Circuit breakers, oscillators and sensors – familiar components for electronic circuits; made of yeast cells – not so familiar. That’s where the synthetic biology research at the University of Gothenburg (Sweden) is heading. As described in a paper published in Nature [Distributed biological computation with multicellular engineered networks] an international team led Stefan Hohmann created genetically modified yeast cells that have two key (engineered) capabilities: they sense specific chemical/molecular properties of their environment, and they respond by producing specific molecular signals. This is a rudimentary but functional communications chain, which can be, in effect, a circuit.
Building upon earlier research into the information transmission pathways (chemical chain reactions) found in naturally occurring cells, the researchers in Sweden and Spain isolated the genetic components responsible for this kind of molecular/chemical transmission. Then they began to (re)engineer the genetic code to produce specific molecules for transmission pathways. The result was several different kinds of yeast cells that respond to highly specific molecules in their environment and in turn produced other highly specific molecules as a signaling mechanism. As in a circuit, the signaling molecules of one yeast cell become the molecules sensed by another yeast cell.
In the current work, the synthesized yeast cells with several different chemical/molecular properties were combined to form simple analogs to electronic logic components. Logic components – elements that perform ‘logic’ (AND, OR, NOT) – are fundamental to computers, especially in the central processing unit (CPU). The approach used by this research is based on combining individual cells. Other approaches use molecules within one cell.
While there is some truth to the claim that this is a step in the direction of a biological computer, the distance between this proof of principle demonstration and some kind of functional computer is still enormous. This is especially true in the context of producing a biological computer that in some way competes with the ‘hardware’ (conventional) computer. It is more likely that computers using biological components will be used for computational tasks within biological systems (for example, the human body). They probably won’t compete on speed or sophistication, compared to traditional computers, but they should integrate better with living things.
“Even though engineered cells can’t do the same job as a real computer, our study paves the way for building complex constructions from these cells,” says Kentaro Furukawa at the University of Gothenburg’s Department of Cell- and Molecular Biology, one of the researchers behind the study. “In the future we expect that it will be possible to use similar cell-to-cell communication systems in the human body to detect changes in the state of health, to help fight illness at an early stage, or to act as biosensors to detect pollutants in connection with our ability to break down toxic substances in the environment.”