Saliva-based COVID-19 detection: A rapid antigen test of SARS-CoV-2 nucleocapsid protein using an electrical-double-layer gated field-effect transistor-based biosensing system

Immunoassay platform with surface-enhanced resonance Raman scattering for detecting trace levels of SARS-CoV-2 spike protein

“…The spike protein could also be detected in sensing chips containing metamaterials and using terahertz time-domain spectroscopy [ 23 ], and with magnetic microrobots immuno-sandwich assays [ 24 ]. For diagnosis of Covid-19 through detection of nucleocapsid protein, Chen et al [ 25 ] constructed an electrical double layer biosensor, while Qi et al [ 26 ] designed a fast-responding aptasensor based on a low-cost microelectrode array chip. RNA fragments have also been applied in detecting Covid-19 with a one-pot loop probe-mediated isothermal amplification method [ 27 ].…”

A Label-Free Electrochemical Impedimetric Immunosensor with Biotinylated-Antibody for SARS-CoV-2 Nucleoprotein Detection in Saliva

“…After collecting samples through a nasopharyngeal swab [11,12], the laboratory-based NAATs need trained persons to perform virus lysis and nucleic acid extraction, limiting the NAATs in developing a point-of-care (POC) device. Antigen detection based on an affinity reaction, such as the spike (S) protein (S-protein) [13][14][15][16][17][18], the S-protein receptor-binding domain (RBD) [19,20], and nucleocapsid protein (N-protein) [21][22][23][24][25][26], is popularly used for the diagnostics of early-stage COVID-19 disease. Compared to the NAAT-based assay, the operational procedures and testing time of viral antigen diagnostics are easy and rapid (within 60 min) [21][22][23][24][25][26].…”

“…LFIA strips for SARS-CoV-2 N-protein have excellent specificity (approximate 100%) but ordinary sensitivity (about 80%) [29], which is suitable for the rapid qualified detection of COVID-19 disease [30]. Biosensors integrating specific recognition molecules with sensitive transducers have attracted wide attention for developing sensitive POC devices [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Among different transducers, electrochemical detectors possess a promising potential to construct POC biosensing platforms due to good compatibility with portable electrical readers, ease of large-scale electrode production, and well-developed immobilization techniques of recognition molecules on various electrodes.…”

“…Nasopharyngeal or oropharyngeal swap sampling is a semi-invasive specimen collection that causes discomfort in testers. In contrast, salivary detection permits noninvasive sampling, which has great potential as an alternative method for rapid COVID-19 screenings [10,11,17,22,31,39].…”

Enhanced susceptibility of SARS-CoV-2 spike RBD protein assay targeted by cellular receptors ACE2 and CD147: Multivariate data analysis of multisine impedimetric response

“…Nowadays, the reverse transcription-polymerase chain reaction (RT-PCR)-based test for viral RNA detection is considered the standard gold method for the diagnosis of COVID-19 [14] . However, the price of a single test and the time it takes have forced the entire scientific community to research and develop new ways to quickly and cheaply detect SARS-Cov-2 [15] , [16] . Recently, impedimetric [17] , [18] , [19] , [20] and resistive [21] , [22] biosensors were considered as selective and rapid platforms for the determination of the SARS-CoV-2 spike S1 protein.…”