This past May, Colossal Biosciences hatched 26 baby chickens from artificial eggs. Each synthetic egg had a 3-D printed plastic shell with hexagonal holes. Inside was a thin membrane made of rubber-like silicone that allowed gases like oxygen and carbon dioxide to pass through. This membrane encased and protected the developing chicken embryos.
Next, Colossal plans to engineer a shell about 10 times bigger to fit larger bird species. The company’s ultimate goal is to combine DNA from an extinct species, like the dodo or giant moa, with that of a close living relative, and grow the resulting chicks inside artificial eggs. Vinny Lynch, a biologist at the University of Buffalo in New York, is skeptical about this effort. “The bigger the egg gets, the harder it is to get oxygen in and carbon dioxide out,” he says. That exchange, he explains, is “crucial for life.”