New molecules fluoresce in all colors of the rainbow

Progress in biomedical imaging with PyrAt compounds

Fluorescent molecules enable the visualization of tissue and cells and are therefore indispensable in medicine and pharmacy. A team led by Nuno Maulide and Leticia González from the Faculty of Chemistry at the University of Vienna and Harald Sitte from MedUni Vienna has developed a series of novel fluorescent molecules. These can be easily produced in a single step using a Lego-like modular system and glow in all the colors of the rainbow. The results have now been published in the journal Angewandte Chemie International Edition.

Almost two hundred years after the discovery that the alkaloid quinine fluoresces under UV light, the use of fluorescent molecules is de facto indispensable for many fields, especially medicine and pharmacy. Fluorescence microscopy has revolutionized how we can study and understand biological functions because architectures and dynamics within tissues, cells and organelles can be visualized for the first time. The design and synthesis of versatile low-weight fluorescent molecules (so-called "small molecules") and advances in fluorescence microscopy are closely linked. The continuous search for new fluorophore families with complementary properties remains an important goal.

Researchers at the University of Vienna and MedUni Vienna have now developed a new class of fluorescent molecules with extraordinary properties: "PyrAte". The discovery of PyrAt compounds, which are based on an imidazo[1,2-a]pyridinium triflate, has the potential to revolutionize imaging. The highlight: this new class of molecules can be synthesized in a single step using a Lego-like - i.e. highly modular - approach from easily accessible materials. Key features of the PyrAt compounds include the wide range of different colors that can be achieved with them.

The emission of some PyrAt compounds in the near-infrared range (at wavelengths of up to 720 nm) opens up new perspectives for research into live cell imaging. In the next step, Letizia González’s team has succeeded in predicting the wavelengths of the light emitted by the PyrAt compounds using computer-aided calculations. This tool promises to optimize future experiments and accelerate discoveries in the field.

Compatibility with living cells was investigated by Harald Sitte from MedUni Vienna. His team demonstrated their effectiveness and showed their ability to navigate within the cellular landscape, which holds the potential for unprecedented insights into cellular functions.

"This discovery of PyrAt compounds represents a major advance in our understanding of fluorescent imaging and its applications in medicine," said Iakovos Saridakis, former PhD student at the University of Vienna and first author of the paper. With their remarkable properties and promising applications, the PyrAt compounds are poised to revolutionize fluorescent imaging and drive advances in biomedical research for years to come.

Original publication in Angewandte Chemie International Edition:

PyrAtes: Modular Organic Salts with Large Stokes Shifts for Fluo-rescence Microscopy Iakovos Saridakis, Margaux Riomet, Oliver J. V. Belleza, Guilhem Coussanes, Nadja K. Singer, Nina Kastner, Yi Xiao, Elliot Smith, Veronica Tona, Aurélien de la Torre, Eric F. Lopes, Pedro A. Sánchez-Murcia, Leticia González, Harald H. Sitte, and Nuno Maulide
DOI: 10.1002/anie.202318127

Illustration :

Fig. 1 : Modular preparation of PyrAt compounds and range of accessible fluorescent colors. C: Maulide Group More content can be found in the general section Mathematics and Technology in the science magazine Rudolphina of the University of Vienna.