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Comb of a lifetime: A new method for fluorescence microscopy – Phys.org

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2-D arrangement of 44,400 light stopwatches enables scan-less fluorescence lifetime imaging. Credit: Tokushima University

Fluorescence microscopy is widely used in biochemistry and life sciences because it allows scientists to directly observe cells and certain compounds in and around them. Fluorescent molecules absorb light within a specific wavelength range and then re-emit it at the longer wavelength range. However, the major limitation of conventional fluorescence microscopy techniques is that the results are very difficult to evaluate quantitatively; fluorescence intensity is significantly affected by both experimental conditions and the concentration of the fluorescent substance. Now, a new study by scientists from Japan is set to revolutionize the field of fluorescence lifetime microscopy.

A way around the conventional problem is to focus on lifetime instead of intensity. When a fluorescent substance is irradiated with a short burst of light, the resulting fluorescence does not disappear immediately but actually “decays” over time in a way that is specific to that substance. The fluorescence lifetime microscopy technique leverages this phenomenon, which is independent of experimental conditions, to quantify fluorescent molecules and changes in their environment. However, fluorescence decay is extremely fast, and ordinary cameras cannot capture it. While a single-point photodetector can be used instead, it has to be scanned throughout the ‘s area to be able to reconstruct a complete 2-D picture from each measured point. This process involves movement of mechanical pieces, which greatly limits the speed of image capture.

In this recent study, published in Science Advances, the team of scientists developed a novel approach to acquire fluorescence lifetime images without the need for mechanical scanning. Professor Takeshi Yasui, from Institute of Post-LED Photonics (pLED), Tokushima University, Japan, who led the study, says, “Our method can be interpreted as simultaneously mapping 44,400 light-based ‘stopwatches’ over a 2-D space to measure fluorescence lifetimes—all in a single shot and without scanning.”

Comb of a lifetime: a new method for fluorescence microscopy
This new fluorescence microscopy technique will measure both fluorescence intensity and lifetime and it will not require mechanical scanning of a focal point; instead, it will produce images from all points in the sample simultaneously, enabling a more quantitative study of dynamic biological and chemical processes. Credit: Suana Science YMY

One of the main pillars of their method is the use of an optical frequency comb as the excitation light for the sample. An is essentially a composed of the sum of many discrete optical frequencies with a constant spacing in between them. The word “comb” in this context refers to how the signal looks when plotted against optical frequency: a dense cluster of equidistant spikes rising from the optical frequency axis and resembling a hair comb. Using special optical equipment, a pair of excitation frequency comb signals is decomposed into individual optical beat signals (dual-comb optical beats) with different intensity-modulation frequencies, each carrying a single modulation frequency and irradiated on the target sample. The key here is that each light beam hits the sample on a spatially distinct location, creating a one-to-one correspondence between each point on the 2-D surface of the sample (pixel) and each modulation frequency of the dual-comb optical beats.

Because of its fluorescence properties, the sample re-emits part of the captured radiation while preserving the frequency-position correspondence. The fluorescence emitted from the sample is then simply focused using a lens onto a high-speed single-point photodetector. Finally, the measured signal is mathematically transformed into the frequency domain, and the fluorescence lifetime at each “pixel” is easily calculated from the relative phase delay that exists between the excitation signal at that modulation frequency versus the one measured.

Thanks to its superior speed and , the microscopy method developed in this study will make it easier to exploit the advantages of fluorescence lifetime measurements. “Because our technique does not require scanning, a simultaneous measurement over the entire sample is guaranteed in each shot,” says Prof. Yasui, “This will be helpful in where dynamic observations of living cells are needed.” In addition to providing deeper insight into , this new approach could be used for simultaneous imaging of multiple samples for antigen testing, which is already being used for the diagnosis of COVID-19.

Perhaps most importantly, this study showcases how optical frequency combs, which were only being used as “frequency rulers,” can find a place in microscopy techniques to push the envelope in life sciences. It holds promise for the development of novel therapeutic options to treat intractable diseases and enhance life expectancy, thereby benefitting the whole of humanity.


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More information:
T. Mizuno et al. Full-field fluorescence lifetime dual-comb microscopy using spectral mapping and frequency multiplexing of dual-comb optical beats, Science Advances (2021). DOI: 10.1126/sciadv.abd2102 , advances.sciencemag.org/content/7/1/eabd2102

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Comb of a lifetime: A new method for fluorescence microscopy (2021, January 4)
retrieved 4 January 2021
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Spacewalking astronauts improve station's European lab | TheSpec.com – TheSpec.com

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CAPE CANAVERAL, Fla. – Spacewalking astronauts installed a high-speed data link outside the International Space Station’s European lab on Wednesday and tackled other improvements.

