2 days ago
Cyborg tadpoles ‘hold clues to origin of autism'
Cyborg tadpoles with electrodes grown into their brains have been created by Harvard scientists to help study autism and schizophrenia.
Tiny flexible electrodes were implanted into tadpole embryos when they were days old, allowing them to completely embed into the central nervous system as the amphibians grew.
It is the first time that researchers have shown it is possible to create a device that integrates seamlessly into the brain while it develops.
Usually, scientists implant metal electrodes into mature brains to monitor brain cell activity, but by then, the critical early stages of development are over and the process often causes some neuronal damage.
Neurological conditions such as autism, bipolar disorder and schizophrenia are thought to be 'baked in' to the brain early on, so being able to watch the brain developing could offer vital clues into why they develop.
'Autism, bipolar disorder, schizophrenia – these all could happen at early developmental stages,' said Dr Jia Liu, assistant professor of bioengineering at Harvard School of Engineering and Applied Sciences.
'There is just no ability currently to measure neural activity during early neural development. Our technology will really enable an uncharted area.
'If we can fully leverage the natural development process, we will have the ability to implant a lot of sensors across the 3D brain non-invasively, and at the same time, monitor how brain activity gradually evolves over time. No one has ever done this before.'
To create the cyborg tadpoles, scientists used soft, stretchy implantable ribbons containing dozens of sensors capable of recording the activity of single neurons in the brain.
The probes were developed at Harvard and are made from a material known as a 'fluorinated elastomer', similar to Teflon, which can live stably in the brain for several months.
It is as soft as biological tissue but can be engineered into highly resilient electronic components that can house multiple sensors for recording brain activity.
The ribbons were implanted on an area of the embryo called the 'neural plate', which is the earliest stage of the nervous system. As the embryo develops, the plate bends into a u-shape, taking the ribbon probes inside.
By the time the neural plate has grown into the neural tube – the basis of the brain and central nervous system – the electronics are completely embedded inside, where they can give a read-out of how the neurons are firing and communicating with each other.
Researchers say the device can record electrical activity from single brain cells with millisecond precision, with no impact on normal tadpole embryo development or behaviour.
By integrating their stretchable device into the neural plate, the researchers showed they could continuously monitor brain activity during each embryonic stage.
'These so-called cyborg tadpoles offer a glimpse into a future in which profound mysteries of the brain could be illuminated, and diseases that manifest in early development could be understood, treated or cured,' Harvard said in a press notice about the new technology.
The research is published in the journal Nature.
