Capacitive Aptasensor Coupled with Microfluidic Enrichment for Real-Time Detection of Trace SARS-CoV-2 Nucleocapsid Protein

Abstract

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has lasted for almost 2 years. Stemming its spread has posed severe challenges for clinical virus detection. A long turnaround time, complicated operation, and low accuracy have become bottlenecks in developing detection techniques. Adopting a direct antigen detection strategy, we developed a fast-responding and quantitative capacitive aptasensor for ultratrace nucleocapsid protein detection based on a low-cost microelectrode array (MEA) chip. Employing the solid–liquid interface capacitance with a sensitivity of picofarad level, the tiny change on the MEA surface can be definitively detected. As a result, the limit of detection reaches an ultralow level of femtogram per milliliter in different matrices. Integrated with efficient microfluidic enrichment, the response time of this sensor from the sample to the result is shortened to 15 s, completely meeting the real-time detection demand. Moreover, the wide linear range of the sensor is from 10 –5 to 10 –2 ng/mL, and a high selectivity of 6369:1 is achieved. After application and evaluation in different environmental and body fluid matrices, this sensor and the detection method have proved to be a label-free, real-time, easy-to-operate, and specific strategy for SARS-CoV-2 screening and diagnosis.

Microfluidics Technology in SARS-CoV-2 Diagnosis and Beyond: A Systematic Review

“…A microelectrode array (MEA) chip that contains a specific aptamer can detect a small amount of SARS-CoV-2 N protein from the sample providing a competitive solution for real-time and low-cost SARS-CoV-2 screening and diagnosis. As an indicator, the aptasensor uses solid−liquid interface capacitance as an ultrasensitive indicator [ 42 ]. Another electrochemically-based biosensor is the MXene-graphene field-effect transistor (FET) which uses two-dimensional (2D) virus-sensing transduction material (VSTM) such as 2D transition metal carbides (MXenes) and graphene.…”

“…The aptasensor has a very low limit of detection (LOD); indifferent matrices femtogram per milliliter level, the MXene graphene FET sensor can detect the antigen in a concentration ranging from 1 fg/mL to 10 pg/mL. The aptasensor has a rapid response time of 15 s and a 10−5 to 10−2 ng/mL wide linear range, although the MXene graphene FET sensor requires ∼50 min to receive viruses in solution which is much higher [ 42 , 43 ].…”

Molecular dynamics simulation approach for discovering potential inhibitors against SARS-CoV-2: A structural review

“…SARS-CoV-2, which causes COVID-19, is much more contagious than SARS-CoV and MERS-CoV, which spreads from person to person and inflicts mortal disease [1] . Fever, nausea, dry cough, diarrhea, and shortness of breath are some of the signs of novel Coronavirus [ [2] , [3] , [4] ] that may escalate to acute respiratory diseases. The genome of SARS-CoV-2 encrypts structural molecules including S (spike glycoprotein), E (envelope), M (membrane), and N (nucleocapsid), as well as non-structural components as with M pro , papain-like protease (PLP), and RNA dependent RNA polymerase (RdRp).…”

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 ].…”