A team of researchers led by Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has introduced a soft implantable device capable of recording single-neuron activity in the brain over extended periods. The breakthrough, detailed in a paper titled "3D spatiotemporally scalable in vivo neural probes based on fluorinated elastomers", represents a major step forward in the quest for high-resolution, long-term neural recording.
One of the enduring challenges in neural recording technology has been the tradeoff between high-resolution data collection and the longevity of implanted devices. Rigid silicon implants can gather vast amounts of information but struggle to remain in the body for extended durations. On the other hand, smaller, flexible devices offer increased durability but provide only a fraction of the neural data.
Soft Implant Design: Striking the Balance
Led by Paul Le Floch, former graduate student in the lab of Jia Liu, Assistant Professor of Bioengineering at SEAS, the interdisciplinary team has devised a soft implantable device equipped with dozens of sensors. This innovative design achieves stable recording of single-neuron activity for months, overcoming the traditional tradeoff.
"We have developed brain-electronics interfaces with single-cell resolution that are more biologically compliant than traditional materials. This work has the potential to revolutionize the design of bioelectronics for neural recording and stimulation, and for brain-computer interfaces," explained Le Floch, now the CEO of Axoft, Inc.
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Fluorinated Elastomers: The Key to Long-Term Stability
To surmount the tradeoff challenge, the researchers turned to fluorinated elastomers, materials known for their resilience, stability in biofluids, excellent long-term dielectric performance, and compatibility with microfabrication techniques. By integrating these materials with stacks of soft microelectrodes-64 sensors in total-the team created a probe that is 10,000 times softer than conventional flexible probes made of engineering plastics.
The efficacy of the soft implantable device was demonstrated in vivo, as the researchers recorded neural information from the brains and spinal cords of mice over several months. This success marks a significant advancement in achieving long-term stable neural interfaces.
Liu emphasized that the "study could expand the range of design possibilities for neural interfaces." The paper, highlights the interdisciplinary collaboration involving experts in biology, electrical engineering, materials science, mechanical, and chemical engineering.
Founded in 2021 by Le Floch, Liu, and Tianyang Ye, Axoft, Inc. has acquired the intellectual property associated with this groundbreaking research. Harvard's Office of Technology Development has licensed the technology to Axoft for further development, marking a crucial step toward potential real-world applications of this revolutionary soft implantable device. The company aims to drive innovation in the field of neurotechnology, paving the way for transformative advancements in brain-computer interfaces and medical device-based therapies.
