{"id":280000,"date":"2019-07-02T18:00:15","date_gmt":"2019-07-02T22:00:15","guid":{"rendered":"https:\/\/news.harvard.edu\/gazette\/?p=280000"},"modified":"2023-11-08T20:32:49","modified_gmt":"2023-11-09T01:32:49","slug":"harvard-researchers-present-nanowire-devices-update","status":"publish","type":"post","link":"https:\/\/news.harvard.edu\/gazette\/story\/2019\/07\/harvard-researchers-present-nanowire-devices-update\/","title":{"rendered":"Combing out a tangled problem"},"content":{"rendered":"\n\t
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Charles M. Lieber and his team have been updating nanowire devices, which could encourage faster regrowth after implantation in the brain.<\/p>

Rose Lincoln\/Harvard file photo<\/p><\/figcaption><\/figure>\n\n\t

\n\t\t\t\n\t\t\tScience & Tech\t\t<\/a>\n\t\t\n\t\t

\n\t\tCombing out a tangled problem\t<\/h1>\n\n\t\n\t\t\t<\/div>\n\t\t\n\t
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\n\t\tCaitlin McDermott-Murphy\t<\/p>\n\t\t\t

\n\t\t\tHarvard Correspondent\t\t<\/p>\n\t\t\t\t\t<\/address>\n\t\t<\/div>\n\n\t\t

\n\t\t\tA new technique speeds creation of nanowire devices, boosting research into what\u2019s happening inside cells\t\t<\/h2>\n\t\t\n<\/header>\n\n\n\n
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Machines are getting cozy with our cells. Embeddable sensors record how and when neurons fire; electrodes spark heart cells to beat or brain cells to fire; neuron-like devices<\/a> could even encourage faster regrowth after implantation in the brain.<\/p>\n

Soon, so-called brain-machine interfaces could do even more: monitor and treat symptoms of neurological disorders like Parkinson\u2019s disease, provide a blueprint to design artificial intelligence, or even enable brain-to-brain communication<\/a>.<\/p>\n

To achieve all of this and more, devices need a way to literally dive deeper into our cells to perform reconnaissance. The more we know about how neurons work, the more we can emulate, replicate, and treat them with our machines.<\/p>\n

Now, in a paper published in Nature Nanotechnology, Charles M. Lieber<\/a>, the Joshua and Beth Friedman University Professor, presents an update to his original nanoscale devices for intracellular recording<\/a>, the first nanotechnology developed to record electrical chatter inside a live cell. Nine years later, Lieber and his team have designed a way to make thousands of these devices at once, creating a nanoscale army that could speed efforts to find out what\u2019s happening inside our cells.<\/p>\n

Prior to Lieber\u2019s work, similar devices faced a Goldilocks conundrum: Too big, and they would record internal signals but kill the cell. Too small, and they failed to cross the cell\u2019s membrane \u2014 recordings ended up noisy and imprecise.<\/p>\n

Lieber\u2019s new nanowires were just right. Designed in 2010, the originals had a nanoscale V-shaped tip with a transistor at the bottom of the V. This design could pierce cell membranes and send accurate data back without destroying the cell.<\/p>\n

But there was a problem. Siliconnanowires are far longer than they are wide, making them wobbly and hard to wrangle. \u201cThey\u2019re as flexible as cooked noodles,\u201d said Anqi Zhang<\/a>, a Ph.D. student in the Department of Chemistry in the Graduate School of Arts and Sciences and a member of the Lieber Lab. Zhang is a co-author on the team\u2019s latest work.<\/p>\n

To create the original devices, lab members had to ensnare one nanowire noodle at a time, find each arm of the V, and then weave the wires into the recording device. Two devices took two to three weeks to make.\u201cIt was very tedious work,\u201d said Zhang.<\/p>\n

But nanowires are not made one at a time; they\u2019re made en masse\u00a0<\/em>like the thing they resemble: cooked spaghetti. Using the nanocluster catalyzed vapor-liquid-solid method<\/a>, with which Lieber created the first nanowires, the team built an environment where the wires could germinate on their own. They can pre-determine each wire\u2019s diameter and length but not how the wires are positioned once ready. Even though they grow thousands or even millions of nanowires at a time, the end result is a tangled mess.<\/p>\n\r\n\t\n\n\t

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A U-shaped nanowire pierces the membrane of a neuron. Courtesy of The Lieber Research Group\t\t\t<\/figcaption><\/figure>\n\t\n\t\r\n\n

The solution? Lieber and his team designed a trap for their loose cooked noodles: They made U-shaped trenches on a silicon wafer and then combed the nanowires across the surface. The combing process untangles the mess and deposits each nanowire into a neat, U-shaped hole. Then, each U curve gets a tiny transistor, similar to the bottom of their V-shaped devices.<\/p>\n

With the combing method, Lieber and his team can complete hundreds of nanowire devices in the same amount of time they used to make just a couple. \u201cBecause they\u2019re very well-aligned, they\u2019re very easy to control,\u201d Zhang said.<\/p>\n

So far, Zhang and her colleagues have used the U-shaped nanoscale devices to record intracellular signals in both neural and cardiac cells in cultures. Coated with a substance that mimics the feel of a cell membrane, the nanowires can cross this barrier with minimal effort or damage to the cell. And they can record intracellular chatter with the same level of precision as their biggest competitor: patch clamp electrodes.<\/p>\n\r\n

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