Eavesdropping on the pH levels inside the brain

December 23, 2020

Researchers at Tohoku University have developed the first all-in-one miniature pH probe for real-time investigations of intrinsic extracellular pH dynamics in the deep brain structures.

In our brain, over billions of dedicated workers --neurons and glial cells --form complex and efficient networks that constantly communicate with each other via subtle chemical signals to govern our behavioral output.

The brain chemistry is the fundamental language among brain cells. In our healthy brains, the chemistry stays relatively neutral and must constantly regulate the acid-alkaline fluctuations; otherwise it can lead to chronic brain disorders such as mental illness, glioma and seizures. Correlating in brain pH fluctuations with brain signaling and functions, therefore, provides a clearer understanding of the influence of pH on how our brain operates and how it malfunctions in a diseased state.

However, despite recent technical progression in electrical recordings of the brain and chemical monitoring technologies, limitations remain in measuring the chemical signaling, especially the pH of living organisms, i.e. in vivo.

The research team addressed these limitations by pioneering a hybrid device that fused two different technologies: a strand of thin fibers with seamless integration of electrical and optical functions and chemical sensors with measurement locations defined by light. The combination allows for in vivo spatially resolved detection of intrinsic chemical signaling inside the brain, especially the deeper regions, with high spatial, temporal and chemical resolution.

"We leveraged the thermal drawing process that is conventionally used in the telecommunication industry to fabricate fibers that integrate multiple functions, such as an optical waveguide, electrodes and chemical channels,' said Yuanyuan Guo, an assistant professor at the Frontier Research Institute of Interdisciplinary Sciences, Tohoku University.

Collaboration with professor Tatsuo Yoshinobu from the Graduate School of Biomedical Engineering led to the coupling of an active component --a chemical sensor with light addressability --to the fiber to realize an all-in-one hybrid chemical sensing probe for in vivo detections of subtle chemical changes in the brain. The first prototype focused on pH detections.

The probe was also tested for in vivo measurements thanks to professor Hajime Mushiake from the Graduate School of Medicine. It was able to detect slight pH fluctuations in response to seizures in rats.

"The next step for our team is to improve the spatial, temporal and chemical resolution to the level pertinent to the scales of the intrinsic neuronal dynamics," added Guo. "Our technological breakthrough will advance our basic understanding of brain chemistry and its correlation with brain functions."
-end-


Tohoku University

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.