• We’re born, we live, and we die but new studies exploring the phenomenon of dead cells taking on new functions after death, also known as the “third state,” is complicating that picture.
• In a research review, two biologists explore the latest research in this growing field of xenobots and anthrobots that appear to live on after the original organism has died.
• In the future, these “third state” cells could deliver drugs without triggering an immune response and could help tackle the source of certain conditions, such as atherosclerosis and cystic fibrosis.

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In the world of biology, scientists are quickly exploring the ins and outs of a mysterious idea known as the “third state,” a somewhat spooky, awe-inspiring phenomenon when the cells of a dead organism can adopt new functions even after death.

In an article for The Conversation, University of Washington biologist Peter Nobel and Bioinformatics researcher Alex Pozhitkov from City of Hope cancer center in California detail how the exploration of xenobots and anthrobots have surprised scientists with their ability to survive beyond the life of the host organism. In July, the researchers published a comprehensive review in the journal Physiology of the mountain of studies in the last few years that show the potential these third-state biobots have for providing new and novel therapies.

“Taken together, these findings demonstrate the inherent plasticity of cellular systems and challenge the idea that cells and organisms can evolve only in predetermined ways,” the researchers wrote. “The third state suggests that organismal death may play a significant role in how life transforms over time.”

The authors focus on one particularly astounding study from Tufts University in Massachusetts, which extracted skin cells from deceased frog embryos and watched them reorganize into a new multicellular organism the paper called “xenobots.” Unlike some cells such as tumors or organoids that continually divide after death, these xenobots took on new behaviors beyond their biological roles. Studies have also found this ability in human lung cells, creating anthrobots capable of self-assembling and moving around.

There’s a litany of factors that influence exactly how these cells live on after death, including time elapsed since death, infection, trauma, and metabolic activity, along with other more mundane factors such as age, health, and sex. The running hypothesis as to why this happens still remains a mystery, but there is a leading theory.

“One hypothesis is that specialized channels and pumps embedded in the outer membranes of cells serve as intricate electrical circuits,” the authors wrote in their review of the available research. “These channels and pumps generate electrical signals that allow cells to communicate with each other and execute specific functions such as growth and movement, shaping the structure of the organism they form.”

But the real promise of these anthrobots is the possibility of them being farmed from living tissue while a patient is still alive. If scientists could engineer these anthrobots to deliver much-needed drugs, it’s unlikely that these cells would trigger an immune response. These bots could also alleviate the causes of conditions such as atherosclerosis and cystic fibrosis.

Luckily, this third state isn’t some immortal realm where cells live on into infinity. Instead, they usually perish around four to six weeks, so any medicines delivered by these bots wouldn’t inadvertently cause invasive cells to take hold, essentially killing the patient to cure the disease.

Scientists are really only just on the cusp of understanding this biological “third state,” but even these early results show that life and death isn’t quite as black and white as we once believed.