Research Highlights | Bioelectronics at MIT

Tiny magnetic discs offer remote brain stimulation without transgenes

Fri, 11 Oct 2024 00:00:00 +0000

Novel magnetic nanodiscs could provide a much less invasive way of stimulating parts of the brain, paving the way for stimulation therapies without implants or genetic modification, MIT researchers report.

The scientists envision that the tiny discs, which are about 250 nanometers across (about 1/500 the width of a human hair), would be injected directly into the desired location in the brain. From there, they could be activated at any time simply by applying a magnetic field outside the body. The new particles could quickly find applications in biomedical research, and eventually, after sufficient testing, might be applied to clinical uses.

The development of these nanoparticles is described in the journal Nature Nanotechnology, in a paper by Polina Anikeeva, a professor in MIT’s departments of Materials Science and Engineering and Brain and Cognitive Sciences, graduate student Ye Ji Kim, and 17 others at MIT and in Germany.

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A multifunctional tool for cognitive neuroscience

Thu, 19 Oct 2023 00:00:00 +0000

A team of researchers at MIT’s McGovern and Picower Institutes has advanced the clinical potential of a thin, flexible fiber designed to simultaneously monitor and manipulate neural activity at targeted sites in the brain. The collaborative team improved upon an earlier model of the multifunctional fiber, developed in the lab of McGovern Institute Associate Investigator Polina Anikeeva, to explore dynamic changes to neural signaling as large animals engage in a working memory task. The results appear Oct. 6 in Science Advances.

The new device, developed by Indie Garwood, who recently received her PhD in the Harvard-MIT Program in Health Sciences and Technology, includes four microelectrodes for detecting neural activity and two microfluidic channels through which drugs can be delivered. This means scientists can deliver a drug that alters neural signaling within a particular part of the brain, then monitor the consequences for local brain activity. This technology was a collaborative effort between Anikeeva, who is also the Matoula S. Salapatas Professor in Materials Science and Engineering and a professor of brain and cognitive sciences, and Picower Institute Investigators Emery Brown and Earl Miller, who jointly supervised Garwood to develop a multifunctional neurotechnology for larger and translational animal models, which are necessary to investigate the neural circuits that underlie high-level cognitive functions. With further development and testing, similar devices might one day be deployed to diagnose or treat brain disorders in human patients.

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Soft optical fibers block pain while moving and stretching with the body

Thu, 19 Oct 2023 00:00:00 +0000

Scientists have a new tool to precisely illuminate the roots of nerve pain.

Engineers at MIT have developed soft and implantable fibers that can deliver light to major nerves through the body. When these nerves are genetically manipulated to respond to light, the fibers can send pulses of light to the nerves to inhibit pain. The optical fibers are flexible and stretch with the body.

The new fibers are meant as an experimental tool that can be used by scientists to explore the causes and potential treatments for peripheral nerve disorders in animal models. Peripheral nerve pain can occur when nerves outside the brain and spinal cord are damaged, resulting in tingling, numbness, and pain in affected limbs. Peripheral neuropathy is estimated to affect more than 20 million people in the United States.

“Current devices used to study nerve disorders are made of stiff materials that constrain movement, so that we can’t really study spinal cord injury and recovery if pain is involved,” says Siyuan Rao, assistant professor of biomedical engineering at the University of Massachusetts at Amherst, who carried out part of the work as a postdoc at MIT. “Our fibers can adapt to natural motion and do their work while not limiting the motion of the subject. That can give us more precise information.”

“Now, people have a tool to study the diseases related to the peripheral nervous system, in very dynamic, natural, and unconstrained conditions,” adds Xinyue Liu PhD ’22, who is now an assistant professor at Michigan State University (MSU).

Details of their team’s new fibers are reported today (Nat. Methods) in a study appearing in Nature Methods. Rao’s and Liu’s MIT co-authors include Atharva Sahasrabudhe, a graduate student in chemistry; Xuanhe Zhao, professor of mechanical engineering and civil and environmental engineering; and Polina Anikeeva, professor of materials science and engineering, along with others at MSU, UMass-Amherst, Harvard Medical School, and the National Institutes of Health.

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Magnetic robots walk, crawl, and swim

Fri, 07 Jul 2023 00:00:00 +0000

MIT scientists have developed tiny, soft-bodied robots that can be controlled with a weak magnet. The robots, formed from rubbery magnetic spirals, can be programmed to walk, crawl, swim — all in response to a simple, easy-to-apply magnetic field.

“This is the first time this has been done, to be able to control three-dimensional locomotion of robots with a one-dimensional magnetic field,” says Professor Polina Anikeeva, whose team published an open-access paper on the magnetic robots June 3 in the journal Advanced Materials. “And because they are predominantly composed of polymer and polymers are soft, you don’t need a very large magnetic field to activate them. It’s actually a really tiny magnetic field that drives these robots,” adds Anikeeva, who is a professor of materials science and engineering and brain and cognitive sciences at MIT, a McGovern Institute for Brain Research associate investigator, as well as the associate director of MIT’s Research Laboratory of Electronics and director of MIT’s K. Lisa Yang Brain-Body Center.

The new robots are well suited to transport cargo through confined spaces and their rubber bodies are gentle on fragile environments, opening the possibility that the technology could be developed for biomedical applications. Anikeeva and her team have made their robots millimeters long, but she says the same approach could be used to produce much smaller robots.

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Unraveling connections between the brain and gut

Thu, 22 Jun 2023 00:00:00 +0000

The brain and the digestive tract are in constant communication, relaying signals that help to control feeding and other behaviors. This extensive communication network also influences our mental state and has been implicated in many neurological disorders.

MIT engineers have designed a new technology for probing those connections. Using fibers embedded with a variety of sensors, as well as light sources for optogenetic stimulation, the researchers have shown that they can control neural circuits connecting the gut and the brain, in mice.

