Scientists have developed cyber-embryos with ultra-soft neural sensors to monitor brain development

Researchers at Harvard University have created a new type of flexible electronics that can grow along with the developing brain of an embryo and record the activity of neurons at all stages of formation without damaging tissues. The device is an ultra-soft electronic grid embedded in the brains of frog, axolotl and mouse embryos. Sensors are integrated into brain tissue at an early stage — when it is still a flat cell layer — and form a three-dimensional structure as the organs grow.

The technology is the first to record neural activity on a millisecond scale over the entire period of embryonic development. The mesh thickness is less than 1 micrometer. The flexible sensors are made of fluorinated elastomers that can stretch and adapt to the dynamics of growing tissue, unlike previous prototypes created in 2015, which caused damage when embedded.

Tests have shown high efficiency of the technology. In tadpoles, frogs, and axolotls, sensors recorded neural impulses in different areas of the brain without disrupting behavioral responses. The animals showed habitual avoidant behavior, reacting to approaching objects. Similar results were obtained when testing on mice and newborn rats — the devices worked stably and without signs of stress in experimental subjects.

These experiments allowed scientists to track how the nature of neural activity changes with the development of the brain. In the early stages, slow synchronous signals were recorded covering the entire brain, and as the structure was formed, activity became local, fast, and diverse. Observations open up new opportunities not only for basic neuroscience, but also for improving machine learning algorithms.

Of particular interest were the results of working with axolotls. In amphibians with the ability to regenerate the nervous system, when the tail was damaged, there was a sharp increase in neural activity, reminiscent of the early stages of brain development. This observation may have implications for future research in regenerative medicine.

The project leader, Associate Professor of bioengineering at Harvard Jia Liu, stressed that the work is not related to experiments on human embryos and does not provide for them in the future. The main focus is on studying the processes of neuro-development and creating technologies that can be useful for medicine in the future.