SCIENCE | CELL BIOLOGY | MEDICAL DISCOVERIES
For centuries, scientists have generally understood life and death as two distinct biological conditions. An organism is either alive, with its systems functioning together, or dead, when those essential functions have irreversibly stopped.
But a fascinating area of research is challenging how we think about what happens to individual cells after an organism dies.
Scientists have described a phenomenon they call a “third state” — a condition in which certain cells can survive the death of the organism they came from and, under carefully controlled laboratory conditions, reorganize into entirely new biological structures.
Even more remarkably, some of these structures can perform functions that the original cells never carried out in their natural environment.
The findings raise intriguing questions about cellular survival, biological organization, and the possibilities of regenerative medicine.
But there is an important distinction.
This research does not demonstrate life after death, the survival of human consciousness, or the resurrection of deceased organisms.
Instead, it reveals something scientifically extraordinary: the death of an organism does not necessarily mean that every cell within it immediately loses the ability to function.
What Exactly Is the Mysterious “Third State”?
The term “third state” gained widespread attention following a scientific perspective published in September 2024 in the journal Physiology.
Researchers Peter Noble and Alex Pozhitkov examined evidence suggesting that cells from deceased organisms can sometimes reorganize and develop new functions when placed in suitable environments.
Traditionally, biological death is understood at the level of the entire organism.
For example, when a person dies, the coordinated functions necessary to sustain the body have irreversibly ceased.
However, different tissues and cells do not all die simultaneously.
Some cells may remain viable for a period after the organism’s death, depending on environmental conditions, oxygen availability, temperature, and cell type.
The researchers argued that certain experiments reveal a particularly interesting phenomenon.
Cells can sometimes do more than merely survive.
They can organize themselves into new multicellular structures that behave differently from the tissues they originally formed.
This capacity is what inspired the description of a possible third biological state.
The Discovery That Started With Frog Cells
One of the most remarkable examples involves tiny biological structures known as xenobots.
Xenobots were developed using cells from embryos of the African clawed frog, scientifically known as Xenopus laevis.
Researchers discovered that when certain frog cells were removed from their original developmental environment and arranged under laboratory conditions, they could form small, functional multicellular structures.
These structures were not ordinary frogs.
They did not resemble conventional organs.
And they did not behave exactly like the tissues from which they originated.
Instead, the cells organized into tiny living assemblies capable of moving through their surroundings.
Some xenobots could even gather loose cells and help form additional structures under specific experimental conditions.
This phenomenon attracted enormous scientific attention because it demonstrated how cells can express capabilities beyond their usual roles in an organism.
Why xenobots are so unusual
The cells used to create xenobots contain the same genetic information they had in the original frog embryo.
Yet their behavior changes when they are placed into a new physical and biological environment.
This suggests that genes alone do not determine every aspect of a cell’s behavior.
Interactions between cells, their environment, and their physical arrangement can also influence what they do.
However, xenobots were created from living embryonic cells. They are not themselves proof that cells collected from dead frogs can automatically regenerate into new organisms.
That distinction is essential to understanding the research accurately.
Then Scientists Created Something Even More Surprising: Anthrobots
While xenobots demonstrated remarkable behavior in frog cells, another line of research explored whether human cells could form similar structures.
Scientists at Tufts University and Harvard University’s Wyss Institute developed tiny multicellular structures called anthrobots.
Unlike xenobots, anthrobots were created from adult human tracheal cells — cells that normally line parts of the respiratory system.
These cells have microscopic hair-like structures called cilia.
In the human body, cilia help move mucus and trapped particles through the airways.
But when the cells were grown under particular laboratory conditions, something unexpected happened.
They assembled into tiny spherical structures, with some of their cilia facing outward.
The coordinated movement of these cilia allowed certain anthrobots to move across laboratory surfaces.
The structures displayed different movement patterns, including circular and relatively straight trajectories.
Researchers were fascinated.
Cells that normally help keep human airways clear had formed tiny mobile biological assemblies.
And the most intriguing discovery was still to come.
The Tiny Human Cell Structures That Helped Repair Damaged Tissue
Researchers investigated how anthrobots interacted with other cells in a laboratory environment.
In one experiment, they created a scratch-like gap in a layer of cultured human nerve cells.
They then placed clusters of anthrobots near the damaged area.
The researchers observed that nerve cells grew across the gap beneath the anthrobot clusters.
This suggested that anthrobots might influence cellular repair under certain experimental conditions.
It was an exciting finding.
However, the experiment was conducted in cultured cells, not in a living patient.
Scientists have not demonstrated that anthrobots can repair damaged human spinal cords, cure neurological diseases, or regenerate organs.
Nevertheless, the results offer an intriguing starting point for future research into cellular organization and tissue repair.
How Can Cells Continue Living After the Body Dies?
The answer begins with understanding that an organism is made of many different kinds of cells.
When the organism dies, the processes that support those cells begin to fail.
Blood circulation stops, oxygen delivery ceases, and tissues gradually lose their ability to maintain normal function.
But the speed of cellular deterioration varies.
Some cells are extremely sensitive to oxygen deprivation.
Others can survive longer under favorable conditions.
For example, researchers have successfully recovered viable cells from tissues collected after an organism’s death.
This is one reason certain tissues and organs can be used in transplantation or scientific research after death, provided strict medical and preservation requirements are met.
The survival of individual cells does not mean the organism remains alive.
Rather, it demonstrates that biological death occurs through a complex series of processes rather than every cell stopping at precisely the same instant.
