Shape-morphing brain sensor adheres to curved surfaces for ultrasound neurostimulation

Transcranial centered ultrasound, a non-invasive method to stimulate particular areas of the mind utilizing high-frequency sound waves, may very well be a promising remedy technique for a lot of neurological problems. Most notably, it may assist to deal with drug-resistant epilepsy and different circumstances related to recurrent tremors.

Researchers at Sungkyunkwan College (SKKU), the Institute for Fundamental Science (IBS) and the Korea Institute of Science and Expertise lately developed a brand new sensor that may very well be used to carry out transcranial centered ultrasound on sufferers. This sensor, launched in a paper published in Nature Electronics, adapts its form and may intently adhere to cortical surfaces, permitting customers to file neural alerts and stimulate particular mind areas through low depth ultrasound waves.

“Earlier analysis on mind sensors that contact the mind floor struggled with precisely measuring mind alerts because of the incapability to evolve tightly to the mind’s complicated folds,” Donghee Son, supervising creator for the research, informed Tech Xplore.

“This limitation made it troublesome to exactly analyze all the mind floor and precisely diagnose mind lesions. Whereas a brain sensor previously developed by Professor John A. Rogers and Professor Dae-Hyeong Kim addressed this concern to some extent as a consequence of its extraordinarily skinny kind, it nonetheless confronted challenges in attaining tight adhesion in areas with extreme curvature.”

The sensor beforehand developed by Professors Rogers and Kim was discovered to gather extra exact measurements on the mind’s floor. Regardless of its promise, this sensor introduced numerous limitations, akin to failing to stick to surfaces of the mind that had a bigger curvature, in addition to the proneness to slipping from its authentic attachment level as a consequence of micro-motions within the mind and the movement of cerebral spinal fluid (CSF).

These noticed challenges restrict its potential use in medical settings, as they cut back its skill to constantly measure mind alerts in goal areas for extended intervals of time. As a part of their research, Son and his colleagues got down to develop a brand new sensor that would overcome these limitations, adhering nicely to curved mind surfaces and thus enabling the dependable assortment of measurements for prolonged time intervals.

“The brand new sensor we developed can tightly conform to extremely curved mind areas and cling firmly to the mind tissue,” mentioned Son. “This sturdy adhesion permits for long-term and exact measurement of mind alerts from focused areas.”

The sensor developed by Son and his colleagues, dubbed ECoG, adheres securely to mind tissue with out forming any voids. This will considerably cut back the noise originating from exterior mechanical actions.

“This attribute is especially essential in enhancing the effectiveness of epilepsy remedy via low-intensity centered ultrasound (LIFU),” mentioned Son. “Whereas it’s well-known that the ultrasound will help decrease epileptic exercise, the variability in affected person circumstances and the variations between people have posed important challenges for tailoring therapies to every affected person.”

Lately, many analysis teams have been attempting to plan personalised ultrasound stimulation therapies for epilepsy and different neurological problems. To form therapies primarily based on the wants of particular person sufferers, nonetheless, they need to be capable to measure the affected person’s mind waves in real-time whereas stimulating particular mind areas.

“Typical mind surface-attached sensors struggled with this as a result of the ultrasound-induced vibrations brought on important noise, making it troublesome to observe mind waves in real-time,” mentioned Son.

“This limitation was a significant impediment in creating personalised remedy methods. Our sensor drastically reduces noise, enabling profitable remedy of epilepsy via personalised ultrasound stimulation.”

The form-morphing and cortex-adhesive mind sensor developed by Son and his colleagues contains three essential layers. These embody a hydrogel-based layer that may bond with tissue each bodily and chemically, a self-healing polymer-based layer that may change its form to match the form of the floor beneath it, and a stretchable, ultrathin layer containing gold electrodes and interconnects.

“When the sensor is utilized to the mind floor, the hydrogel layer undergoes a gelation course of, initiating an instantaneous, sturdy attachment to the mind tissue,” defined Son.

“Following this, the self-healing polymer substrate begins to deform, conforming to the mind’s curvature, rising the contact space between the sensor and the tissue over time. As soon as the sensor has absolutely adhered to the contours of the mind, it is able to function.”

The sensor developed by this analysis workforce has a number of benefits over different mind sensors launched lately. Firstly, it may well connect to mind tissue securely whereas additionally adapting its form to suit tightly onto mind surfaces, no matter their degree of curvature.

By adapting to the form of curved surfaces, the sensor minimizes the vibrations produced by exterior ultrasound simulation. This might permit docs to exactly measure the waves of their sufferers’ brains each beneath regular circumstances and through ultrasound simulation.

“We anticipate this expertise is not going to solely be relevant in epilepsy remedy but in addition in diagnosing and treating numerous mind problems,” mentioned Son. “Essentially the most important facet of our work is the mixture of a tissue-adhesive expertise that allows the sensor to stick firmly to the floor of mind tissue and a shape-morphing expertise that permits it to evolve to the mind’s contours with out creating voids.”

Thus far, the brand new sensor developed by Son and his colleagues has been examined on residing and awake rodents. The findings collected had been extremely promising, because the workforce was capable of exactly measure mind waves and management seizures within the animals.

The researchers finally plan to scale the sensor, constructing on their design to create a high-density array. After it passes medical trials, this upgraded sensor may diagnose and deal with epilepsy or different neurological problems whereas probably paving the best way for simpler prosthetic applied sciences.

“Our mind sensor is at present geared up with 16 electrode channels, which presents an space for enchancment by way of high-resolution mind sign mapping,” added Son.

“With this in thoughts, we plan to considerably improve the variety of electrodes to allow extra detailed and high-resolution mind sign evaluation. Moreover, we goal to develop a minimally invasive methodology to implant the mind sensor on the floor of the mind, with the final word aim of making use of it in medical analysis.”

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