The feeding fronds of the slime mould Physarum polycephalum turn out to have memory resistance – or memristance. This electronic property can be used to create the data-processing circuits at the heart of all computers. Crucially, a memristor’s electrical resistance is not constant but can be set by applying different voltages so that when the current stops, it “remembers” its resistance until current flows again.
Predicted in 1971 by Leon Chua at the University of California in Berkeley, memristance was only discovered in practice in 2008 in titanium dioxide nanoparticles. Since then, the effect has been found in leaves, human sweat glands and blood – but not in biological material that could be used in computers.
Now Ella Gale and colleagues at the University of the West of England in Bristol have found memristor behaviour in P. polycephalum‘s food-seeking tendrils.
The team says that mould might one day be used to build exotic computers. “Slime mould can be used to perform all the logic functions that conventional computer hardware components can do,” says Gale.
Her team is also exploring whether, in addition to number-crunching, slime mould’s knack for finding the shortest path to nutrients can be used to design the most efficient circuit patterns for biocomputers.
Chua doubts the mould memristors are going to have much of an impact on computer chips of the future, but says the finding underscores how important they are in the biological world, where memristance has evolved to allow organisms to transfer information, such as neural impulses, rapidly and efficiently.
Journal reference: arxiv.org/abs/1306.3414
This article appeared in print under the headline “Memristor slime: logical choice for a biocomputer”