In a new study, the researchers demonstrated that they could induce feelings of fullness or reward-seeking behavior in mice by manipulating cells of the intestine. In future work, they hope to explore some of the correlations that have been observed between digestive health and neurological conditions such as autism and Parkinson’s disease.

“The exciting thing here is that we now have technology that can drive gut function and behaviors such as feeding. More importantly, we have the ability to start accessing the crosstalk between the gut and the brain with the millisecond precision of optogenetics, and we can do it in behaving animals,” says Polina Anikeeva, the Matoula S. Salapatas Professor in Materials Science and Engineering, a professor of brain and cognitive sciences, director of the K. Lisa Yang Brain-Body Center, associate director of MIT’s Research Laboratory of Electronics, and a member of MIT’s McGovern Institute for Brain Research.

Anikeeva is the senior author of the new study, which appears today in Nature Biotechnology. The paper’s lead authors are MIT graduate student Atharva Sahasrabudhe, Duke University postdoc Laura Rupprecht, MIT postdoc Sirma Orguc, and former MIT postdoc Tural Khudiyev.

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Controlling drug activity with light

Thu, 17 Dec 2020 00:00:00 +0000

Hormones and nutrients bind to receptors on cell surfaces by a lock-and-key mechanism that triggers intracellular events linked to that specific receptor. Drugs that mimic natural molecules are widely used to control these intracellular signaling mechanisms for therapy and in research.

In a recent publication, a team led by MIT Associate Professor Polina Anikeeva, a McGovern Institute for Brain Research Associate Investigator, and Oregon Health and Science University (OHSU) Research Assistant Professor James Frank introduce a microfiber technology to deliver and activate a drug that can be induced to bind its receptor by exposure to light.

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Mechanical Way to Stimulate Neurons

Sun, 19 Jul 2020 00:00:00 +0000

In addition to responding to electrical and chemical stimuli, many of the body’s neural cells can also respond to mechanical effects, such as pressure or vibration. But these responses have been more difficult for researchers to study, because there has been no easily controllable method for inducing such mechanical stimulation of the cells. Now, researchers at MIT and elsewhere have found a new method for doing just that.

The finding might offer a step toward new kinds of therapeutic treatments, similar to electrically based neurostimulation that has been used to treat Parkinson’s disease and other conditions. Unlike those systems, which require an external wire connection, the new system would be completely contact-free after an initial injection of particles, and could be reactivated at will through an externally applied magnetic field.

The finding is reported in the journal ACS Nano, in a paper by former MIT postdoc Danijela Gregurec, Alexander Senko PhD ’19, Associate Professor Polina Anikeeva, and nine others at MIT, at Boston’s Brigham and Women’s Hospital, and in Spain.

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Gaseous Messenger Molecule

Mon, 06 Jul 2020 00:00:00 +0000

Nitric oxide is an important signaling molecule in the body, with a role in building nervous system connections that contribute to learning and memory. It also functions as a messenger in the cardiovascular and immune systems.

But it has been difficult for researchers to study exactly what its role is in these systems and how it functions. Because it is a gas, there has been no practical way to direct it to specific individual cells in order to observe its effects. Now, a team of scientists and engineers at MIT and elsewhere has found a way of generating the gas at precisely targeted locations inside the body, potentially opening new lines of research on this essential molecule’s effects.

The findings are reported today in the journal Nature Nanotechnology, in a paper by MIT professors Polina Anikeeva, Karthish Manthiram, and Yoel Fink; graduate student Jimin Park; postdoc Kyoungsuk Jin; and 10 others at MIT and in Taiwan, Japan, and Israel.

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Hormone Release

Fri, 10 Apr 2020 00:00:00 +0000

Abnormal levels of stress hormones such as adrenaline and cortisol are linked to a variety of mental health disorders, including depression and PTSD. MIT researchers, including the Anikeeva group, have now devised a way to remotely control the release of these hormones from the adrenal gland using magnetic nanoparticles.

To achieve control over hormone release, Dekel Rosenfeld, an MIT-Technion postdoc in Professor Anikeeva’s group, has developed specialized magnetic nanoparticles that can be injected into the adrenal gland. When exposed to a weak magnetic field, the particles heat up slightly, activating heat-responsive channels that trigger hormone release. This technique can be used to stimulate an organ deep in the body with minimal invasiveness.

The researchers now plan to use this approach to study how hormone release affects PTSD and other disorders, and they say that eventually it could be adapted for treating such disorders. This method would offer a much less invasive alternative to potential treatments that involve implanting a medical device to electrically stimulate hormone release, which is not feasible in organs such as the adrenal glands that are soft and highly vascularized.

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Artificial Muscles

Thu, 11 Jul 2019 00:00:00 +0000

MIT researchers, including professors Polina Anikeeva, Yoel Fink, and Cem Tasan, have developed a new fiber-based system that could be used as artificial muscles for robots, prosthetic limbs, or other mechanical and biomedical applications. Inspired by cucumber plants, which use their tightly-coiled tendrils to pull the plants upwards, this system utilizes a heat-activated coiling-and-pulling mechanism. Two materials that have different rates of thermal expansion are joined, causing the resulting fiber to form a tight coil with a surprisingly strong pulling force when even a small increase in temperature is applied. This process of contracting and expanding was shown in testing to maintain its strength even after repeating 10,000 times.

These fibers can span a wide range of sizes, and can easily be manufactured in batches up to hundreds of meters long. They are extremely lightweight and can respond quickly. Such fibers could be useful as actuators in robotic arms, legs, or grippers, as well as in prosthetic limbs, although postdoc Mehmet Kanik says that the possibilities for materials of this type are virtually limitless.

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