Engineers design ‘living materials’ | MIT News Office

Engineers design ‘living materials’ | MIT News Office: By programming cells to produce different types of curli fibers under certain conditions, the researchers were able to control the biofilms’ properties and create gold nanowires, conducting biofilms, and films studded with quantum dots...

“It’s a really simple system but what happens over time is you get curli that’s increasingly labeled by gold particles. It shows that indeed you can make cells that talk to each other and they can change the composition of the material over time,” Lu says. “Ultimately, we hope to emulate how natural systems, like bone, form. No one tells bone what to do, but it generates a material in response to environmental signals.”

How to Make a Computer from a Living Cell

How to Make a Computer from a Living Cell: The Stanford researchers’ genetic logic gate can be used to perform the full complement of digital logic tasks, and it can store information, too. It works by making changes to the cell’s genome, creating a kind of transcript of the cell’s activities that can be read out later with a DNA sequencer...

The transcriptor triggers the production of enzymes that cause alterations in the cell’s genome. When the production of those enzymes is triggered by the signal—a protein of interest, for example—these enzymes will delete or invert a particular stretch of DNA in the genome. Researchers can code the transcriptor to respond to one, or multiple, different such signals. The signal can be amplified because one change in the cell’s DNA can lead the cell to produce a large amount of the output protein over time.

The most complex synthetic biology circuit yet

The most complex synthetic biology circuit yet: Using genes as interchangeable parts, synthetic biologists design cellular circuits that can perform new functions, such as sensing environmental conditions. However, the complexity that can be achieved in such circuits has been limited by a critical bottleneck: the difficulty in assembling genetic components that don’t interfere with each other...


The pathway consists of three components: an activator, a promoter and a chaperone. A promoter is a region of DNA where proteins bind to initiate transcription of a gene. An activator is one such protein. Some activators also require a chaperone protein before they can bind to DNA to initiate transcription.

The researchers found 60 different versions of this pathway in other species of bacteria, and found that most of the proteins involved in each were different enough that they did not interfere with one another. However, there was a small amount of crosstalk between a few of the circuit components, so the researchers used an approach called directed evolution to reduce it. Directed evolution is a trial-and-error process that involves mutating a gene to create thousands of similar variants, then testing them for the desired trait. The best candidates are mutated and screened again, until the optimal gene is created.

Synthetic Genetic Evolution | The Scientist

Synthetic Genetic Evolution | The Scientist: To see whether XNAs could evolve, they generated random HNA sequences, then selected for those that could bind to two target molecules. After selection, the HNAs were amplified by the newly designed polymerases and again selected for their ability to bind the targets. Eight rounds of selection later, the HNA sequences were no longer random, as those with a particular target-binding motif became more abundant. Through selection and replication, the HNAs had evolved.
The finding in itself is not surprising, said Kool. “Chemists have been working for 20 years to find new backbones for DNA and the feeling always was that it would be interesting and quite possible that some of them might be replicated one day.” It was, nevertheless, impressive, he added. “The hard part was finding the enzymes that could do it. So the big leap ahead for this paper was finding those enzymes.”

Enzymes grow artificial DNA : Nature News & Comment

Enzymes grow artificial DNA : Nature News: The artificial polymers, dubbed XNAs, carry the normal genetic 'alphabet' on a backbone made using different sugars. Scientists have previously developed XNAs that recognize and bind genetic sequences for experimental and biomedical applications, but is it difficult to make them in large quantities.

“Any time you want another XNA molecule, you’ve got to make more, but you can’t copy what you already made — until now,” says Gerald Joyce, a biochemist at the Scripps Research Institute in La Jolla, California.

Holliger and his team engineered enzymes that helped six types of XNA to assemble and replicate genetic messages. The enzymes transcribed DNA into the various XNAs, then back into new DNA strands — with 95% accuracy or more.

Christoph Adami: Finding life we can't imagine | Video on TED.com

Christoph Adami: Finding life we can't imagine | Video on TED.com: How do we search for alien life if it's nothing like the life that we know? At TEDxUIUC Christoph Adami shows how he uses his research into artificial life -- self-replicating computer programs -- to find a signature, a 'biomarker,' that is free of our preconceptions of what life is.

Synthetic yeast will evolve on command - life - 14 September 2011 - New Scientist

Synthetic yeast will evolve on command: Biologists have built two artificial chromosome arms and put them to work in a living yeast. They plan to replace the entire yeast genome over the next five years and then evolve new strains to order...
The artificial yeast are similar to Craig Venter's synthetic cells, announced last year. Venter replaced the entire genome of a bacterium with a synthetic genome – but the task is far harder in yeast, because it is a more complex organism and has a bigger genome...

Life-like cells are made of metal - New Scientist - New Scientist

Life-like cells are made of metal: "I am 100 per cent positive that we can get evolution to work outside organic biology," says Lee Cronin (see photo, right) at the University of Glasgow. His building blocks are large "polyoxometalates" made of a range of metal atoms – most recently tungsten – linked to oxygen and phosphorus. By simply mixing them in solution, he can get them to self-assemble into cell-like spheres.

Scientists construct synthetic proteins that sustain life

Scientists construct synthetic proteins that sustain life: At the heart of his team's research was to question how there are only about 100,000 different proteins produced in the human body, when there is a potential for so many more. They wondered, are these particular proteins somehow special? Or might others work equally well, even though evolution has not yet had a chance to sample them?
Hecht and his research group set about to create artificial proteins encoded by genetic sequences not seen in nature. They produced about 1 million amino acid sequences that were designed to fold into stable three-dimensional structures...
"These artificial proteins bear no relation to any known biological sequences, yet they sustained life," Hecht said.

Reprogramming Life - Technology Review

Reprogramming Life - Technology Review: Development of a high-level language for programming genetic systems