For the first time ever, a team of researchers from the University of Georgia (UGA) and Israel's Ben-Gurion University has created the world's smallest diode using a single DNA molecule. The finding represents a step forward in the search for silicon chip replacements and could lead to the creation of electronic devices that are smaller and more powerful.
"For 50 years, we have been able to place more and more computing power onto smaller and smaller chips, but we are now pushing the physical limits of silicon," said Bingqian Xu, an associate professor at UGA. "If silicon-based chips become much smaller, their performance will become unstable and unpredictable."
Xu and his team turned to DNA molecules for a solution to the problem, citing the predictability, diversity and programmability of the organic building blocks as the main reasons that it is a strong candidate for the design of nanoscale electronic components.
The team isolated a specifically designed single duplex DNA of 11 base pairs and attached it to a nanoscale electronic circuit that measured just a few nanometers. Compared to the 3 billion base pairs in the human genome, this DNA molecule is a very short helix.
While nothing special occurred at first, after the team intercalated a small coralyne molecule onto specific sites on the DNA, they noticed that the current flowing through the molecule was 15 times stronger for negative voltages than for positive voltages. This is a necessary feature of a diode, a vital component of electronic devices that allows current flow in one direction and blocks it in the other.
"This finding is quite counterintuitive because the molecular structure is still seemingly symmetrical after coralyne intercalation," Xu said.
Yanantan Dubi, a researcher from Ben-Gurion University, claims that DNA's diode-like behavior stems from the coralyne insertion, which leads to a voltage-induced disrupting of its spatial symmetry.
"Our discovery can lead to progress in the design and construction of nanoscale electronic elements that are at least 1,000 times smaller than current components," Xu said.
The team hopes to that their creation of the world's smallest diode using a single DNA molecule will open up to path to more nanoscale electronics with a higher level of complexity thanks to scaled down component sizes, as well as improve the performance of the molecular diode.
The findings were published in the April 4 issue of Nature Chemistry.
