Label-free impedimetric immunosensor for point-of-care detection of COVID-19 antibodies

Lian C T Shoute; Gaser N Abdelrasoul; Yuhao Ma; Pedro A Duarte; Cole Edwards; Ran Zhuo; Jie Zeng; Yiwei Feng; Carmen L Charlton; Jamil N Kanji; Shawn Babiuk; Jie Chen

doi:10.1038/s41378-022-00460-5

Label-free impedimetric immunosensor for point-of-care detection of COVID-19 antibodies

Microsyst Nanoeng. 2023 Jan 1:9:3. doi: 10.1038/s41378-022-00460-5. eCollection 2023.

Authors

Lian C T Shoute¹, Gaser N Abdelrasoul¹, Yuhao Ma¹, Pedro A Duarte¹, Cole Edwards², Ran Zhuo², Jie Zeng¹, Yiwei Feng¹, Carmen L Charlton^{2

3

4}, Jamil N Kanji^{2

3

5

6}, Shawn Babiuk^{7

8}, Jie Chen^{1

9}

Affiliations

¹ Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 Canada.
² Public Health Laboratory, Alberta Precision Laboratories, Edmonton, AB Canada.
³ Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2B7 Canada.
⁴ Li Ka Shing Institute for Virology, University of Alberta, Edmonton, AB Canada.
⁵ Division of Infectious Diseases, Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB Canada.
⁶ Department of Pathology & Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB Canada.
⁷ National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB Canada.
⁸ Department of Immunology, University of Manitoba, Winnipeg, MB Canada.
⁹ Department of Biomedical Engineering, University of Alberta, Edmonton, AB T6G 2R3 Canada.

Abstract

The COVID-19 pandemic has posed enormous challenges for existing diagnostic tools to detect and monitor pathogens. Therefore, there is a need to develop point-of-care (POC) devices to perform fast, accurate, and accessible diagnostic methods to detect infections and monitor immune responses. Devices most amenable to miniaturization and suitable for POC applications are biosensors based on electrochemical detection. We have developed an impedimetric immunosensor based on an interdigitated microelectrode array (IMA) to detect and monitor SARS-CoV-2 antibodies in human serum. Conjugation chemistry was applied to functionalize and covalently immobilize the spike protein (S-protein) of SARS-CoV-2 on the surface of the IMA to serve as the recognition layer and specifically bind anti-spike antibodies. Antibodies bound to the S-proteins in the recognition layer result in an increase in capacitance and a consequent change in the impedance of the system. The impedimetric immunosensor is label-free and uses non-Faradaic impedance with low nonperturbing AC voltage for detection. The sensitivity of a capacitive immunosensor can be enhanced by simply tuning the ionic strength of the sample solution. The device exhibits an LOD of 0.4 BAU/ml, as determined from the standard curve using WHO IS for anti-SARS-CoV-2 immunoglobulins; this LOD is similar to the corresponding LODs reported for all validated and established commercial assays, which range from 0.41 to 4.81 BAU/ml. The proof-of-concept biosensor has been demonstrated to detect anti-spike antibodies in sera from patients infected with COVID-19 within 1 h. Photolithographically microfabricated interdigitated microelectrode array sensor chips & label-free impedimetric detection of COVID-19 antibody.

Keywords: Biosensors; NEMS.