”. Because cells must work together to be successful, a more accurate microbial expression might be “I serve myself best by serving others,” says Miller.
Putting the intelligent cell at the center of biology “sheds a whole new biological narrative, where genes don’t control, genes are tools. Where we understand why organisms choose to stick together in the trillions, to solve problems, [for] decision making, mutual support, partnerships, synergies, codependencies, collaboration – it’s not survival of the fittest,” says Miller.
Many scientists are not sold on this bold future for biology. A letter from 2024 published in the journal EMBO reports]describes the CBC theory as “a mere intellectual exercise without empirical evidence”, and the authors remain equally skeptical of claims of consciousness regarding xenobots or other “third state” organisms.
“It has been known for about 75 years or more that cells can be induced to grow abnormally when taken out of context and grown in vitro. This is nothing new,” University of California, Santa Cruz plant biologist Lincoln Taiz, PhD, and co-author of the letter, said in an email. “When a herbivorous insect secretes hormones into the plant’s leaves, causing the leaves to form galls [abnormal growths] that serve as homes for the insect, is this a ‘third state’ of life?” Taiz has also addressed what he describes as the “myths” surrounding plant consciousness and co-authored a review in 2019, entitled “Plants do not have and do not require consciousness”.
And for Wendy Ann Peer, PhD, a biologist at the University of Maryland who also served as a co-author of the dissenting CBC letter, the idea of cellular consciousness simply lacks the scientific rigor to be considered a theory. “With the scientific method, there has to be a control and a hypothesis that is clearly tested,” says Peer. “And the key to your hypothesis is that it must be falsifiable.”
When cells are taken out of context and no longer exchange information or signals from nearby cells, different genes can be expressed than what is normal, Peer says. Simply put, xenobots are an advanced version of “animal staples,” a well-known technique in developmental biology where cells retain their ability to differentiate into other cells.
While some experts say that cells are more than automatons that follow strict genetic orders, scientists still overwhelmingly define consciousness as something with a nervous system and a brain capable of providing a subjective point of view. However, despite this disagreement, both groups agree on at least one important point – understanding cells and exploring their many capabilities is a huge opportunity. Taiz compares the potential use of anthrobots in medicine to humans behaving like their own “gall-forming insects in plants” by altering the development of stem cells to create certain cellular behaviors.
Meanwhile, Miller agrees. “Levin’s work is a good example of trying to discern how to partner with cells to create living forms that help people,” he says. “We learn to do what cells do, and we’ll associate with them if we’re smart.”
Consciously or not, it seems that cells will undoubtedly play a leading role in the unfolding future of human health.
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