Rapid, low-cost, and accurate tests are still needed for epidemiological surveillance and health care services to monitor and control the spread of SARS-CoV-2. Brazilian researchers have contributed to the field’s efforts by developing an electrochemical immunosensor that detects antibodies against the virus.
The innovation is described in an article published in the journal ACS Biomaterials Science and Engineering.
In search of a new diagnostic method, the group chose a material often used in metallurgy – zinc oxide – and combined it for the first time with fluorine-doped tin oxide (FTO) glass, which is used as electrodes for photovoltaics and other applications. is the transmission material used in advanced applications.
“With this unusual combination and the addition of a biomolecule, the viral spike protein, we have developed a surface capable of detecting antibodies against SARS-CoV-2. The result is that the surface-captured electrochemical appears as a signal,” said chemist Wendell Alois. , lead author of the article. Alves is a professor at the Center for Natural and Human Sciences, Federal University of the ABC (UFABC), São Paulo State.
The electrode developed by the researchers detected COVID-19 antibodies in serum with 88.7 percent sensitivity and 100 percent specificity in about five minutes, even outperforming the enzyme-linked immunosorbent assay (ELISA) test. KA, which is the current gold standard clinical diagnostic tool.
The research was supported by the National Science and Technology Institute for Bioanalysis and FAPESP through a thematic project.
According to Alves, who heads UFABC’s Electrochemistry and Nanostructured Materials Laboratory, prior knowledge of chemical properties such as the isoelectric point of the viral spike protein (S) allowed the group to develop a platform for S enabled it to electrostatically bind zinc oxide nanorods. Zinc oxide is increasingly used to make biosensors due to its versatility and unique chemical, optical, and electrical properties.
The immunosensor is easy to fabricate and use, and its production cost is relatively low. “The group was able to develop the device thanks to their strong knowledge of new materials and zinc oxide nanorod synthesis,” Alves said. The nanorods form a film on the conductive surface of FTO, creating a favorable molecular microenvironment for S protein immobilization and a convenient method for detecting these antibodies.
The researchers will now adapt the platform to connect it to portable and mobile devices for use in the diagnosis of COVID-19 and other infectious diseases.
Analysis and future applications
A total of 107 blood serum samples were analyzed. They were divided into four groups: pre-pandemic (15), recovered from Covid-19 (47), vaccinated without previous positive disease results (25), and vaccinated after positive results. (20). The vaccine was two doses of the corona virus given four weeks apart. CoronaVac is developed by Chinese company SinoVac in collaboration with Butantan Institute (Sao Paulo State).
The authors of the article – UFABC and researchers affiliated with the Heart Institute (INCOR), which is managed by the Medical School of the University of São Paulo (FM-USP) – note that the device produces antibodies in response to both viral infections. Detects bodies. and vaccination, and shows excellent potential as a tool for monitoring seroconversion and seroprevalence. Tracking the response to vaccination is important to help public health authorities assess the effectiveness of various vaccine and immunization campaigns or programs, they emphasize.
The device has been validated to detect immunity to the coronavirus, but the group plans to expand its use to testing responses to vaccines from Pfizer and AstraZeneca.
One of the advantages of their developed electrode is its flexible architecture, which means it can be easily customized for other diagnostic and biomedical applications using different biomolecules on zinc oxide nanorods and other target analytes. Can be tailored.
“The technology is a versatile biosensing platform. As we developed it, it can be modified and customized for serological detection of other diseases of public health interest,” said Alves.
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