Newswise – The SARS-CoV-2 virus continues to cause dramatic loss of human life around the world, posing an unprecedented challenge for society, public health and the economy to overcome. Currently, SARS-CoV-2 can be diagnosed in two different ways: i) antigenic tests (point-of-care, POC) and ii) molecular tests (nucleic acid, RNA or PCR-polymerase chain reaction). Antigen tests can detect parts of SARS-CoV-2 proteins, called antigens, via a nasopharyngeal or nasal swab sampling method. The main advantages of the POC test include high specificity, rapid response (less than an hour) and portability, without the need for fixed laboratory facilities. On the other hand, in a molecular diagnostic test, reverse transcriptase polymerase chain reaction (RT-PCR) is developed, also known as nucleic acid amplification method, which requires expensive laboratory equipment, hours of analysis and special staff.
Despite the great efforts of the scientific community for the development of diagnostic tools and the achievement of high specificity and sensitivity of molecular tests, the concern regarding the control and detection of SARS-CoV-2 remains. .
Ural Federal University scientist Prof. Panagiotis Tsiakaras, along with colleagues from international research groups, focused on examining materials used for the design and development of electrochemical biosensors for the detection of SARS-CoV-2, highlighting the important role that electrochemistry could play in controlling COVID disease. This type of biosensors could be an effective virus diagnostic tool of high sensitivity, specificity, low cost, rapid response, requiring no special personnel and offering the advantage of portability. The document was published in the Journal of Electroanalytical Chemistry.
To date, two main groups of materials have been explored in depth as transducer electrodes: i) those based on Au (gold) and ii) those based on carbon or graphene. Both feature faster response time (in seconds) as well as higher accuracy than current detection methods, and most of them have higher sensitivity as well. Plus, many of them have the option of being portable and miniaturized.
By comparing the two groups of materials above, the researchers concluded that those based on carbon or graphene can compete with Au-based electrodes, as they have similar or better operational characteristics, also offering the advantage of ‘a lower cost.
In the current review, scientists recognize that in the case of Au-based electrodes, Au was mainly used in the form of nanoparticles on an alternative support (polymer-based or otherwise) or supported on oxide. of reduced graphene before being deposited on the base support. Platform. The inclusion of r-GO (reduced graphene oxide) in Au nanoparticles dramatically improves the characteristics of the SARS-CoV-2 sensor as it primarily widens the detection area that the virus binds to.
In the case of electrodes based on carbon or graphene, surface functionalization constitutes the main strategy which has been followed. In particular, graphene and its derivatives, which are considered to be the most promising materials, do not contain chemically reactive functional groups that could help immobilize analyte biomolecules. Thus, its surface or structural alteration has been studied by: i) doping graphene with another (bio) element, or ii) creating structural defects, or iii) being used as is to modify screen-printed carbon electrodes .
Among the detection techniques applied, electrochemical impedance spectroscopy, amperometry and pulse differential voltammetry were the most used. Meanwhile, in the case of the amperometric technique, there is concern about the current “real” response of the sensor when in an environment with high virus concentrations, as scattering phenomena may prevail.
Electrochemical impedance spectroscopy, square wave voltammetry, and differential pulse voltammetry detection techniques are more sensitive and reliable, especially for very low concentration values ââof the target analyte. However, to acquire the “real” load, the optimal operating conditions are set each time (Hz or no voltage, or scan rate, etc.) depending on the virus concentration.
Concluding their review, Prof. Panagiotis Tsiakaras and colleagues report that: among the electrode materials explored, Au and carbon or graphene-based electrodes are the two main groups of materials, while electrochemical biosensors based on nanomaterials could allow rapid and precise analysis. , and at no particular cost, virus detection. However, as they indicate, there is a need for further research to be done in terms of various nanomaterials and new synthetic strategies in order for SARS-CoV-2 biosensors to be commercialized.
Dr Panagiotis Tsiakaras is Professor and Head of the Department of Mechanical Engineering at the Faculty of Engineering at the University of Thessaly (Volos-Greece). He is also a member of the Laboratory of Materials and Devices for Clean Energy, Department of Electrochemical Process Technology, Ural Federal University, and Supervisor of the Laboratory of Electrochemical Devices Based on Solid Oxide Proton Electrolytes, Institute of Electrochemistry at high temperature (RAS), (Ekaterinburg-Russian Federation).
Research interests: Catalytic and electrocatalytic processes; Solid state electrochemistry; Electrochemical devices for the conversion and storage of energy; Low, medium and high temperature fuel cells; Direct alcohol fuel cells for power generation.
P. Tsiakaras is a co-author of over 300 scientific papers, books and patents, with around 14,000 citations and a Hirsch index = 62 (based on the Google Scholar database).