RT-PCR is a real-time test which quantitatively detects the nucleic acid viral RNA of the viruses present in upper and lower respiratory specimens. Although it is considered the gold standard for diagnosis, PCR techniques (RT-PCR or RT-qPCR) have certain limitations. They suffer from a high rate of false negative results, particularly during the first week of infection before it turns positive [8; 9; 10]. During this period, patients can be infectious. Moreover, sample extraction and test preparation need a long turnaround time, rendering the sample processing time lengthy. The method takes 3-6 h from sample collection to result generation, and due to the huge number of requested tests, the time required to obtain the results can be up to 2-3 days [11]. Moreover, RT-qPCR-based testing requires trained personnel, sophisticated laboratory infrastructure, biosafety cabinets, and thermocyclers, which are not available in most healthcare settings, especially in underdeveloped and developing countries. The sensitivity and specificity of RT-PCR- or RT-qPCR-based diagnostics are tightly dependent on several factors, including sample quality and type, the timing of sample collection, the type of PCR assay used, the viral load, and the presence of inhibitors or mutations in the viral genome [12; 13; 14; 15]. This explains the relatively high rate of false negative and/or false positive results obtained, and consequently the need for multiple confirmatory testing, especially in mild cases where samples can test negative due to a low viral load [16; 17; 18; 19]. Importantly, RT-qPCR diagnostic kits are expensive and not always available (i.e., during the COVID-19 pandemic many countries suffered from a shortage). In addition, the emergence of virus variants has created difficulties in accurately diagnosing patients. The mutations in these strains have led to higher rates of false negative results and greater variation in the clinical manifestations of the disease [20]. Thus, it is imperative to find alternative approaches to detect SARS-CoV-2 and MERS-CoV viruses in a reliable, efficient, and cost-effective way without jeopardizing specificity and sensitivity. As new variants of the virus continue to emerge, the need for accurate and adaptable diagnostic methods is becoming more urgent. Given the continuous need for fast, sensitive, and cost-effective viral detection techniques, the advantages of using nano-based sensors are particularly promising. Since the emergence of SARS-CoV-2, numerous researchers and scientific experts have been exploring the potential of nanoparticle (NP)-based approaches for the efficient detection of the virus [21; 22; 23; 24]. In fact, NP-based methodologies have recently been found to be very effective in rapid detection, sensing, improvements, prevention (i.e., masks and personal protective equipment), vaccine development, and accessible automated viral testing [25]. In general, the use of nanomaterials has been reported to decrease detection time while increasing sensitivity, making it possible to design improved detection approaches for coronaviruses [23; 26]. The unique NP physicochemical properties, such as the magnetic properties of magnetic nanoparticles (MNPs), plasmonic properties of gold nanoparticles (AuNPs), electrochemical properties of carbon-based nanoparticles, and fluorescence properties of quantum dots, can be tailored according to their specific application requirements, making them a desirable platform for rapid, specific, and low-cost detection [21; 22]. Furthermore, surface functionalization with specific ligands, such as antibodies, peptides, proteins, etc., can improve the detection limit and specificity. Spike and nucleocapsid proteins, among others, are the most promising targets for antigen-based diagnostic tests [27; 28]. In particular, the spike S protein is the antigen that has been studied the most.