“The membranes we created, though completely synthetic, mimic several features of more complex living organisms, such as the ability to adapt their composition in response to environmental cues,” said Neal Devaraj, an assistant professor of chemistry and biochemistry at UC San Diego who headed the research team, which included scientists from the campus’ BioCircuits Institute.
“Many other scientists have exploited the ability of lipids to self-assemble into bilayer vesicles with properties reminiscent of cellular membranes, but until now no one has been able to mimic nature’s ability to support persistent phospholipid membrane formation,” he explained. “We developed an artificial cell membrane that continually synthesizes all of the components needed to form additional catalytic membranes.”
A time-lapse video of a vesicle that increases in size (in terms of both inner vesicular volume and membrane surface area). Membranes were labeled with a fluorescent dye. Images were acquired at 60 second intervals. Movie duration represents 12 hours of imaging. Scale bar represents 3 µm. Frame rate = 30 frames per second.
The scientists said in their paper that to develop the growing membrane they substituted a “complex network of biochemical pathways used in nature with a single autocatalyst that simultaneously drives membrane growth.” In this way, they added, “our system continually transforms simpler, higher-energy building blocks into new artificial membranes.”
“Our results demonstrate that complex lipid membranes capable of indefinite self-synthesis can emerge when supplied with simpler chemical building blocks,” said Devaraj. “Synthetic cell membranes that can grow like real membranes will be an important new tool for synthetic biology and origin of life studies.”