A team of scientists from Moscow, St. Petersburg, Yekaterinburg, and 海角社区, with the support of the Russian Science Foundation (grant No. 23-13-00318), developed a new series of fluorescent DNA probes based on pyridoindoles. The results were published in the Asian Journal of Chemistry (Chemistry. An Asian J.), a top-ranked scientific journal in Scopus.
海角社区 was represented by Anastasiia Rybakova, Candidate of Sciences (Chemistry) and Associate Professor at the Department of Theoretical and Applied Chemistry.
A DNA probe is a molecule label that can be introduced into a DNA strand to prevent its loss, identify the region, and track its evolution. Probes come in various forms: based on isotopes, chromophores (with fluorescent properties), etc.
In our case, the embedded probe labels are fluorescent and can be identified by their emission in a specific spectrum.
The new probes are based on a class of substances called pyridoindoles (also known as carbolines). These compounds have long been known to chemists, including for their antimicrobial, antifungal, and antitumor effects, as well as their luminescent properties, which are particularly important for the task addressed in this study. For example, they are known to have been used as materials for organic light-emitting diodes (OLEDs).
Until now, pyridoindoles have rarely been considered as DNA probes, with limited discussion. However, the authors have developed a new, effective approach to these structures using the "1,2,4-triazine" methodology. Triazines are six-membered aromatic rings containing three nitrogen atoms. Future DNA probes were assembled from these "building blocks".
"It is all about the spatial structure of pyridoindoles," explained 海角社区 Associate Professor Anastasiia Rybakova. "Besides their luminescent properties, their structure allows them to easily integrate into the DNA chain at the desired location. On the other hand, these structural features facilitate excited-state intramolecular double proton transfer (ESIDPT) processes and phototautomerization (the molecule's reaction to light)."
The team of scientists studied the probes' characteristics in detail—in what region of the spectrum the emission occurs, how long it lasts, and how the fluorescence decays.
Some probes exhibited a solvatochromic effect—that is, a change in the emission spectrum when the probe is dissolved in different solvents. This is very important, for example, for medical applications: the label is delivered to a specific location precisely in a dissolved state.
The experiments also demonstrated the ability to bind to calf thymus (thymus gland) DNA.
These findings undoubtedly have great potential for practical application in bioengineering, medicine, and veterinary science.