Envelope for an artificial cell

Jan 25, 2012
Neal Davaraj watches as undergraduate student Weilong Li works on a next step in their quest to create an entirely artificial cell.

(PhysOrg.com) -- Chemists have taken an important step in making artificial life forms from scratch. Using a novel chemical reaction, they have created self-assembling cell membranes, the structural envelopes that contain and support the reactions required for life.

Neal Devaraj, assistant professor of at the University of California, San Diego, and Itay Budin, a graduate student at Harvard University, report their success in the .

“One of our long term, very ambitious goals is to try to make an artificial cell, a synthetic living unit from the bottom up – to make a living organism from non-living molecules that have never been through or touched a living organism,” Devaraj said. “Presumably this occurred at some point in the past. Otherwise life wouldn’t exist.”

By assembling an essential component of earthly life with no biological precursors, they hope to illuminate life’s origins.

“We don’t understand this really fundamental step in our existence, which is how non-living matter went to living matter,” Devaraj said. “So this is a really ripe area to try to understand what knowledge we lack about how that transition might have occurred. That could teach us a lot – even the basic chemical, biological principles that are necessary for life.”

Molecules that make up cell membranes have heads that mix easily with water and tails that repel it. In water, they form a double layer with heads out and tails in, a barrier that sequesters the contents of the cell.

Devaraj and Budin created similar molecules with a novel reaction that joins two chains of lipids. Nature uses complex enzymes that are themselves embedded in membranes to accomplish this, making it hard to understand how the very first membranes came to be.

“In our system, we use a sort of primitive catalyst, a very simple metal ion,” Devaraj said. “The reaction itself is completely artificial. There’s no biological equivalent of this chemical reaction. This is how you could have a de novo formation of membranes.”

They created the synthetic membranes from a watery emulsion of an oil and a detergent. Alone it’s stable. Add copper ions and sturdy vesicles and tubules begin to bud off the oil droplets. After 24 hours, the oil droplets are gone, “consumed” by the self-assembling membranes.

Although other scientists recently announced the creation of a “synthetic cell,” only its genome was artificial. The rest was a hijacked bacterial cell. Fully will require the union of both an information-carrying genome and a three-dimensional structure to house it.

The real value of this discovery might reside in its simplicity. From commercially available precursors, the scientists needed just one preparatory step to create each starting lipid chain.

“It’s trivial and can be done in a day,” Devaraj said. “New people who join the lab can make membranes from day one.”

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5 / 5 (7) Jan 25, 2012
The only acceptable explanation at the moment is that someone with highly complex tools and intelligence took the first step to form both at the same time. Any other explanation relies on extremely improbable physical events occurring - so improbable as to be in the realm of fairy tales.

Just because we do not fully understand this detail right now does mean that the correct answer is to chalk it up to intelligent design. Yes, the odds are astronomical, but so are the odds of winning the lottery, yet almost every week someone hits the jackpot. And we aren't talking about throwing some molecules into a petri dish and waiting 20 minutes. We are talking about the combined surface area of every planet in the universe over the course of 13 billion years.
not rated yet Jan 25, 2012
I wonder if we are missing - and we probably are - the fact that the first cell membranes were terribly ineffecient and that those effiecienies came much later in the evolutionary path. What if the first membreanes just flat out sucked -- and very much the interior of the cell was close if not identical to the exterior environment.

that seems more in line with evolutionary pricipals than trying to create what we currently observe.

@kevin -- please remember that science tries to determine what could happen naturally based on observation of what is going on. To experiment with an "evolutionary" process is to conjecture what might have happened at an unobservable time based on the "laws" of nature not changing over vast time scales. This seems reasonable parameters on which experimentation of this sort happens.
5 / 5 (1) Jan 25, 2012
the first cells probably "ate" raw chemicals / molecules and were very much simple chemical reaction factories.

indeed Kevin science has no answer with the evolution paradigm as to how proceation started -- and niether why or how the sexes developed with one species... indeed fertilization seems extreme from a chemical standpoint -- and ineffecient.

in the attempt to debunk evolution those knowledgable in the subject should attack its weaknesses not it's strengths as an arguement.

Attack what evolution cannot explain gracefully - this is the way to tear down a paradigm -- but unfortunately you will in the process create a new paradigm that is stronger and more complete.
5 / 5 (3) Jan 25, 2012
KevinRTRS, do you ever stop being disingenuous? Ever? You do realize that you're basically a liar every time you make statements like yours, right? And isn't that breaking one of those ten commandments? What about Thou Shalt Not Bear False Witness?
1 / 5 (4) Jan 25, 2012
IMO the life really started from liposomes, which were gradually selected by its stability and speed of growth with mechanical action of their environment. http://aetherwave...ife.html Such liposomes can behave like walking droplets, described recently. We can imagine, such droplets were precipitated from waves of ancient lakes at places, where organic compounds were pre-concentrated by wind and solar radiation and they were thrown at coast surface, covered by various surfactants. The droplets are attracted to them, so they started to climb around coast, collecting these materials in their cells. The most successful droplets become so large by such way, they fragmented into smaller ones under impact of next breaker wave, and whole process has repeated many times.
1 / 5 (3) Jan 25, 2012
3.7 / 5 (3) Jan 25, 2012
I can't wait for the researchers to create the first working artificial cell - the complexity will blow them away!
IMO the first cells were prepared already and they're quite simple. They're moving spontaneously, "eating" and "seeking" for food. They can divide and multiply too. http://focus.aps..../v15/st7 The rest is just many years standing selection and optimization of their chemical composition. Try to imagine, for example, some cell will accidentally a trap the chemical, which will improve the mechanical stability of its membrane with polymerization. During few weeks such cells will multiply by division and completely outnumber the less advanced cells.
5 / 5 (2) Jan 26, 2012
Kev you do realise the Bible is the origonal book of fairy tales?

Also i am suprised you basically said aliens were responsable for life here, you are usually such a Bible Humper? Are you ok?
not rated yet Jan 26, 2012
and of course the rest of physorg is silly enough to attack the Bible instead of Kevin's argument -- proving they know as little about for to argue against Creationism as kevin is bad at arguing against science.
not rated yet Jan 26, 2012
and of course the rest of physorg is silly enough to attack the Bible instead of Kevin's argument -- proving they know as little about for to argue against Creationism as kevin is bad at arguing against science.

Nobody attacks his arguments because he never had a legitimate argument. He doesn't know anything about science. Liposomes form spontaneously in solution because they're energetically favorable. Lipid membranes don't need any fancy handiwork to form.

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