Small, quivering orbs designed to feed and reproduce and enhance the view of artificial organisms
Scientists claim they are closer to creating life from scratch after building tiny, quivering blobs that use lab-made DNA to feed, grow and reproduce in a dish.
According to a report published in The Guardian, the synthetic cells were made from chemical compounds and are believed to be the first to demonstrate the complete cell cycle of growth, genetic replication and division to produce the next generation.
The work raises the prospect of artificial organisms designed and built to secrete substances, food, fuels and other materials. But it can also shed light on the profound question of how particular collections of inanimate matter cross a threshold to become life.
Dr. Kate Adamala, who led the research at the University of Minnesota, said: “It’s not as robust, as fast or as good at most of its functions as a natural cell, but it’s a proof of principle that molecules can reconstitute behavior that we’ve only associated with natural living cells until now. If we’re going to be able to engineer biology, we really need to understand so we can know exactly which component we have.”
Scientists have been trying to create synthetic life for decades. In 2010, late genetics pioneer Craig Venter built an organism based on a bacterium that causes mastitis in goats. Others have achieved similar feats.
Instead of modifying natural cells, Adamala’s team built SpudCells from the ground up, ensuring that every component was known and understood. They started with small water-filled spheres called liposomes, which are a few thousandths of a millimeter wide, and added a small amount of synthetic DNA to provide basic functions. Adamala calls them SpudCells to evoke Sputnik and the dawn of the space age, but that’s not the only reason. “I’m Polish,” she said. “I’m mostly made of potatoes.”
SpudCells only work in a liquid filled with vital chemicals such as ATP, the main energy-carrying molecule that living cells make from nutrients. To grow, SpudCells fuse with tiny “feeder” liposomes in the liquid. These contain molecules, enzymes and microscopic structures called ribosomes that SpudCells need to make proteins. SpudCell’s genome carries other instructions for copying its genome and parts.
To mimic the evolutionary concept of survival of the fittest, the researchers showed how SpudCells with a genetic growth advantage spread through the population and outcompeted original SpudCells. Prof Tom Ellis of Imperial College London said the work was probably the field’s “biggest breakthrough in recent times”.
“Making a synthetic cell helps us understand the exact minimum requirements for life and how life could have arisen from chemistry,” Ellis said. “It is also useful as it provides a fully understood system for testing biological circuits and computer models of cellular life.”
Seeing SpudCells split was striking to witness, Adamala said. “They’re among the most beautiful pictures I’ve seen, but obviously I’m biased. To most people, when they look at it under the microscope, it doesn’t look like much… It’s a blob.” SpudCells are not alive, but can become a chassis to build life with, she added.
For Adamala, the work is a proof of principle that synthetic cells can behave like living cells. But they are not nearly as capable as living cells. SpudCells are completely dependent on the substances and components of the fluid they are immersed in. They cannot build their own protein-making machinery, control their metabolism, or clear their waste. And when they divide, they often pass on the wrong amount of DNA. They disappear after a few generations.
Adamala and others launch an institution called Biotic to pool global expertise and build SpudCells into something more impressive. The aim, according to co-founder Prof Drew Endy, a bioengineer at Stanford University, is to build “an operating system for life” made of genes and biochemistry. The study has been published as a preprint before peer review so that other laboratories can review the work without delay.
Prof John Dupré, a philosopher and founder of the Center for the Study of Life Sciences at the University of Exeter, questioned the point of such synthetic cells and whether they would be more effective in producing medicine, food, fuel and materials than modified bacterial cells. They may not tell us much about life either, he added. “It might provide a convincing argument against those who believe that there is an immaterial substance beyond the chemicals that breathe life into material things. But almost no scientist believes this now,” he said.
“What’s missing, I think, is the relational aspect of life, which has become evident in the growing recognition that life is almost universally symbiotic,” he added. “If synthetic cells are only used to produce valuable chemicals, this relational aspect may be absent, but so would one of the most interesting aspects of actual living beings.”
