UV-induced and silver nanoparticles-mediated formation of reactive oxygen species and interactions with guanosine monophosphate and dsDNA

Authors: Katarína Nemčeková 1    Jozef Sochr 1    Ján Labuda 1   
1 Institute of Analytical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava   
Year: 2020
Section: Utilization of instrumental methods in the analysis of biologically important substances
Abstract No.: 2016
ISBN: 978-80-972360-6-9

Silver nanoparticles (AgNPs) as an attractive nano-scale-based material possessing countless beneficial properties have been exponentially evolving in pharmaceutical, medical, commercial and industrial applications [1]. Such excessive use of AgNPs may lead to their accumulation in environment. This hypothesis has brought the increasing number of concerns and papers about the biological and health effects on an abnormal human exposure to AgNPs [2]. According to the report of World Health Organization in 2012, current evidence of AgNPs risk is not conclusive because of their complexity in shape, size and chemical modification resulting from different fabrication mechanisms [3]. Due to their nano-dimensions they are able to penetrate to human cells and initiate many structural changes of biological active molecules. After AgNPs being exposed to UV-C irradiation, the formation of oxygen radicals (known as reactive oxygen species, ROS) may occur. This mechanism leads to the oxidative stress of biomolecules which means they undergo various irreversible chemical changes in their structure [4].

The most common methods of DNA damage detection are comet and micronucleus assay as well as genotoxicity tests which are time, money and reagent consuming. For this reason, the development of new (bio)analytical methods for AgNPs toxicity assessment is extremely profitable. Here we present spectrophotometric analysis of the UV induced and silver nanoparticles mediated ROS formation. In the presence of guanosine monophosphate (GMP) or dsDNA in solution, the ROS production is strongly limited due to AgNPs-nucleobases binding interactions as well as ROS trapping by GMP and dsDNA leading to structural damage of DNA. Since it is well known, nucleobases and nucleic acids are electroactive biomolecules being involved in redox reaction mechanisms, we have developed an electrochemical assay for the detection of AgNPs-DNA interactions based on use of the DNA biosensor represented by an electrode with surface attached DNA. For these purposes, cyclic and differential pulse voltammetry was used to optimize individual parameters of the DNA immobilization process and to achieve reproducible nucleobases signals. The interactions between AgNPs and DNA were studied using the voltammetric detection techniques.

Both analyses showed the interaction between AgNPs and biomolecules via blocking the nucleobases from their oxidation and limiting the generation of ROS induced by AgNPs.

This work was supported by the STU Grant scheme for Support of Young Researchers: Detection of potential DNA degradation induced by oxygen radicals generated by photosensitive nanomaterials.
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