Arizona State University ~ ‘Living Computers’ from RNA for Nanotechnology

Researchers from Arizona State University have demonstrated that living cells can be induced to carry out complex computations in the manner of tiny robots or computers.

It’s an example of engineers and biologists coming together to create an innovative solution to the performing of calculations. The implications are a potential game-changer for intelligent drug design and smart drug delivery. Other fields that could be affected include green energy production, low-cost diagnostic technologies and the development of futuristic nanomachines to be used in gene-editing. The basis of the new technology is the natural interactions between nucleic acid; in this case the predictable and programmable RNA-RNA interactions. RNA is ribonucleic acid, an important molecule with long chains of nucleotides.

A nucleotide contains a nitrogenous base, a ribose sugar, and a phosphate. RNA is involved with the coding, decoding, regulation, and expression of genes. This builds on earlier work where DNA and RNA, the molecules of life, where demonstrated as being able to perform computer-like computations by Leonard Adleman (University of Southern California) in 1994 (“Molecular Computation of Solutions To Combinatorial Problems.”)

Atomic structure of the 50S Large Subunit of the Ribosome. Proteins are colored in blue and RNA in orange. RNA is central to the synthesis of proteins. Wikipedia / Vossman

From this basis, lead researcher Professor Alex Green has used computer software to design RNA sequences that behave the way researchers want them to in a cell. This makes the design process a much faster.The output is circuit designs, which look like conventional electronic circuits, but which self-assemble inside bacterial cells. This allows the cells to sense incoming messages and respond to them by producing a computational output. To test this out, the researchers worked with specialized circuits called logic gates. The tiny circuit switches were tripped when messages (RNA fragments) which attached themselves to their complementary RNA sequences in the cellular circuit. This activated the logic gate and produced an output. A series of more complex logic gates were then designed, to respond to multiple inputs. Here logic gates known as AND, OR and NOT were designed.

The video below explains more about these switches:

From this the scientists developed the first ribocomputing devices capable of four-input AND, six-input OR and a 12-input device able to carry out a complex combination of AND, OR and NOT logic known as disjunctive normal form expression.The great strength of the new method is with its ability to perform many operations at the same time. This capacity for parallel processing allows for faster and more sophisticated computation.The example, of meshing engineering and biology together, is part of an emerging field called synthetic biology, and it is one of the fastest growing areas of scientific research. In a sense, synthetic biology is a biology-based “toolkit”. According to the European research group ERBC the science deploys abstraction, standardization, and automated construction to change how we build biological systems and expand the range of possible products. One such example of what a highly accurate platform like this could do is with diagnosing viruses the Zika virus.The research has been published in the journalNature under the title “Complex cellular logic computation using ribocomputing devices.”