Fluorescent dyes are like special markers that help researchers see things that are not visible. They are used in medical imaging and to help kill diseased cells. However, these dyes often fade in harsh acidic environments. They are like highlighters that lose color in water. Researchers use them to see chemical changes and cellular structures.

The problem with these dyes is that they are not strong enough for use in environments with strong acids. This limits their use in places like fuel cells and filtration systems. There are dyes called BODIPYs that are highly valued for their bright fluorescence. However, they have a weakness called deboronation, where strong acids remove the central boron atom, making them lose their glow.

Researchers at Hokkaido University have created a new type of fluorescent dye that can survive in very harsh acidic conditions. The study was published in Nature Communications by a team led by Yasuhide Inokuma.

Previous attempts to make BODIPYs more resistant to acid focused on changing the chemical groups attached to boron. However, these dyes only survived in mildly acidic environments.

The Hokkaido team took a different approach by changing the molecular framework around the boron center. They drew inspiration from a ring-shaped molecular structure that binds boron atoms tightly. They built a rigid macrocycle around the fluorescent core, making it more resistant to acid.

The new design made the dye much more resilient. When placed in a very strong acid, the dye maintained 90 percent of its fluorescence after 12 hours.

Conventional BODIPYs lost all fluorescence within one hour in a milder acid.

The new dye also survived high temperatures and resisted photodegradation, outperforming other dyes.

The new design introduced a built-in on/off switch that uses acid to turn on the fluorescence. Under neutral conditions, the dye is dark, but when exposed to strong acid, it starts to glow.

This acid-activated switching was useful for imaging materials that were difficult to analyze with fluorescence. The new dye was able to make these materials glow brightly.

The dye was also able to switch on and off repeatedly in other materials, showing its practical durability.

The researcher hopes this work will inspire the development of fluorescent molecules for extreme environments.

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Source: Springer Nature Research Communities