Protein: a natural memory device?
doi:10.1038/nindia.2013.47 Published online 1 April 2013
A group of researchers working at the fascinating intersection of biology and electronics have come up with an equally fascinating find — that protein, present in all forms of life, has memory. And that this memory can be harnessed to make bio-memristor devices.
The team led by Chinmay Maiti of the Indian Institute of Technology (IIT) Kharagpur has shown that different types of proteins — from plant sources such as papaya or rubber, or animal sources such as bovine serum or wax silk — can be converted into bio-memristor devices with switching properties. Memristor devices are electronic circuits which remember changes in the current passing through them by changing their resistance.
"By exploring what these devices would do, probably some day in future, it will be possible to solve the puzzle of how nature makes the most delicate and powerful computer – the brain," Maiti told Nature India.
Their first success was with natural silk fibroin protein1 isolated from the cocoons of the silkworm Bombyx mori . They used the protein as a biomaterial for a memristor device. The team has now observed similar switching properties in different types of natural proteins. "We are observing the same phenomenon in all proteins studied so far. This has inspired us to think that memory is a 'fundamental' property of proteins," Maiti says.
Maiti says researchers around the globe are trying to mimic Nature to make the best possible computer — one like the human brain — by following the activity of proteins and there's been a lot of research on protein memory. "However, what we wish to say is that protein itself is a memory device. This has not been shown thus far," he says.
Protein memory may have something to say about how biological organisms learn. "Associative memory is the fundamental human ability to correlate different memories to the same event simultaneously. Evidence of memory effects observed in proteins will help us understand the human brain better," Maiti adds.
As amino acid sequences and molecular architecture of proteins become known gradually, it will be important to understand the relationship of the protein structure and memory function, he says.
Proteins could be put to use in large scale integration circuit designs as well as in biologically-inspired synapse links for energy-efficient computing that mimic information processing in nerve cells.
The team is hoping to publish their latest work soon where they report natural papaya latex as a dielectric for the fabrication of resistive switching devices. They have observed bipolar resistive switching phenomena in metal-insulator-metal structures with papaya latex.
This bipolar switching behaviour in papaya latex may find its application in bioinspired memory circuit applications, the researchers add.
- Hota, M. K. et al. Natural silk fibroin protein-based transparent bio-memristor. Adv. Funct. Mater. 22, 4493-4499 (2012)