An Aptamer-Based Point-of-Care Diagnostic Test Strip for Rapid Diagnosis of Surface Spike Proteins of Sars-Cov2 Virus

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has been identified as the causative agent for the COVID-19 pandemic. Herein, we report the development of a point-of-care diagnostic (POC) test strip for rapid and specific diagnosis of surface spike protein (S-protein) of SARS-CoV2 virus, as a target analyte for the virus diagnosis. The test detects changes in the physicochemical properties of gold nanoparticles with the utility of a DNA aptamer that is specifically selected for binding to the receptor-binding domain (RBD) of S-protein of SARS-CoV-2. Structural changes in aptamer enables the aggregation/disaggregation of gold nanoparticles in the absence/presence of the target analyte, respectively. Lateral flow assays were utilized to visualize results and stratify positive samples (containing viral S-protein) from negative samples (blank) with high specificity and sensitivity (1 to 10 nM) within about 2 minutes. The proposed sensing technology was successfully developed for rapid quantification of SARS-CoV2 S-protein; however, it can be further adapted to detect variants, viral DNA/RNA, and other targets, enabling the development of POC devices for multiplexing assays.