All-solid-state SARS-CoV-2 protein biosensor employing colloidal quantum dots-modified electrode

Abstract

Rapid and reliable detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody can provide immunological evidence in addition to nucleic acid test for the early diagnosis and on-site screening of coronavirus disease 2019 (COVID-19). All-solid-state biosensor capable of rapid, quantitative SARS-CoV-2 antibody testing is still lacking. Herein, we propose an electronic labelling strategy of protein molecules and demonstrate SARS-CoV-2 protein biosensor employing colloidal quantum dots (CQDs)-modified electrode. The feature current peak corresponding to the specific binding reaction of SARS-CoV-2 antigen and antibody proteins was observed for the first time. The unique charging and discharging effect depending on the alternating voltage applied was ascribed to the quantum confinement, Coulomb blockade and quantum tunneling effects of quantum dots. CQDs-modified electrode could recognize the specific binding reaction between antigen and antibody and then transduce it into significant electrical current. In the case of serum specimens from COVID-19 patient samples, the all-solid-state protein biosensor provides quantitative analysis of SARS-CoV-2 antibody with correlation coefficient of 93.8% compared to enzyme-linked immunosorbent assay (ELISA) results. It discriminates patient and normal samples with accuracy of about 90%. The results could be read within 1 min by handheld testing system prototype. The sensitive and specific protein biosensor combines the advantages of rapidity, accuracy, and convenience, facilitating the implement of low-cost, high-throughput immunological diagnostic technique for clinical lab, point-of-care testing (POCT) as well as home-use test.

Novel electrochemical PMI marker biosensor based on quantum dot dissolution using a double-label strategy

“…All analytical parameters are summarized in Table S2 . The analytical parameters obtained in this study and those of previously reported QD-based biosensors are compared in Table 1 32 – 38 , demonstrating the high sensitivity of the GAPDH sensor developed in this work.

Figure 4 Calibration plot using the stripping-current response.

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Electrochemical Biosensor Employing Bi2S3 Nanocrystals-Modified Electrode for Bladder Cancer Biomarker Detection

“…Here, R 1 , C, R ct , and Q represent the solution resistance, film capacitance, the charge transfer resistance, and the capacitance of the electrical double layer located at the electrode-electrolyte interface. With the increase of CK18 antigen concentration, the antibody and antigen specific binding reactions located at the electrode-electrolyte interface were more active, causing the change of modification layer on the WE, which may lead to the slight increase initially and subsequent decrease of R 1 (Figure 6c) [39]. When the CK18 antigen was added to the reaction system, the value of C decreased, but remained relatively stable with the increase of CK18 antigen concentration.…”

Nanomaterials for virus sensing and tracking

“…327 The quantum tunneling and confinement behaviour in addition to the coulomb blockade present in quantum dots results in extraordinary charging response to alternating potential which can be exploited to develop SARS-CoV-2 sensors which can differentiate between normal and patient samples with nearly 90% accuracy. 328…”