Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nano-thermometer takes temperature inside cells

23.08.2019

Rice University chemistry lab uses fluorescence of molecular motors to sense conditions

How do you know a cell has a fever? Take its temperature.


Rice University chemists modified BODIPY molecules to serve as nano-thermometers inside cells. The chart on the left is a compilation of fluorescent lifetime micrographs showing the molecules' response to temperature, in Celsius. At right, the structure of the molecule shows the rotor, at bottom, which is modified to restrict 360-degree rotation.

Credit: Meredith Ogle/Rice University

That's now possible thanks to research by Rice University scientists who used the light-emitting properties of particular molecules to create a fluorescent nano-thermometer.

The Rice lab of chemist Angel Martí revealed the technique in a Journal of Physical Chemistry B paper, describing how it modified a biocompatible molecular rotor known as boron dipyrromethene (BODIPY, for short) to reveal temperatures inside single cells.

The molecule is ideally suited to the task. Its fluorescence lasts only a little while inside the cell, and the duration depends heavily on changes in both temperature and the viscosity of its environment. But at high viscosity, the environment in typical cells, its fluorescence lifetime depends on temperature alone.

It means that at a specific temperature, the light turns off at a particular rate, and that can be seen with a fluorescence-lifetime imaging microscope.

Martí said colleagues at Baylor College of Medicine challenged him to develop the technology. "Everybody knows old thermometers based on the expansion of mercury, and newer ones based on digital technology," he said.

"But using those would be like trying to measure the temperature of a person with a thermometer the size of the Empire State Building."

The technique depends on the rotor. Martí and Rice graduate student and lead author Meredith Ogle constrained the rotor to go back and forth, like the flywheel in a watch, rather than letting it rotate fully.

"It pretty much wobbles," Martí said.

"What we measure is how long the molecule stays in the excited state, which depends on how fast it wobbles," he said. "If you increase the temperature, it wobbles faster, and that shortens the time it stays excited."

The effect, Martí said, is conveniently independent of the concentration of BODIPY molecules in the cell and of photobleaching, the point at which the molecule's fluorescent capabilities are destroyed.

"If the environment is a bit more viscous, the molecule will rotate slower," Martí said. "That doesn't necessarily mean it's colder or hotter, just that the viscosity of the environment is different.

"We found out that if we constrain the rotation of this motor, then at high viscosities, the internal clock -- the lifetime of this molecule -- becomes completely independent of viscosity," he said. "This is not particularly common for these kind of probes."

Martí said the technique might be useful for quantifying the effects of tumor ablation therapy, where heat is used to destroy cancer cells, or in simply measuring for the presence of cancers. "They have a higher metabolism than other cells, which means they're likely to generate more heat," he said. "We'd like to know if we can identify cancer cells by the heat they produce and differentiate them from normal cells."

###

Co-authors of the paper are Rice graduate student Ashleigh Smith McWilliams; Matthew Ware, a scientist at Celgene Co., San Diego; Steven Curley, a surgeon at Christus Mother Frances Hospital, Tyler, Texas; and Stuart Corr, an assistant professor of surgical research and director of surgical innovation and technology development at Baylor College of Medicine.

The Dunn Collaborative Research Grant Program and the Optical Imaging and Vital Microscopy Core at Baylor College of Medicine, funded by the National Institutes of Health, supported the research.

Read the abstract at https://pubs.acs.org/doi/10.1021/acs.jpcb.9b04384.

This news release can be found online at http://news.rice.edu/2019/08/22/temperatures-inside-cells-taken-by-nano-thermometer-2/

Follow Rice News and Media Relations on Twitter @RiceUNews.

Related materials:

Angel Martí Group: https://martigroup.rice.edu

Rice Department of Chemistry: https://chemistry.rice.edu

Wiess School of Natural Sciences: https://naturalsciences.rice.edu

Image for download:

https://news-network.rice.edu/news/files/2019/08/0826_TEMP-1-WEB.jpg

Rice University chemists modified BODIPY molecules to serve as nano-thermometers inside cells. The chart on the left is a compilation of fluorescent lifetime micrographs showing the molecules' response to temperature, in Celsius. At right, the structure of the molecule shows the rotor, at bottom, which is modified to restrict 360-degree rotation. (Credit: Meredith Ogle/Rice University)

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,962 undergraduates and 3,027 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 4 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance.

Mike Williams
713-348-6728
mikewilliams@rice.edu

Media Contact

Mike Williams
mikewilliams@rice.edu
713-348-6728

 @RiceUNews

http://news.rice.edu 

Mike Williams | EurekAlert!
Further information:
http://news.rice.edu/2019/08/22/temperatures-inside-cells-taken-by-nano-thermometer-2/
http://dx.doi.org/10.1021/acs.jpcb.9b04384

More articles from Life Sciences:

nachricht Happy hour for time-resolved crystallography
17.09.2019 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Too much of a good thing: overactive immune cells trigger inflammation
16.09.2019 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Happy hour for time-resolved crystallography

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.

The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.

Im Focus: Modular OLED light strips

At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.

Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...

Im Focus: Tomorrow´s coolants of choice

Scientists assess the potential of magnetic-cooling materials

Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....

Im Focus: The working of a molecular string phone

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.

This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.

Im Focus: Milestones on the Way to the Nuclear Clock

Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.

If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Society 5.0: putting humans at the heart of digitalisation

10.09.2019 | Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

AI for Laser Technology Conference: optimizing the use of lasers with artificial intelligence

29.08.2019 | Event News

 
Latest News

Novel mechanism of electron scattering in graphene-like 2D materials

17.09.2019 | Materials Sciences

Novel anti-cancer nanomedicine for efficient chemotherapy

17.09.2019 | Health and Medicine

Fungicides as an underestimated hazard for freshwater organisms

17.09.2019 | Ecology, The Environment and Conservation

VideoLinks
Science & Research
Overview of more VideoLinks >>>