Multichannel nanosensor for rapid virus discrimination using fluorescence sensing pattern array of quantum dot-gold nanoparticle nano-assemblies

Diagnostic methods that use conventional genomic, proteomic, and receptor-based signatures to detect viruses are known. However, they require specialized equipment and personnel for operation, are time consuming and are restricted to the “lock and key” mode of operation. This work reports on the construction of a high-throughput multichannel pattern array sensor platform that can discriminate various viruses rapidly in buffer and in complex matrix and which also can quantitatively discriminate the viruses. The sensor consists of fluorescent semiconductor quantum dots (QDs) capped with four different thiol ligands, namely, 3-mercaptopropionic acid (MPA), L-cysteine (L-cyst), N-acetyl-L-cysteine (NAC) and L-glutathione (GSH) and gold nanoparticles (AuNPs) capped with cationic cetyltrimethylammonium bromide (CTAB). The electrostatic interaction between the negatively charged thiol-capped QDs and the cationic CTAB-AuNP resulted in either a quenched or enhanced fluorescence process. The differing fluorescence process was attributed to the nature of the QDs capping ligand interaction with cationic AuNPs. In the presence of the virus, immobilized AuNPs were displaced from the QDs surface and the QDs fluorescence was restored by localized surface plasmon resonance induced fluorescence intensity. Principal component analysis (PCA), efficiently discriminated the QDs-AuNP array fluorescence intensity data for SARS-CoV 2 spike protein, influenza virus, dengue virus and BK polyomavirus in buffer and in spiked human serum without any overlap. In addition, linear discriminate analysis (LDA) quantitatively discriminated the QDs-AuNP array fluorescence intensity data for different concentrations of SARS-CoV 2 spike protein. The developed QDs-AuNP patterned array sensor is the first of its kind reported for virus discrimination.