NASA’s Mike Hopkins and Victor Glover floated out early and headed straight to Columbus, one of the three high-tech labs at the orbiting outpost.

“That’s a beautiful view,” Hopkins observed as the station soared 260 miles (420 kilometres) above Kazakhstan.

The astronauts hauled with them a fancy new antenna for Columbus that will provide faster communication with European researchers via satellites and ground stations. Although they had trouble driving in some of the bolts to attach the boxy antenna, the size of a small refrigerator, it appeared to be secure and Mission Control declared success.

Danish astronaut Andreas Morgensen guided the spacewalkers from Mission Control in Houston, where controllers wore masks and were seated apart because of the pandemic.

The spacewalkers also needed to hook up power and data cables for an experiment platform for science research outside the European lab that’s been awaiting activation for almost a year.

SpaceX delivered the platform named Bartolomeo to the space station last spring. The shelf was installed with the station’s robot arm, but had to wait until Wednesday’s spacewalk to get hooked up and activated.

Airbus, which built and runs Bartolomeo, is selling space on the platform for private research projects. It’s Europe’s first commercial venture outside the station.

Hopkins and Glover will perform a second spacewalk on Monday to complete battery upgrades to the station’s solar power grid. The latest spacewalk was the third for Hopkins and first for Glover.

They are part of SpaceX’s second astronaut flight that launched in November. Their docked Dragon capsule was visible on NASA TV during the spacewalk.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

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nasa mars helicopter – Intelligent Aerospace

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WASHINGTON – NASA’s Perseverance explorer will land on the red planet on Feb. 18, but the rover won’t be the only newly arrived robotic explorer. The wheeled robot carries the Mars Helicopter Ingenuity on its belly, and NASA has posted a handy list of things to know about this mission. Although, several of the six facts seem to drive home that NASA doesn’t really know if Ingenuity is going to work. In fact, it could still be seen as a success at the Jet Propulsion Laboratory even if it crashes on its first flight, Ryan Whitwam reports for Extreme TechContinue reading original article.

The Intelligent Aerospace take:

January 27, 2021 –The Mars helicopter weighs in at four pounds on Earth (and 1.5 pounds on Mars) and has rotors that come in at four feet tip-to-tip. It is powered by a solar panel that charges Lithium-ion batteries, which allows for one 90-second flight per Martian day. In that time, it can fly up to 980 feet at an altitude up to 15 feet. It will fly autonomously.

Related: Six things to know about NASA’s Ingenuity Mars Helicopter

Related: Smiths Interconnect’s contact technology launched on NASA Mars Perseverance Rover

Related: Northrop Grumman contributes navigation system for NASA’s mars rover mission

Jamie Whitney, Associate Editor
Intelligent Aerospace

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Spacewalking astronauts venture out to improve European lab – Toronto Star

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CAPE CANAVERAL, Fla. – A pair of astronauts went spacewalking Wednesday to install a high-speed data link outside the International Space Station’s European lab.

NASA’s Mike Hopkins and Victor Glover floated out early and headed straight to Columbus, one of the three high-tech labs at the orbiting outpost.

“That’s a beautiful view,” Hopkins observed as the station soared 260 miles (420 kilometres) above Kazakhstan.

They hauled with them a fancy new antenna for Columbus that will provide faster communication with European researchers via satellites and ground stations. The boxy antenna is the size of a small refrigerator.

Danish astronaut Andreas Morgensen guided the spacewalkers from Mission Control in Houston, where controllers wore masks and were seated apart because of the pandemic.

The spacewalkers also needed to hook up power and data cables for an experiment platform for science research outside the European lab that’s been awaiting activation for almost a year.

SpaceX delivered the platform named Bartolomeo to the space station last spring. The shelf was installed with the station’s robot arm, but had to wait until Wednesday’s spacewalk to get hooked up and activated.

Airbus, which built and runs Bartolomeo, is selling space on the platform for private research projects. It’s Europe’s first commercial venture outside the station.

Hopkins and Glover will perform a second spacewalk on Monday to complete battery upgrades to the station’s solar power grid. The latest spacewalk was the third for Hopkins and first for Glover.

They are part of SpaceX’s second astronaut flight that launched in November. Their docked Dragon capsule was visible on NASA TV during the spacewalk.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

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