Label-free electrochemical immunosensor employing new redox probes/porous organic polymers/graphene oxide nanocomposite towards multiplex detection of three SARS-COV2-induced storming proteins for severe COVID-19 diagnosis

Abstract

Since an outbreak of severe acute respiratory disease caused by coronavirus 2 (SARS-CoV-2) in the province of Wuhan, China, coronavirus disease 2019 (COVID-19) has tremendously evolved into a global pandemic. COVID-19 causing serious failures in organ functions is found to be involved in many groups or kinds of “cytokine storm effect” protein biomarkers resulting from the human immunological responses to the virus. The in-body abnormalities and clinical features relevant to COVID-19 exhibit a wide range and it is difficult to forecast the severity of infection in patients. Consequently, the development of a fast and highly accurate method for screening, diagnosis, monitoring, rapid identification, and isolation of COVID-19-infected patients, and monitoring its severity is urgently needed. This work aims to develop a highly sensitive multiplex label-free electrochemical immunosensor based on a porous organic polymer (POP-AQ)/graphene oxide (GO) electrode to screen and diagnose COVID-19 severity. The screen-printed carbon electrode (SPCE) consisting of three working electrodes is modified by a new POP-AQ/GO nanocomposite to enhance its specific surface area and electrochemical reactivity. The resultant platform is functionalized with three different chitosan-encapsulated redox probes (m-cresol purple (mCP), thymol blue (TMB), and polydopamine (PDA)), followed by three different antibodies, which are employed to quantitatively detect the corresponding proteins from the immunological response. This novel platform allows for the simultaneous measurement of critical illness biomarkers (IL-6, D-dimer, and ferritin), with high sensitivities and low detection limits (LODs). The biosensor displays an excellent analytical performance with wide linear dynamic ranges of 0.005–5, 2.5−100, and 2.5−100 ng mL−1, and LODs of 0.0040, 0.844, and 0.806 ng mL−1 for IL-6, D-dimer, and ferritin, respectively. Moreover, this platform reveals high reproducibility and stability, while maintaining low instrumentation complexity, and cost-effectiveness. This proposed multiplex immunosensor has excellent potential for fast COVID-19 diagnosis and severity screening in infected patients. Additionally, its versatility suggests applicability in diagnosing other diseases and emerging pathogens.