A novel protocol for detection and quantification of SARS-CoV-2 virus based on settlement rates of clay-virus-electrolyte mixture

Abstract

Detection and quantification of a virus play a crucial role in diagnosis, determination of infection stage, and decision on treatment strategies. Further, it plays a crucial role in monitoring the disease propagation during the pandemic. A wide range of analytical methods are used to detect and quantify viruses. The currently available methods are, however, laborious, costly, and time-consuming. Also, the accuracy of many of these methods is debatable. We propose a novel method for the detection and quantification of coronavirus based on the clay–virus–electrolyte interaction using the sedimentation method. Newcastle disease virus (NDV), a Coronavirus surrogate (CS), and Infectious bronchitis virus (IBV), an avian coronavirus, were used in this study. Due to changes in inter-particle forces of clay in the presence of the virus, the sedimentation rate of the clay-electrolyte system changed. A protocol was thus developed based on the changes in the sedimentation rate to predict the presence and quantity of the given virus. The sedimentation rates were recorded by mixing the bentonite clay with the CS or IBV and 0.1 M NaCl electrolyte solution at a solid-to-liquid ratio of 1:50. The sedimentation rates were varied with different CS concentrations due to different particle-particle associations due to the sorption of virus particles on the clay surface. The proposed method was successfully validated for using the plaque assay techniques for CS virus and RT-PCR for the IBV. The proposed method is simple, cost-effective, and very useful for the detection of coronavirus and other viruses' presence and quantification. Moreover, the methodology is useful to diagnose the Newcastle disease virus (NDV), which causes infection among several avian species during avian outbreaks.