Rapid, multiplexed, and nucleic acid amplification-free detection of SARS-CoV-2 RNA using an electrochemical biosensor

Methylene Blue functionalized carbon nanodots combined with different shape gold nanostructures for sensitive and selective SARS-CoV-2 sensing

“… Target analyte Fundament Method L.O.D. Analysis Time Reference N-gene Electropolymerized polyaniline (PANI) nanowires DPV 3.5 fM 1.5 hours [39] N-gene Gold nanoparticles capped with antisense oligonucleotides Signal conditioning circuit 6.9 copies/μL 5 min [40] S and Orf1ab genes Four-way junction (4-WJ) hybridization SWV 5.0 ag/μL 1 hour [41] ORF1ab MoS 2 DPV 1.01 pM 2 hour [22] ORF1ab Catalytic hairpin assembly DPV 26 fM 3 hours [23] ORF1ab Gold nanomaterial and MB-CDs DPV 2.2 aM 1.5 hours Present work …”

“…Nanomaterials have also been used as electrode modifiers to improve sensitivity and selectivity in electrochemical DNA biosensors development [2] , [6] , [23] , [24] , [25] , [26] , [27] , [28] . Despite there are many strategies centered on the use of nanomaterials in biosensor´s design, most of them include many steps and complicated procedures, being still an area of great interest.…”

Biosensors as Nano-Analytical Tools for COVID-19 Detection

“…Some significant obstacles, such as low hybridization process efficiency and poor sensitivity on the surfaces of bulk electrodes, have been encountered by nucleic acid-based biosensors designed for analyzing clinical samples. Such problems are solved through the use of a gold nanoneedle structured electrode, as it increases the surface area of the electrode, which enhances the working capability of the biosensor [ 94 ]. To target the viral nucleocapsid phosphoprotein (N-gene), the biosensor uses gold nanoparticles (AuNPs), capped with highly selective antisense oligonucleotides (ssDNA).…”

Viral Respiratory Infections: New Tools for a Rapid Diagnosis

“…Among the latter, electrochemical biosensors possess advantages such as the possibility to do multiplex analysis, give fast results, and ease of use as POC tests. 121 Chaibun et al have devised an electrochemical biosensor, capable of detecting the N and S genes of SARS CoV-2, with a detection limit of 1 copy/μL in less than 2 hours, which evaluated on 106 clinical specimens showed 100% concordance with Real-Time Quantitative Reverse Transcription PCR. The assay involves first the multiplex isothermal rolling circle amplification (RCA), then the hybridization of the produced amplicons with probes, silica nanoparticles, coated with redox dyes and finally the production and detection of a current signal (which completely correlates with the quantification cycle [Cq] values).…”