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Live wires - The blueprint of life is helping to shrink electronics

点击量:   时间:2018-02-25 07:01:06

By Ben Crystall DNA could soon help tiny electrical circuits to build themselves, Israeli researchers predict. Using tiny strands of DNA as templates, they have “grown” silver wires that are just a few nanometres wide between two electrodes. As electrical circuits become ever smaller, it will eventually become impossible to build them using conventional techniques such as photolithography. So Erez Braun and his colleagues at the Technion-Israel Institute of Technology in Haifa turned to the remarkable properties of DNA for help. “Self-assembly with DNA is well developed in nature,” says Braun’s colleague Uri Sivan. “The whole toolbox is already there.” First, the researchers chemically anchored short DNA strands 12 base pairs long onto the surface of tiny gold electrodes. These acted as selective hooks for a longer strand of DNA, forming a bridge between the electrodes. They then added positively charged silver ions, which stuck to the negatively charged DNA. Reducing the ions to silver metal particles with a solution of hydroquinone created a silver wire bridge 12 micrometres long between the electrodes, they say in this week’s Nature (vol 391, p 775). The beauty of the technique is its flexibility, Braun says. By changing the anchor’s base pairs, Braun and his team can select where the DNA will bind. So with a network of electrodes carrying different anchors, each targeting DNA bridges of different lengths, it should be possible to make a nanocircuit to order. However, the technique has its drawbacks. The silver wires have unusually high resistance, possibly due to poor electrical contact between the silver grains. Braun’s team hopes to improve the connections, for instance by using gold, which is a better conductor than silver. “The next challenge is to self-assemble a transistor using the same techniques,” says Sivan. Braun says their work confirms that using DNA and proteins as templates for building nanoscale electronics is feasible. “There are not many other ways,