Researchers develop implantable device capable of recording a collection of individual neurons for months

Recording the activity of large populations of single neurons in the brain over long periods of time is crucial for deepening our understanding of neural circuits, for enabling new medical device-based therapies and, in the future, for interfaces brain-computer requiring high resolution. electrophysiological information.

But today there is a trade-off between the amount of high-resolution information an implanted device can measure and the length of time it can maintain recording or stimulation performance. Rigid silicone implants, equipped with numerous sensors, can collect a lot of information but cannot stay in the body for very long. Smaller, flexible devices are less intrusive and can last longer in the brain, but provide only a fraction of the neural information available.

Recently, an interdisciplinary team of researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with the University of Texas at Austin, MIT and Axoft, Inc., developed a flexible implantable device with dozens of sensors. which can record the activity of a single neuron in the brain stably for months.

The research was published in Natural nanotechnology.

“We have developed brain-electronic interfaces with single-cell resolution that are more biologically compliant than traditional materials,” said Paul Le Floch, first author of the paper and former graduate student in the lab of Jia Liu, assistant professor of bio -engineering at SEAS. . “This work has the potential to revolutionize the design of bioelectronics for neuronal recording and stimulation, as well as brain-computer interfaces.”

Le Floch is currently CEO of Axoft, Inc, a company founded in 2021 by Le Floch, Liu and Tianyang Ye, a former graduate student and postdoctoral fellow at the Park Group at Harvard. Harvard’s Office of Technology Development protected the intellectual property associated with this research and licensed the technology to Axoft for further development.

To overcome the tradeoff between high-resolution data throughput and longevity, researchers turned to a group of materials called fluoroelastomers. Fluorinated materials, such as Teflon, are resilient, stable in biofluids, exhibit excellent long-term dielectric performance, and are compatible with standard microfabrication techniques.

Researchers integrated these fluorinated dielectric elastomers with stacks of flexible microelectrodes (64 sensors in total) to develop a long-lasting probe that is 10,000 times softer than conventional flexible probes made from engineering plastics, such as polyimide or parylene C.

The team demonstrated the device in vivorecording neuronal information from the brain and spinal cord of mice over several months.

“Our research highlights that by carefully engineering various factors, it is possible to design new elastomers for long-term stable neuronal interfaces,” said Liu, corresponding author of the paper. “This study could expand the range of design possibilities for neural interfaces.”

The interdisciplinary research team also included SEAS professors Katia Bertoldi, Boris Kozinsky and Zhigang Suo.

“The design of new neural probes and interfaces is a very interdisciplinary problem that requires expertise in biology, electrical engineering, materials science, mechanical and chemical engineering,” said Le Floch.

The research was co-authored by Siyuan Zhao, Ren Liu, Nicola Molinari, Eder Medina, Hao Shen, Zheliang Wang, Junsoo Kim, Hao Sheng, Sebastian Partarrieu, Wenbo Wang, Chanan Sessler, Guogao Zhang, Hyunsu Park, Xian Gong, Andrew. Spencer, Jongha Lee, Tianyang Ye, Xin Tang, Xiao Wang and Nanshu Lu.