Dye made the DNA sensors more sensitive

(ORDO NEWS) — Russian scientists have created unique DNA sensors based on acridine yellow dye. Due to its specific interaction with DNA molecules, it will be possible to detect even small amounts of low molecular weight and difficult to detect molecules, such as antibiotics. At the same time, the often interfering stabilizers of dosage forms and proteins of the patient do not affect the accuracy of the analysis.

The results of the work, carried out with the support of a grant from the Presidential Program of the Russian Science Foundation (RSF), are published in the Sensors magazine . DNA sensors are promising systems for detecting molecules that can bind to or damage nucleic acid.

They are especially important for the detection of anticancer drugs: cytostatics that suppress the growth of tumor cells are extremely toxic not only for defective cells, but also for normal cells. In the course of treatment, it is necessary to control the content of the drug in the patient’s biological fluids so as not to cause irreparable harm to his health with a new dose of the drug.

A DNA sensor is a substrate made of a conducting material (electrode), on which modifiers and, in fact, DNA are applied. Nucleic acids can react with molecules contained in the analyzed samples, thus changing the redox properties of the modifier – so you can understand that DNA interacts with the antibiotic in the sample solution.

“When we identify large molecules like proteins, the signal will be high, but sometimes we have to work with low molecular weight compounds, which do not significantly affect the properties of the system. In such cases, it is necessary to complicate both the protocol for creating a DNA sensor and the measurement protocol , ”says Tatyana Kulikova, PhD in Chemistry, an employee of the Laboratory of Bioelectrical and Biosensor Research at Kazan Federal University.

Employees of the Kazan Federal University (Kazan) and the Ural Federal University (Yekaterinburg) proposed to apply particles of carbon black (“soot”) to a glassy carbon electrode to increase the area of ​​its working surface and an acridine yellow dye, and then DNA molecules. They used their device to determine the antibiotic doxorubicin, which is embedded between DNA strands.

dye made the DNA sensors more sensitive 1

The sensor was able to detect nanomolar concentrations of the substance, while it was not disturbed by the presence of plasma proteins and stabilizers of dosage forms, which can worsen the results of the analysis due to the occurrence of adverse reactions. The combination of acridine yellow molecules made it possible to increase the sensitivity of determining the interaction of doxorubicin with DNA.

“This was the first time we used this dye as part of a DNA sensor, and it was important to demonstrate the very fact of its work as a surface modifier. This allowed the determination of very low concentrations of doxorubicin, but at the same time did not require a complex procedure for modifying the sensor.

The system is promising, and within the framework of the project we will continue to improve it, ”sums up the project manager of the Russian Science Foundation Anna Porfirieva, PhD in Chemistry, Associate Professor of the Department of Analytical Chemistry at Kazan Federal University.


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