Scientists Can Now Inject Electronics into the Brain With a Needle

Bright-field image showing the mesh electronics being injected through sub-100 micrometer inner diameter glass needle into aqueous solution. Image Credit: Lieber Research Group, Harvard University

The ability to manipulate objects on a very small scale through nanotechnology has opened the door to new ways of monitoring what’s going on with our bodies. The brain is no exception, and now researchers have created microscopic, flexible electronics that can be implanted into parts of the brain using nothing but a small needle. These electronic probes could vastly change how we monitor brain activity and treat ailments.

The new electronics, reported this week in Nature Nanotechnology, come from Charles Lieber and his colleagues. Lieber, a professor of chemistry at Harvard’s School of Engineering and Applied Sciences, says many existing microscopic electronic devices come in the form of chips built to work on a flat surface. “That’s not really enough when you’re looking at most biological systems because they’re 3D,” he says. “Even if the surface can be bent, it’s still more or less a two-dimensional structure.”

While doctors can already surgically implant electronics into the brain, such as in cases of Parkinson’s Disease where deep brain stimulation is used to treat tremors, many of these devices are quite large. Implanting them is an invasive surgical procedure, and they cause an immune response from the body, which sees the devices as foreign.

Leiber wanted to create an electronic device small enough and flexible enough to be implanted inside the body swiftly and silently, without eliciting a negative response. For inspiration, he looked to bioscaffolds, lab-grown 3D materials often implanted in damaged tissue to serve as a sort of support structure for the development of new, healthy tissue. Scaffolds are used in procedures like bone and cartilage regeneration. Lieber set out to create a microscopic bioscaffold made from electronics.

The result is a tiny mesh of electrodes that be can be implanted in living tissue by a tiny needle just 0.1 mm in diameter. The mesh is incredibly thin and up to a million times more pliable than existing flexible electronic probes. “The flexibility is really approaching that of the tissue,” Lieber says, “so it starts to look structurally like a neural network and have mechanical property of dense neural tissue.”

The team rolled up the electronics within a needle and then injected them into the hippocampuses of lab mice, where they unfolded to their original shape within an hour without sustaining any damage. They then were able to monitor, live, the neural activity of the mice. Five weeks later, the mice's immune systems showed no response to the foreign objects.

Lieber also implanted the flexible electronics into mice brain ventricles—the fluid-filled spaces—and was surprised to see the neurons attach themselves to the mesh and multiply. “These neurons were migrating onto our mesh electronic scaffold,” he says. “They were very happy and starting to proliferate.”

How might these tiny electric probes be used in the future? They could help improve procedures in stroke patients where stem cells are implanted in the brain to repair damaged tissue. “The cells do need some support to develop well,” Lieber says. His electronics could provide that initial support and then monitor the progress. Or, imagine if you could skip invasive heart surgery and instead just implant electronics with the prick of a needle.

Lieber says a lot more research is needed to understand all the potential applications. “I think a good sign of a research area is there are a lot more questions that you can get excited about than you have the time or resources to answer,” he says. “Can we wire things up the way biology does? If we can do that then we are going to be able to measure things that we couldn’t before and improve therapeutic care in a dramatic fashion.”

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More Studies See Links Between Alzheimer's and Herpes
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Although it was discovered in 1906, Alzheimer’s disease didn’t receive significant research attention until the 1970s. In 1984, scientists identified the plaque-like buildup of amyloid beta proteins in brain tissue that causes nerve damage and can lead to symptoms like memory loss, personality changes, and physical debility.

Now, researchers are learning why amyloid beta tends to collect in brain tissue like barnacles on a ship. It might not be rallying expressly to cause damage, but to protect the brain from another invader: the herpes simplex virus.

As The Atlantic recently noted, a number of studies have strengthened the notion that amyloid beta activity is working in response to herpes, the virus that travels along nerve pathways and typically causes cold sores around the mouth (HSV-1) or genitals (HSV-2). In a study involving mice, those engineered to produce more amyloid beta were more resistant to the herpes virus than those who were not.

But when too much amyloid beta is produced to combat the virus, the proteins can affect the brain’s neurons. And while herpes tends to target specific pathways in the body that result in external sores, it’s possible that the virus might act differently in an older population that is susceptible to more widespread infection. Roughly half of adults under age 50 in the U.S. are infected with HSV-1 and 12 percent with HSV-2, which suggests that a large swath of the population could be vulnerable to Alzheimer's disease. Two other strains of the virus, HHV-6A and HHV-7, have also been found to be more common in the brains of deceased Alzheimer’s patients than in the general population.

More research will be needed to further understand the possible relationship between the two. If more findings support the theory, then it’s possible that antiviral drugs or vaccines targeting herpes might also reduce the chances of amyloid beta buildup.

[h/t Atlantic]

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Heatwaves Can Affect Your Ability to Think Clearly and Make Decisions
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Dehydration and body odor aren't the only things to hate about oppressive heat. According to new research reported by The Guardian, living through a heatwave without relief hampers your ability to think quickly and clearly.

For their study, published recently in PLOS Medicine, researchers at the Harvard T.H. Chan School of Public Health tested the mental performance of 44 students during a heatwave in Boston in 2016. Roughly half the students were living in newer dorm buildings with central AC, with the other half living in older dorms without it.

Over 12 days, researchers had participants take cognition tests on their phones immediately after waking up. The students living without AC took about 13 percent longer to respond to the questions and their answers were about 13 percent less accurate.

The results indicate that even if high temperatures don't pose an immediate threat to someone's health, they can impair them in other ways. “Most of the research on the health effects of heat has been done in vulnerable populations, such as the elderly, creating the perception that the general population is not at risk from heat waves,” Jose Guillermo Cedeño-Laurent, research fellow at Harvard Chan School and lead author of the study, said in a statement. “Knowing what the risks are across different populations is critical considering that in many cities, such as Boston, the number of heat waves is projected to increase due to climate change.”

Summers are gradually becoming hotter and longer in Boston—a trend that can be observed throughout most of the rest of the world thanks to the rising temperatures caused by human activity. In regions with historically cold winters, like New England, many buildings, including Harvard's oldest dorms, are built to retain heat, which can extend the negative effects of a heat wave even as the weather outside starts to cool. If temperatures continue to rise, we'll have to make a greater effort to keep people cool indoors, where American adults spend 90 percent of their time.

Our thinking isn't the only thing that suffers in the stifling heat. A study published last year found that hot weather does indeed make you crankier—which may not be as bad as bombing a test, but it's not exactly not fun for the people around you.

[h/t The Guardian]

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