Development and clinical evaluation of commercial glucose meter coupled with nanofiber based immuno-platform for self-diagnosis of SARS-CoV-2 in saliva

Abstract

Rapid diagnostics for the diagnosis of COVID-19 are urgently needed in offices, residences, and other public places due to the new Covid epidemic stages. A portable and easy-to-use immunosensing platform was developed and evaluated for a point-of-care and self-detection of SARS-CoV-2 spike protein without the need for extraction, separation, or amplification steps using clinically isolated samples (n = 40 samples). The sensing platform was fabricated based on functionalized nylon nanofibrous membranes and a commercial glucose meter to enable easy deployment of the sensing technology. The fabrication of the immunoreaction vial using nylon nanofibrous membranes as a support matrix for the tethering of antibodies significantly improved the sensitivity of the detection platform in contrast to the use of conventional nylon casted membranes. The sensitivity of the nanofibrous membrane attached antibody was at least an order of magnitude higher (∼12 times) compared to the sensitivity of detection with regular casted membrane-based immunoreaction vial. The feasibility of the designed sensing platform was investigated using saliva as a non-invasive and self-administered sample for the diagnosis of SARS-CoV-2. With a detection limit of 9 ng mL−1 and no pretreatment processes required, the sensing platform demonstrated its suitability for the direct detection of SARS-CoV-2 spike protein in the spiked saliva samples. In addition, the developed platform depicted high agreement with RT-qPCR data in the analysis of the clinical samples with good stability over the storage time and reusability for three cycles with maintaining more than 95% of its original activity.