Magnetic microparticles allow remote control of select brain cells
The ability to stimulate and or control cells in the brain could provide us with powerful new ways to understand and treat neurological disorders, and we're starting to see some very interesting ways this might be achieved. Scientists at University College London (UCL) have demonstrated in rodents a new type of "micromagnet" that can work as a miniaturized mechanical switch to turn on touch-sensitive cells, offering a new method for controlling specific regions of the brain.
There are parallels between this breakthrough and another exciting branch of research focused on careful control of cells in the body, known as optogenetics. This technique involves inserting genes into otherwise regular calls to make them sensitive to light, allowing them to be stimulated for the purposes of treating paralysis, relieving pain and restoring vision.
Although there have been success stories, such as a case when optogenetics was used for partial vision restoration in a human for the first time last year, adapting the technology for clinical use has proven difficult due to the need for genetic modification of the cells. The UCL team has come up with another way of controlling brain activity that doesn't involve such measures.
“Our new technology uses magnetic particles and magnets to remotely and precisely control brain cell activity and, importantly, does this without introducing any device or foreign gene into the brain," said lead researcher Dr Yichao Yu.
The team's magnet-centric approach involves targeting brain cells called astrocytes, which live between the brain's blood vessels and nerve cells and supply neurons with metabolic and structural support, while also regulating activity of neuronal circuits. Conveniently for the scientists, they also happen to be touch-sensitive.
“Because astrocytes are sensitive to touch, decorating them with magnetic particles means you can give the cells a tiny prod from outside the body using a magnet, and as such, control their function," said senior author, Professor Mark Lythgoe. "This ability to remotely control astrocytes provides a new tool for understanding their function and may have the potential to treat brain and mood disorders, including depression."
The team has dubbed its technology “magnetomechanical stimulation,” (MMS) and it involves tiny magnetic particles that have been coated with an antibody. This sees them bind selectively to astrocytes, something demonstrated through injections into targeted brain regions in rats, and then switched on by placing a magnetic device near the head, outside the body. This in turn activated a range of signaling pathways said to regulate a wide variety of brain functions.
“The ability to control brain astrocytes using a magnetic field gives the researchers a new tool to study the function of these cells in health and disease that may be important for future development of novel and effective treatments for some common neurological disorders, such as epilepsy and stroke," said Lythgoe.
Furthermore, the magnetic particles also light up on MRI scans, which enables the team to trace their location in the brain very precisely. This, paired with the non-invasive nature of the technology, has the scientists highly optimistic about the possibilities.
“We are very excited about this technology because of its clinical potential," said Lythgoe. "In contrast to existing methods, MMS takes advantage of the remarkable sensitivity to touch of certain brain cells, therefore neither genetic modification nor device implantation is needed."
The research was published in the journal Advanced Science.
Source: University College London