Creating synthetic life in a lab? SpudCell falls short of the goal, but raises even more useful questions
Nature is a double-edged sword. It's both a source of life and a cause of destruction. From forests to coral reefs to human life, nature's biological systems are awe-inspiring. But they can also bring about infections, cancer, genetic diseases, crop blights, and toxins. While natural processes can heal and sustain, they can also destroy.
This dichotomy drives the field of synthetic biology, where scientists apply engineering principles to learn from and adapt nature's biological systems to address human problems. By understanding these systems, scientists can redirect them when natural processes cause harm.
As a biomedical engineer, I've dedicated my career to this pursuit. My lab studies how to program cells to better understand their behavior and ultimately use them as medicine. Our goal is not to discard or replace nature but to learn from biological principles and use that knowledge responsibly to help society.
The recent announcement of SpudCell, a synthetic cell built from purified, nonliving components, has sparked curiosity and debate. What does it take to build a cell from scratch? If scientists assemble something that feeds, grows, copies genetic material, and divides, have they created life?
The Bottom-Up Approach
Natural cells are incredibly complex. Researchers are using synthetic cells to learn more about life's basic features by rebuilding them in a simpler, more understandable form. Earlier designs of minimal cells, which test the necessary components for lifelike behavior, started with existing living cells and reduced their genomes. While these minimal cells are useful, they often lack the autonomy, resilience, metabolism, and evolutionary capacity of natural cells.
Synthetic cells, on the other hand, are built through a bottom-up engineering approach. Scientists start with a simplified compartment, a biological 'box', and ask what must be added for it to behave more like a living cell. A membrane separates the inside from the outside, genetic material stores instructions, molecular machinery reads those instructions to make molecules, energy sources power reactions, and other components allow growth, division, and adaptation.
SpudCell's Assembly
SpudCell was assembled from the bottom up using purified, nonliving parts. Researchers used lipid molecules to create a cell-like membrane, DNA molecules to store genetic instructions, purified enzymes to copy and read those instructions, and other molecular machinery to build proteins and other molecules from small chemical building blocks like amino acids and nucleotides.
What Makes SpudCell Exciting
SpudCell is exciting because it appears to bring several features of life together in one system. The researchers describe it as capable of feeding, growth, genome replication, genetically encoded division, and something close to evolution. These features resemble a biological cell cycle.
However, SpudCell falls short of being a fully synthetic living cell. A membrane-bound compartment containing DNA is not automatically a living cell, just as a pile of car parts is not a car. SpudCell can carry out life-like processes, but it is not independent. It still relies on carefully controlled laboratory conditions and researchers to supply its molecular machinery.
The Quest for Autonomy
To approach life, a synthetic cell must coordinate multiple processes simultaneously. NASA defines life as a 'self-sustaining chemical system capable of Darwinian evolution', meaning it must independently use energy, copy information, grow, divide, respond to its surroundings, and persist over time. Natural cells have achieved this with extraordinary reliability due to billions of years of evolution.
SpudCell, however, depends on researchers to continuously supply it with the molecular machinery to function and physically help it divide. It also cannot reproduce indefinitely outside a carefully controlled laboratory environment. In essence, SpudCell may have been built rather than born, but it is not yet autonomous life.
The Value of Synthetic Cells
Despite its limitations, SpudCell is scientifically valuable. It exposes what is still missing to create life, raising questions about essential parts, coordinated processes, and the necessary complexity before chemistry begins to resemble biology.
Practical Applications
Answering these questions has practical importance. Synthetic cells can help scientists and engineers design safer biological systems for various industries. They can be simplified test beds for studying biological circuits, disease mechanisms, and the origins of life.
Synthetic cells can also be used to build safer systems for making medicines, fuels, or materials, detecting environmental toxins, or delivering therapies without relying on fully living organisms. They can act as simplified biological factories or biosensors, providing early warnings of dangerous threats like bioweapons.
The Philosophical Question
The philosophical question, 'Is SpudCell alive?' may not have a simple yes or no answer. The boundary between living and nonliving depends on the definition of life, which can emphasize metabolism, reproduction, evolution, autonomy, or cellular organization.
Life is not defined by a single property. Viruses contain genetic information but depend on host cells to reproduce. Mitochondria perform essential metabolism but cannot live independently outside cells. A seed can remain dormant for years before resuming growth.
Guiding Synthetic Biology with Responsibility
Synthetic biology should be guided by a strong sense of responsibility. Scientists can learn to redirect harmful processes, build safer tools, and help society by asking whether biological systems can be built and whether their creation should be controlled, where they should function, and what safeguards are needed.
Over the past two decades, scientists have built many kinds of biological kill switches, genetic circuits that can shut down engineered cells under specific conditions. Some researchers have made cells dependent on a specific nutrient, while others have created cells that can survive only in a particular environment or activate self-destructive pathways when conditions change.
Kill switches are not magic off buttons but an important example of synthetic biology's moral compass. They remind us to build useful biological tools with safety, accountability, and humility in mind.
