Scientists Create Soft, Long-lasting Implant for Recording Neuron Activity
A groundbreaking development in neural research has emerged as 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., unveiled an implantable device capable of recording individual neurons' activity over extended periods.
Understanding the activity of neurons in the brain is crucial for advancing our knowledge of neural circuits, developing medical device-based therapies, and potentially creating high-resolution brain-computer interfaces. However, current implantable devices face a trade-off between the amount of high-resolution information they can capture and their longevity.
Conventional silicon implants, equipped with numerous sensors, provide extensive information but can't remain in the body for extended durations. On the other hand, smaller, flexible devices are less invasive and can last longer in the brain, but they offer only a fraction of the available neural information.
The recent achievement by an interdisciplinary team of researchers has led to the creation of a soft implantable device featuring dozens of sensors capable of stable, long-term recording of single-neuron activity in the brain. Published in Nature Nanotechnology, this development holds promise for revolutionizing the design of bioelectronics used in neural recording, stimulation, and brain-computer interfaces.
Paul Le Floch, CEO of Axoft, Inc., and first author of the paper, explained, “We have developed brain-electronics interfaces with single-cell resolution that are more biologically compliant than traditional materials." Axoft, Inc. was founded in 2021 by Le Floch, Jia Liu, Assistant Professor of Bioengineering at SEAS, and Tianyang Ye, a former graduate student and postdoctoral fellow in the Park Group at Harvard.
To overcome the challenge of balancing high-resolution data rates with device longevity, the researchers utilized fluorinated elastomers, materials known for their resilience, stability in biofluids, excellent dielectric performance, and compatibility with standard microfabrication techniques. These materials were integrated with soft microelectrodes, resulting in a probe that is 10,000 times softer than conventional flexible probes made of engineering plastics.
The team successfully demonstrated the device in vivo, recording neural information from the brains and spinal cords of mice over several months. Jia Liu, the corresponding author of the paper, emphasized the feasibility of designing novel elastomers for long-term-stable neural interfaces, potentially expanding the design possibilities for such interfaces.
The interdisciplinary research team involved experts in biology, electrical engineering, materials science, and mechanical and chemical engineering. The work was supported by the National Science Foundation through the Harvard University Materials Research Science and Engineering Center Grant No. DMR-2011754.