The COVID-19 pandemic as a predominantly respiratory disease set global priority, to develop a reliable diagnostic method that can distinguish it from other respiratory diseases with similar symptoms. Although recent researches showed that Covid-19 is more of a multi-organ and blood disease than just a respiratory one, it is still diagnosed through respiratory tract swabs and RT-PCR Kits. However, in some countries, chest CT-Scan results that met the COVID-19 criteria for hospitalized patients are also acceptable. However, diagnosing asymptomatic carriers or patients who do not have a lung infection still relays on RT-PCR test kits. Regarding these facts, these kits are a vital part of controlling the epidemic.
However, PCR kits have problems and limitations. For example, false-negative results due to incorrect sampling, improper test execution, or kits’ quality. For the best results, you need experts and high standard kits that are not available easily. Regarding these issues, some countries limited PCR tests to patients who need to be hospitalized. As a result, an infected person with mild or no symptoms whose disease has not been diagnosed can infect others, or in rare cases, leads to sudden death. If a test could confirm or rule out infection more easily and accurately, it would greatly help treat patients and control the epidemic.
Simple but Effective
In a new study published in the special issue of Biosensors and Bioelectronics journal in October 2020, a team of Iranian scientists led by Mohammad Abdolahad, from the College of Engineering, University of Tehran, described a new method to detect COVID-19 infection more efficiently and accurately. Because of his works on translating the behavior of healthy and cancerous cells into the electronic field as a new method in the diagnosis of cancer, Abdolahad won the 2019 Mustafa(pbuh) Prize in Nano Electronic Science and Technology.
In their recent work, Abdolahad and his colleagues developed a specific sensor – RDSS (ROS detector in the sputum sample) – to detect chemical substances called ROS (reactive oxygen species). As they wrote in the paper, “This is a simple electrochemical sensor to detect the ROS levels in the sputum of people candidates for COVID-19 screening due to the production of mitochondrial ROS induced by COVID virus in respiratory epithelial host cells.” Reactive oxygen species typically are chemical substances that contain oxygen. ROS is formed as a natural byproduct of oxygen metabolism in living things, But the ROS level can increase dramatically due to severe damage to cell structure.
ROS Correlation with COVID-19
Viruses are not capable of replicating themselves independently. To do that, they use a specific protein to attach to the cell surface and enter it. Then they hijack the cell reproduction mechanism and replicate themselves. As a result, the host cell dies, and before dying, it produced excessive ROS due to severe damage. It seems to be critical for any diagnostic device that how long after the virus enters the body, it can detect this excessive ROS.
After exposer to the SARS Cov-2 virus that causes COVID-19 disease, there is a three-stage disease progression. First, the viruses enter lung cells and replicate themselves, which causes the production of mitochondrial ROS. “At this stage, if the host cell is saturated with ROS, the excess enters the respiratory tract,” Abdolahad told us via an email. “In the second stage, due to resulting inflammation, some toxic ROS is produced to fight against the virus, the excess of which enters the respiratory tract again. Then, in the third stage, the immune system increases the amount of inflammation and produces a large amount of toxic ROS,” he adds.
During the third stage, called the cytokine storm, the immune system’s vigorous response to infection can cause multisystem organ failure and death. By the apropos ROS level measuring, we can detect COVID-19 infection before the life-threatening cytokine storm accrues. “The RDSS device can measure the amount of ROS that is abnormally produced in the second stage of the disease just in 30 seconds,” he says.