Technology breakthrough might eventually be used by pathologists to help diagnose disease using in vivo diagnostic testing methods
Researchers at Stanford University are another step closer to understanding how to make DNA and RNA function like computer chips fabricated from silicon. Their work could eventually form the basis for new types of diagnostic services that could be offered by clinical laboratories and anatomic pathology groups.
Stanford Bioengineers Develop Final Component for Biological Computer
Bioengineers at Stanford University have engineered a genetic circuit to behave like a transistor in individual living cells, according to a story published by the San Jose Mercury News. The achievement represents the final component of a simple biological computer that functions within individual cells of the body.
These biological computers could be used in several ways. They could screen for cancer, or be used to detect the presence of toxic chemicals. Some experts believe they could be used to guard against disease, reported the Mercury News.
“We’re going to be able to put computers inside any living cell you want,” declared lead researcher Drew Endy, Ph.D. of Stanford’s School of Engineering.
How the Stanford Team’s ‘Transcriptor’ Works in the Human Body
The Stanford team detailed its new “transcriptor” in the March 28 issue of Science. The new component is composed of DNA and RNA and is the biological equivalent of a digital transistor. It functions like the transistor’s semiconducting material, which controls the flow of electrons along a circuit.
The approach relies on changing the state of double-stranded DNA, the editors of Science noted in their summary. The transcriptor regulates the flow of the protein RNA polymerase along a strand of DNA.
“If this were electronics, DNA is the wire and RNA polymerase is the electron,” Stanford School of Medicine writer Andrew Myers explained in a press release issued by Stanford University.
Creating the Missing Third Component in Bio-Computing
According to Wikipedia, modern computers require three different capabilities:
- the ability to store information
- he ability to transmit information between components, and
- a basic system of logic.
Scientists had already successfully demonstrated the ability to store and transmit data using biological components made of proteins and DNA. The logic system remained the missing component required to build a biological computer.
Last year, the Endy team delivered the other two core components of a biological computer, according to the Mercury News story. The first component was a type of rewritable digital data storage within DNA. The second component was a mechanism for transmitting genetic data from cell to cell.
Creating a Transcriptor That Acts as a Logic Gate
The latest research effort added the third critical component—the transcriptor that acts as a “logic gate.” The logic gate determines whether a biochemical question is true or false, reported a story in UK’s The Independent.
“We have repurposed a group of natural proteins, called integrases, to realize digital control over the flow of RNA polymerase along DNA, which in turn allowed us to engineer amplifying genetic logic,” stated Endy in the Stanford School of Medicine press release.
The researchers designed and constructed six basic logic gates based on the activity of two serine recombinases, noted the study authors in Science. In computer science, transistors called Boolean logic rules.” Endy calls his transcriptor equivalent Boolean Integrase Logic gates—“BIL” gates, for short.
According to blogger, Robert T. Gonzales, there is one big take-away from this research breakthrough: When multiple logic gates are lined up, a logic circuit is formed. Next, string together enough logic circuits and a computer is created that can handle just about any computation, whether it involves mathematics or gene expression inside a cell.
Bio-Computing Would Give Pathologists a New Diagnostic Tool
The ability to implement computing capability within living organisms would have profound impact on the study and treatment of diseases. For pathologists and clinical laboratory directors, this new technology could help shape a future where laboratory medicine expertise will be based more on the value of consultations with physicians than a simple reporting of test results performed in a medical laboratory.
—Pamela Scherer McLeod