Development of Rapid Aptamer-Based Screening Assay for the Detection of Covid-19 Variants.

The development of a colorimetric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection assay with the WHO published ASSURED criteria is reported, in which the biosensor should have the following characteristics of (i) being affordable for low-income communities, (ii) sensitive, (iii) specific, (iv) user-friendly to be used by non-skilled personnel, (v) rapid and robust, (vi) equipment-free, and (vii) delivered to the end-users as a simple and easy to use point-of-care tool. Early viral infection detection prevents virus spread and controls the epidemic. We herein report the development of a colorimetric assay in which SARS-COV-2 variants can be detected by colorimetric observation of color on the sensing cotton swab surface. Using the developed biosensor assay, it is possible to discriminate between the various SARS-CoV-2 variants with a LOD of 100 ng/mL within 4 min including sample preconcentration and incubation step. The results illustrated the development of a SARS-CoV-2 colorimetric biosensor that can be mass produced, with low-reagent cost, and can be read-out visually in the field by nonskilled personnel.