Brazilian researchers have contributed to this field's efforts by creating an electrochemical immuno-sensor that identifies antibodies against the virus
India is recording low COVID-19 cases but the virus is still around and evolving. Experts have warned that the cases may spur again after some time soon. Surveillance remains fundamental to understanding the evolution of the virus, the risk factors for severe disease and the impact of vaccination and public health and social measures. To improve the arsenal, Brazilian researchers have contributed to this field's efforts by creating an electrochemical immuno-sensor that identifies antibodies against the virus. The innovation is described in an article published in the journal ACS Biomaterials Science and Engineering.
In search of a novel diagnostic method, the group opted for a material frequently used in metallurgy - zinc oxide - and combined it for the first time with fluorine-doped tin oxide (FTO) glass, a conductive material used in electrodes for photovoltaics and other advanced applications.
"With this unusual combination and the addition of a biomolecule, the viral spike protein, we developed a surface capable of detecting antibodies against SARS-CoV-2. The result is displayed as an electrochemical signal captured by this surface," said chemist Wendel Alves, lead author of the article. Alves is a professor at the Center for Natural and Human Sciences, Federal University of the ABC (UFABC), Sao Paulo state.
The electrode fabricated by the researchers detected COVID-19 antibodies in serum in about five minutes with 88.7 per cent sensitivity and 100 per cent specificity, outperforming even the enzyme-linked immunosorbent assay (ELISA) test, the current gold-standard clinical diagnostic tool.
According to Alves, who heads UFABC's Electrochemistry and Nanostructured Materials Laboratory, prior knowledge of chemical properties such as the isoelectric point of the virus's spike protein (S), enabled the group to develop a platform for S to bind electrostatically to zinc oxide nanorods. Zinc oxide is increasingly used to fabricate biosensors because of its versatility and unique chemical, optical and electrical properties.
The device has been validated for detecting immunity induced by CoronaVac, but the group plan to extend its use to testing for the response to Pfizer's and AstraZeneca's vaccines.
One of the advantages of the electrode they developed is its flexible architecture, which means that it can easily be customized for other diagnostic and biomedical applications using different biomolecules on the zinc oxide nanorods and other target analytes.