New dye allows super-imaging of cells

April 11, 2017
Molecular structure of C-Naphox. Credit: Institute of Transformative Bio-Molecules (ITbM)

A new dye might allow researchers to view natural processes in extremely small components of living cells over a prolonged period of time; a previously unattainable feat.

Optical allows to see and distinguish between objects that are about 200 nanometres (nm) apart. In comparison, a is about 90,000 nm thick. Unfortunately, most objects of interest in biology, such as organelles in cells and proteins, are much smaller than 200 nm.

Biologists have been looking for ways to improve the resolution of microscopes, pioneering the field of . Stimulated emission depletion (STED) microscopy is one such improvement: a source of light focuses on a point of interest while the surrounding zone is kept in the dark and toned down, so to speak, using a special laser to form a background without interferences. This technique is fluorescence-based, using special dyes to tag the cells or structures of interest.

STED microscopy is very effective, allowing researchers to detect objects that are only tens of nanometres apart. However, it does come with its own set of challenges: most importantly, that the special laser used to tone down the background is, counter-intuitively, very intense. Not many dyes can withstand this intensity without losing fluorescence so quickly that only a few images can be taken, which is much too fast for the needs of researchers.

(Above) STED microscopy images of cells with C-Naphox remained stable. (Below) STED microscopy images with a commercially available compound. Credit: Institute of Transformative Bio-Molecules (ITbM)

Professor Shigehiro Yamaguchi and Professor Tetsuya Higashiyama from the Institute of Transformative Bio-Molecules at Nagoya University in Japan have developed a dye, called C-Naphox, that, thanks to a carbon-bonded structure, is very stable and does not dim even under the harsh conditions of STED microscopy. It is also non-toxic, so it can be used in live cells.

The researchers found that the dye remained stable after two hours of irradiation. When taking multiple images in succession—a key part of super-resolution microscopy as it allows researchers to follow live cells undergoing their natural processes over time—the team found that C-Naphox remained stable after five images. Even after taking 50 images, more than 80 percent of the C-Naphox signal remained. In comparison, one of the best options available commercially, a compound called Alexa 488, dimmed almost to invisibility after taking only five images. Once widely available, C-Naphox should enable prolonged recording of using STED microscopy; a previously unattainable feat.

Explore further: A new molecular tool for continuous super-resolution fluorescence microscopy

Related Stories

Background suppression for super-resolution light microscopy

February 1, 2017

Researchers of Karlsruhe Institute of Technology (KIT) have developed a new fluorescence microscopy method: STEDD (Stimulation Emission Double Depletion) nanoscopy produces images of highest resolution with suppressed background. ...

Watching molecule movements in live cells

July 24, 2013

The newly developed STED-RICS microscopy method records rapid movements of molecules in live samples. By combining raster image correlation spectroscopy (RICS) with STED fluorescence microscopy, researchers of Karlsruhe Institute ...

Recommended for you

Chemical treatment improves quantum dot lasers

October 16, 2017

One of the secrets to making tiny laser devices such as opthalmic surgery scalpels work even more efficiently is the use of tiny semiconductor particles, called quantum dots. In new research at Los Alamos National Laboratory's ...

Low-cost battery from waste graphite

October 11, 2017

Lithium ion batteries are flammable and the price of the raw material is rising. Are there alternatives? Yes: Empa and ETH Zürich researchers have discovered promising approaches as to how we might produce batteries out ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.