N protein‐based ultrasensitive SARS‐CoV‐2 antibody detection in seconds via 3D nanoprinted, microarchitected array electrodes

Abstract

Rapid detection of antibodies to SARS-CoV-2 is critical for COVID-19 diagnostics, epidemiological research, and studies related to vaccine evaluation. It is known that the nucleocapsid (N) is the most abundant protein of SARS-CoV-2 and can serve as an excellent biomarker due to its strong immunogenicity. This paper reports a rapid and ultrasensitive 3D biosensor for quantification of COVID-19 antibodies in seconds via electrochemical transduction. This sensor consists of an array of threedimensional micro-length-scale electrode architecture that is fabricated by aerosol jet 3D printing, which is an additive manufacturing technique. The micropillar array is coated with N proteins via an intermediate layer of nano-graphene and is integrated into a microfluidic channel to complete an electrochemical cell that uses antibodyantigen interaction to detect the antibodies to the N protein. Due to the structural innovation in the electrode geometry, the sensing is achieved in seconds, and the sensor shows an excellent limit of detection of 13 fm and an optimal detection range of 100 fm to 1 nM. Furthermore, the sensor can be regenerated at least 10 times, which reduces the cost per test. This work provides a powerful platform for rapid screening of antibodies to SARS-CoV-2 after infection or vaccination.

Progress in Electrochemical Biosensing of SARS-CoV-2 Virus for COVID-19 Management

“…Concurrently, the immunosensor exhibits a wide linear range for the detection of anti-IgG with the LOD of 1 ng/mL. In another report, Ali et al prepared an ultrasensitive and label-free 3D biosensor based on a micropillar array of Au nanoparticles (AuNPs) coated with rGO sheets (Figure 3b) [55]. Subsequently, the SARS-CoV-2 NP was immobilized onto the AuNPs/rGO-modified micropillar array via (3-dimethylaminopropyl)-Nethylcarbodiimide (EDC)-N-hydroxysulfosuccinimide (NHS) coupling chemistry.…”

Ultrarapid and ultrasensitive detection of SARS‐CoV‐2 antibodies in COVID‐19 patients via a 3D‐printed nanomaterial‐based biosensing platform

“…For immobilization, the concentrations of all the antigens were set to 5 μg/ml. Two rabbit IgG antibodies to S1 and RBD, and a mouse monoclonal antibody (IgG) to N protein were purchased from Sino Biological Inc. 50,53 For titration measurements, the antibody solutions of S1, RBD, and N were prepared in a phosphate-buffered solution (PBS) of pH 7.4 (50 mM) containing an equimolar concentration of 5 mM of ferro and ferricyanide. We used the same PBS for serial dilution and spiking antibodies.…”

“…In addition to the incredibly short time, this label‐free platform shows an ultra‐low limit‐of‐detection (LoD) down to the femtomolar level of antibody concentrations 40 . This sensor 40,50 demonstrated sensing capability for multiple SARS‐CoV‐2 antibodies to S and N proteins, which is a feature not found in other sensors. The method, however, was successfully tested only on rabbit‐derived antibodies and its validation on human samples remained to be done.…”

Magnetic/fluorescent dual-modal lateral flow immunoassay based on multifunctional nanobeads for rapid and accurate SARS-CoV-2 nucleocapsid protein detection

“…NP is a structure protein of SARS-CoV-2 virus [ 13 ]. Compared with other structure proteins, NP has high immunogenicity and is more abundantly expressed in vivo during infection [ 14 , 15 ]. Hence, NP is a suitable marker for diagnosing SARS-CoV-2 in early infection.…”