With their microscopic view of the universe, physicists at UCSB will soon be joining biologists — with their characteristically macroscopic view of nature — in the search for the origin of life.
Albert Libchaber, a professor of physics visiting from Rockefeller University, gave a talk at the UCSB Kavli Institute for Theoretical Physics (KITP) on Wednesday about his latest research into artificially creating cell-like structures. In his lab, Libchaber created tiny vesicles that provide a way to model what life might have looked like in its earliest stages. Researchers at UCSB plan to conduct their own studies that may answer long-standing questions about how life started. Since all cells are produced by other living cells, the question of how the world’s first cells were created has so far been unanswered.
Libchaber conducted experiments in which he created artificial cells, called vesicles, which were able to draw nutrients from a surrounding fluid, but not reproduce. Libchaber constructed the vesicles by extracting fluid from E. coli bacteria and enclosing it in a laboratory-made membrane called a lipid bilayer.
In normal cells, the bilayer is filled with pores that allow the cell to absorb crucial nutrients from the surroundings and expel waste. In the laboratory-made bilayer, the pores were created artificially by attaching proteins to the bilayer that act as a sort of doorway.
“This is not a cell, it is an artificial bilayer,” Libchaber said. “The pores are sized such that small molecules can enter the vesicle.”
The vesicles in Libchaber’s experiment did not have any DNA of their own and were unable to reproduce, but they were able to metabolize nutrients. This was proven by the presence of a chemical that the vesicles created as a byproduct — similar to a factory that takes in raw materials and produces a product. The next big step in these types of experiments will be giving the vesicles instructions to reproduce themselves.
“Nature is full of self-creating machinery,” Libchaber said. “So far, we have been unable to do it.”
Deborah Fygenson, professor of physics who listened to Libchaber’s talk, said the chemicals needed to create a cell were known to exist on earth, but scientists are unsure how those chemicals interacted with each other to create a self-reproducing cell.
“It’s about the most interesting class of problems we have in nature,” Fygenson said. “Now the question is, ‘Can you get the dynamics?'”
At the KITP, permanent member Boris Shraiman said that physicists are becoming increasingly involved in studying biology.
“I think the key message is that biology is a rapidly developing field and physicists are getting interested,” Shraiman said. “Physicists often view things from a different viewpoint than biologists.”
Fygenson and Shraiman said UCSB will soon be conducting experiments that aim to discover how Earth’s first cells may have arisen and started to reproduce. The KITP and the Physics Dept. will each be starting on projects to answer these questions about early life.
“We are running programs on interdisciplinary biology,” Shraiman said. “There will be a mini workshop here in a few weeks on growth, death and aging.”
Despite the incredible difficulties in creating a self-replicating entity, Libchaber said the immense interest among scientists will help produce results.
“I believe we will eventually achieve self-replication of the vesicles,” Libchaber said.
The thought of creating something that can utilize nutrients and self-reproduce will also bring up questions about whether life itself can be created, Fygenson said.
“There’s that interesting point between just having a bunch of materials, and having something living,” Fygenson said.