C. elegans temperature measured by tracking embedded nanodiamonds. Photo credit: Masazumi Fujiwara, Osaka City University
In collaboration with other international partners, a team from Osaka City University has demonstrated a reliable and precise microscope-based thermometer that works in living, microscopic animals on the basis of quantum technology and, in particular, records temperature-dependent properties of quantum spins in fluorescent nanodiamonds.
The research will be published today (September 11, 2020) in Advances in science.
The optical microscope is one of the most basic tools for analysis in biology, which uses visible light to allow the naked eye to see microscopic structures. The fluorescence microscope, an improved version of the optical microscope with various fluorescent biomarkers, is more commonly used in the modern laboratory. Recent advances in fluorescence microscopy have made it possible to map the details of a structure live and thereby obtain various physiological parameters in these structures such as pH, reactive oxygen species and temperature.
Quantum sensing is a technology that exploits the ultimate sensitivity of fragile quantum systems to the environment. High-contrast MRIs are examples of quantum spins in fluorescent diamonds and are among the most advanced quantum systems that are at the forefront of real-world applications. Applications of this technique to thermal biology were introduced seven years ago to quantify temperatures in cultured cells. However, they still had to be applied to dynamic biological systems, where heat and temperature are more actively involved in biological processes.
The research team decorated the surface of the nanodiamonds with polymer structures and injected them C. elegans Nematode worms, one of the most popular model animals in biology. They had to know the “healthy” basic temperature of the worms. Once inside, the nanodiamonds moved quickly, but the team’s novel quantum thermometry algorithm successfully tracked them and measured the temperature steadily. A fever was induced in the worms by stimulating their mitochondria with pharmacological treatment. The team’s quantum thermometer successfully observed a rise in temperature in the worms.
“It was fascinating to see how quantum technology works so well in living animals, and I never thought that tiny worms less than 1mm in size could have the temperature deviated from the norm and turn into a fever,” said Masazumi Fujiwara, lecturer in the Department of Science at Osaka City University. “Our results are an important milestone that will determine the future direction of quantum sensing as it shows how it contributes to biology.”
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Reference: September 11, 2020, Advances in science.
DOI: 10.1126 / sciadv.aba9636
The strategic scholarship of Osaka City University led this interdisciplinary and international collaboration between six institutions from four countries, including Osaka City University, Keio University, Kyoto University from Japan, Humboldt University in Berlin (Germany), Soochow University (China ) and Chapman University (USA).
This research was co-authored by Fujiwara, Sun, Dohms, Nishimura, Suto, Takezawa, Oshimi, Zhao, Sadzak, Umehara, Teki, Komatsu, Benson, Shikano, and Kage-Nakadai.
