Application of concanavalin A as a new diagnostic strategy for SARS-COV-2 spike protein

Abstract

The coronavirus disease 2019 (COVID-19) pandemic was the first modern global public health crisis recognized for overwhelming the health public system. In the viral envelope, there are glycoproteins that can be identified, making them useful in diagnosing infections such as the one caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this work, we developed a sensor platform applicable to the identification of carbohydrates present in the spike protein of SARS-CoV-2. The nanostructured platform was composed of a thin film of poly (thiophene-3-acetic acid) (PTAA) and nano gold urchins (AuNUs), enhancing the electrical signal at the interface of the gold electrode. Coupled to this nanostructured layer, the lectin Concanavalin A (ConA) was immobilized, which has binding affinity to mannose and N-acetylglucosamine residues. In this context, ConA was used as a biorecognition element against Spike protein carbohydrates. Gradual assembly of the sensor platform and recombinant viral target recognition were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM). The proposed biosensor showed high sensitivity, with a limit of detection (LOD) of Spike isolated 0.20 ng/µL and Spike serum 0.14 ng/µL, along with high selectivity against interfering molecules. Our results stand out as an innovative alternative for detecting viral glycoproteins, with promising applications in detecting SARS-CoV-2 in clinical samples.