What Makes This Different From Ordinary Cell Survival?
The remarkable aspect of the proposed third state is not simply that cells can remain alive after the organism dies.
Scientists have known for decades that certain cells can survive outside the body.
The more unusual observation is that cells can sometimes reorganize and acquire new collective behaviors.
Consider the difference between a brick and a building.
A brick removed from a demolished house remains a brick.
But if those bricks are rearranged, they can become part of a completely different structure.
Cells are far more complex than bricks, but the analogy helps explain the concept.
Under certain conditions, cells removed from their usual biological environment may establish new relationships with neighboring cells.
Those interactions can produce behaviors that were not present in the original tissue.
This is an example of emergent behavior — when interactions among individual components produce properties at a larger organizational level.
Researchers are exploring how far this biological flexibility extends.
Could This Discovery Transform Medicine?
The potential medical applications are among the most exciting aspects of the research.
If scientists can reliably guide cells to assemble into useful biological structures, they may eventually develop new tools for treating disease and repairing damaged tissues.
Several possibilities are being investigated.
Repairing damaged tissue
Anthrobots have already demonstrated an ability to encourage nerve-cell growth across small gaps in laboratory cultures.
Future research could investigate whether similar structures might help repair other types of damaged tissue.
However, this remains an experimental possibility, not an established medical treatment.
Delivering medication to specific locations
Scientists envision a future in which tiny biological structures made from a patient’s own cells might transport medications to targeted areas.
Such an approach could potentially reduce unwanted effects on surrounding tissues.
The concept remains speculative and requires extensive testing.
Clearing harmful material from the body
Researchers have also discussed whether engineered biological structures could eventually help remove unwanted material, such as certain deposits in blood vessels.
This application has not been demonstrated as a safe or effective treatment in humans.
Developing personalized treatments
Because anthrobots can be created from human cells without genetic modification, researchers are interested in the possibility of using cells obtained from individual patients.
This could potentially reduce some immune compatibility problems.
Still, many questions about safety, control, manufacturing, and clinical effectiveness must be answered first.
Tufts Now
Does the Third State Mean Humans Could Come Back From the Dead?
This is perhaps the most important question raised by the dramatic headlines surrounding the discovery.
And the scientific answer is clear.
No. The research does not show that a deceased human being can return to life.
The survival of certain cells is fundamentally different from the survival of an entire person.
Human consciousness depends on extraordinarily complex and coordinated brain activity.
The experiments involving xenobots and anthrobots have not demonstrated that memories, personal identity, awareness, or consciousness survive death.
They also do not provide evidence for an afterlife.
The term “third state” describes an intriguing way of thinking about cellular organization, not a newly proven state of human existence between being alive and dead.
It is a scientific proposal concerning the remarkable flexibility of living cells.
Why Scientists Are Still Asking Questions
Although the findings are fascinating, researchers still have much to learn.
For example, why do certain cells form new structures while others do not?
How much of their behavior is determined by genetic information?
How much depends on their surroundings?
Could scientists control the development and behavior of these structures with enough precision to make them medically useful?
And what safeguards would be needed before introducing them into living patients?
These questions remain unanswered.
Scientists must also investigate how long such structures can survive, what causes them to stop functioning, and whether their behavior remains predictable over time.
According to Tufts University, anthrobots created in the laboratory survive only for a limited period under specific conditions and eventually break down. They do not reproduce in the manner observed in some xenobot experiments.
Tufts Now
A Discovery That Challenges Our Understanding of Cells
For generations, biology has taught us that cells work together to form tissues, organs, and living organisms.
The research behind the proposed third state adds another dimension to that understanding.
It suggests that some cells possess a surprising capacity to reorganize when removed from their original biological context.
They may form new structures.
They may move in unexpected ways.
And under carefully controlled conditions, they may perform functions different from those they carried out inside the original organism.
The implications could eventually reach fields such as regenerative medicine, tissue engineering, and personalized therapies.
But those possibilities are still being explored.
The Most Extraordinary Part of the Discovery
Perhaps the most remarkable lesson is that biology is far more flexible than scientists once assumed.
Cells are not merely passive building blocks.
They respond to signals, communicate with neighboring cells, and can sometimes organize themselves into complex structures.
The research discussed in the 2024 Physiology review challenges scientists to think more deeply about the relationship between individual cells and the organisms they form.
It also reminds us that scientific discoveries do not always fit neatly into familiar categories.
The proposed “third state” does not mean that death has been defeated. It means that some living cells may have capabilities we are only beginning to understand.
And if researchers can learn how to guide those capabilities safely, they may one day open new possibilities for medical treatment.
For now, the discovery remains a fascinating example of how much there is still to learn about life at its most fundamental level.
Scientific Sources
- Physiology (2024) — Unraveling the Enigma of Organismal Death: Insights, Implications, and Unexplored Frontiers.
American Physiological Society
- Tufts University — Scientists Build Tiny Biological Robots from Human Cells.
Tufts Now
- American Society for Biochemistry and Molecular Biology — Biobots Arise From the Cells of Dead Organisms.
asbmb.org
Editorial note: The scientific review was published online in April 2024 and appeared in the September 2024 issue of Physiology. The “third state” is a proposed biological concept, not proof of consciousness or life after death. Images are illustrative.
Did you know that certain cells can survive after the organism they came from has died? What do you think this research could mean for the future of medicine? Share your thoughts in the comments. 🔬
