Sep 27 2019
Highly sensitive sensors for detecting free oxygen-containing radicals have been developed by researchers from Tomsk Polytechnic University in collaboration with partners from the Czech Republic and France. These radicals have the potential to disrupt cell function.
Sensor operation diagram. (Image credit: Tomsk Polytechnic University)
The researchers say that these sensors are a substitute to conventional analytical chemical techniques of analysis. The laboratory tests showed that the sensors have a sensitivity that is four orders of magnitude higher. This was realized using the surface plasmon resonance effect together with “traps” of organic compounds. The study outcomes have been reported in Sensors and Actuators B: Chemical.
Free radicals are reactive oxygen species that have a very strong oxidizing potential. Essentially, they are a type of by-products of the respiratory chain. The superoxide radical (O2•−) is the main free radical of such a type. Although it is not hazardous by itself, during chemical transformations, it readily penetrates into other compounds with powerful oxidizing properties. They damage nucleic acids, lipids, and proteins of cell membranes.
Therefore, in medical research, it is important to detect radicals in biological objects to timely identify incipient changes in organs, tissues and take appropriate measures. Our sensors differ from others by the action, based on the effect of surface plasmon resonance.
Olga Guselnikova, Engineer, Research School of Chemistry & Applied Biomedical Sciences, Tomsk Polytechnic University
The base of the sensors, which are an example of a hybrid material that integrates organic and inorganic elements, is a thin gold plate with a surface that is wavy. Organic compounds planted on the surface serve as traps for free radicals. The plate’s wavy surface effectively stimulates the effect of surface plasmon resonance. It renders the sensors highly sensitive because of the effect of giant Raman scattering.
The organic component is a compound with a short name TEMPO. It is a simple and affordable model compound used in other methods, but it has never been combined with plasmon-active substrates. This combination of plasmon effect and chemical characteristics of TEMPO gave us the expected effect.
Olga Guselnikova, Engineer, Research School of Chemistry & Applied Biomedical Sciences, Tomsk Polytechnic University
Going forward, the scientists plan to employ the sensors to detect halogen-free and nitrogen-containing free radicals and perform experiments closer to real biological objects.
In the Czech Republic, we are also negotiating with representatives of the food industry. After all, free radicals are markers of the fact that products, particularly meat, have deteriorated or are close to this.
Olga Guselnikova, Engineer, Research School of Chemistry & Applied Biomedical Sciences, Tomsk Polytechnic University
The research work was performed in partnership with the University of Chemistry and Technology of Prague (Czech Republic) and Aix-Marseille University (France). The study was supported by grants from the Czech Science Foundation and the TPU Competitiveness Enhancement Program.