In a groundbreaking development at the University of Minnesota, scientists have engineered a synthetic cell dubbed the SpudCell, which exhibits many behaviors characteristic of living cells. This synthetic construct can consume nutrients, grow, compete, divide, and replicate-completing a full cellular life cycle, according to its creators. The announcement of the SpudCell earlier in July 2026 generated considerable excitement and debate within the scientific community, with many questioning whether this achievement constitutes the creation of life itself. However, closer examination reveals that despite its similarities to natural cells, the SpudCell falls short of true life, mainly because it depends heavily on external support and cannot sustain its life cycle beyond a few generations.
The SpudCell's design includes many features typical of living cells. It has a lipid membrane that encloses its contents and a small set of genetic material, or genome. Remarkably, the entire cell is assembled from nonliving chemical components, marking a significant step forward in synthetic biology. Nevertheless, its capabilities remain limited. While it can perform basic cellular functions such as growth and division, it requires continuous supplies of ribosomes, nutrients, and lipids from outside sources to maintain these processes. This external dependency highlights a fundamental difference between the SpudCell and truly living organisms.
A crucial factor in understanding this limitation lies in the role of the ribosome, a complex molecular machine central to all living cells. Michael Jewett, a bioengineer at Stanford University not involved with the SpudCell project, describes the ribosome as the cell's "chef," responsible for translating genetic instructions into proteins. These proteins, long chains of amino acids, execute nearly all the functions necessary for a cell's survival and reproduction. If DNA is the cookbook and RNA the recipe card, the ribosome is the chef preparing the dish. Without ribosomes, a cell cannot produce the proteins it needs to function and replicate.
The SpudCell's genome includes instructions for eating, growing, copying its genetic material, and dividing, but it does not contain the genes necessary to produce ribosomes. Instead, the SpudCell borrows ribosomes from the bacterium Escherichia coli. Researchers supply these ribosomes, along with lipids and nutrients, via tiny droplets called liposomes. This borrowing allows the SpudCell to sustain protein production temporarily, enabling it to complete several rounds of division.
However, this borrowed machinery is not a permanent solution. After about five generations, the SpudCell's borrowed ribosomes degrade, and the cells' vitality diminishes. Aaron Engelhart, a geneticist and cell biologist at the University of Minnesota who worked on the project, notes that after these divisions, the SpudCells begin "limping along," unable to maintain the same robust behavior seen at the start. The cells fail to undergo successive rounds of division consistently, signaling a breakdown in their synthetic life cycle.
Why exactly the SpudCells falter after a few generations remains an open question. Jewett suggests that dilution may play a role: as the cells grow and divide, the ribosomes-borrowed from outside-may become too sparse to sustain ongoing protein synthesis. In other words, without the ability to make their own ribosomes, the cells gradually lose the molecular machinery necessary to function.
Another challenge concerns the inheritance of genetic material. Unlike natural cells, which typically have their entire genome contained in a single DNA molecule, the SpudCell's genome is fragmented across several separate DNA pieces. This fragmentation means that when the SpudCell divides, some daughter cells may not inherit a complete set of genetic instructions. According to the team's findings, after five rounds of division, only about 30 percent of the cells retain a full genome. This incomplete inheritance likely contributes to the cells' eventual decline and inability to sustain replication indefinitely.
The structural organization of the SpudCell also differs significantly from natural cells, which may further explain these problems. Engelhart explains that living cells divide through highly coordinated and complex processes that ensure orderly distribution of cellular components. In contrast, the SpudCell's division is a simpler, more mechanical process: proteins accumulate at the membrane until the stress causes the membrane to split into two. This less precise method means that internal components, including DNA fragments and ribosomes, may be distributed unevenly or randomly between daughter cells.
Inside living cells, the interior is densely packed yet highly organized, allowing efficient interactions among molecules essential for life. Replicating this intricate organization is a major challenge for synthetic biology. The SpudCell's lack of such internal order means that the distribution of molecules during division can be haphazard, undermining the stability and functionality of daughter cells.
A significant limitation of the SpudCell is its inability to produce ribosomes internally, as it lacks the necessary genes. Engelhart notes that future research aims to include these ribosome-producing genes within synthetic cells, but doing so presents a formidable challenge. Ribosome assembly is a highly complex process involving the synthesis and precise assembly of dozens of proteins and RNA strands. Successfully engineering a cell to build ribosomes from scratch would represent a major milestone in synthetic biology and could pave the way toward truly self-sustaining synthetic life.
Despite these limitations, the SpudCell may still have valuable applications even if it is not fully alive in the traditional sense. Jewett points out that many biotechnological uses, such as targeted drug delivery or diagnostic testing, do not require cells capable of indefinite self-replication. For example, his own lab has developed a cell-free system embedded with genetic programs that change color in response to contaminants in water. This system only needs to function once to deliver its intended effect, demonstrating that full cellular autonomy is not always necessary.
From an engineering perspective, leveraging biological processes without replicating every aspect of living cells can be an effective and practical approach. "You don't actually need a synthetic cell," Jewett explains, "you just need to be able to capture or harness the biological processes of living organisms." This outlook suggests that synthetic biology can create tailored systems optimized for specific functions without necessarily recreating life in its entirety.
While the SpudCell is not yet a fully self-replicating entity, its creation underscores the progress and potential in building cells from the ground up. Jewett emphasizes that this line of research can deepen our understanding of life itself by revealing what components and processes are essential for cellular function. Constructing synthetic cells offers a unique window into the fundamental nature of biology, allowing scientists to test hypotheses about what makes a cell truly alive.
In summary, the SpudCell is a remarkable synthetic construct that mimics many behaviors of living cells but remains dependent on external ribosomes and lacks the internal organization and genetic completeness to sustain indefinite replication. Its limitations highlight the complexity of life and the challenges faced in constructing synthetic life from nonliving components. Yet, the project represents a significant step forward in synthetic biology, providing new tools for research and potential applications in medicine and environmental monitoring.
As the field advances, integrating ribosome production and improving genetic inheritance mechanisms may bring synthetic cells closer to true autonomy. The quest to build life from scratch continues to inspire awe and curiosity, offering profound insights into the nature of living systems and the possibilities of engineering biology for the future.
Lori Youmshajekian, a science journalist specializing in health and environmental issues, authored the original report. Her work has appeared in National Geographic, Wired, and other notable outlets. The SpudCell study has been posted on the preprint server bioRxiv and awaits peer review. Scientific American invites readers to support continued science journalism through subscriptions, which sustain reporting on vital scientific discoveries and issues shaping our world.