Electrochemical Detection of SARS‐CoV‐2 in Saliva Using ZnO Nanorods Functionalized with Gold‐Conjugated Antireceptor‐Binding Domain Antibodies
The COVID‐19 pandemic highlights the urgent need for rapid, accessible, and cost‐effective diagnostic technologies. Traditional diagnostic methods, although effective, often require high‐cost equipment and lengthy processing times. Herein, the development of an electrochemical immunosensor based on fluorine‐doped tin oxide (FTO) electrodes modified with zinc oxide nanorods (ZnONRs) for detecting the receptor‐binding domain (RBD) of SARS‐CoV‐2 in saliva is presented. ZnONRs offer a favorable platform due to their large surface area, low production cost, and efficient electron transport properties. To improve selectivity and sensitivity, ZnONRs are functionalized with monoclonal antibodies (mAbs) conjugated to gold nanoparticles (AuNPs). Four murine anti‐RBD mAbs (2B9F9, 3E5G8, 4B1D3, and 4H4A2) are evaluated by ELISA and electrochemical methods. While all mAbs demonstrate recognition of the RBD in ELISA, only the 4B1D3 mAb produces a measurable electrochemical signal, achieving a detection limit of 1.7 μg mL −1 and exhibiting recognition of both the original Wuhan‐Hu‐1 strain and the Omicron variant. The immunosensor demonstrates excellent performance in tests with real human saliva samples, reinforcing its potential as a noninvasive, rapid, and scalable platform for point‐of‐care viral diagnostics.
Authors
- Wendel Andrade Alves (ORCID: https://orcid.org/0000-0002-8394-2751)
- Jorge Kalil (ORCID: https://orcid.org/0000-0001-8415-4274)
- Francesca Cavalieri (ORCID: https://orcid.org/0000-0001-5391-5069)
- Lídia M. Andrade (ORCID: https://orcid.org/0000-0003-2594-4617)
- Mariano Venanzi (ORCID: https://orcid.org/0000-0001-9364-7441)
- Vivian L. de Oliveira (ORCID: https://orcid.org/0000-0003-2523-0374)
- Mariângela de Oliveira Silva (ORCID: https://orcid.org/0000-0002-0975-7187)
- Tamires Lopes Silva (ORCID: https://orcid.org/0000-0001-5118-0556)
- Ana Cristina Honorato de Castro (ORCID: https://orcid.org/0000-0003-0930-2112)
- Silvia Beatriz Boscardin (ORCID: https://orcid.org/0000-0002-7845-7110)
- Sydney Ferreira Santos (ORCID: https://orcid.org/0000-0003-1276-4086)
- Isabela Pazotti Daher (ORCID: https://orcid.org/0000-0002-5699-0619)
- Fabiola L. Castro (ORCID: https://orcid.org/0009-0001-5914-3087)
- Catarina Harumi Oda Ibrahim (ORCID: https://orcid.org/0000-0002-6585-9348)
- Priscila S. Ferreira (ORCID: https://orcid.org/0009-0005-7789-6380)
- M. R. Silva
Institutions
- Universidade Federal de Minas Gerais (BR)
- University of Rome Tor Vergata (IT)
- Universidade de São Paulo (BR)
- Institute of Biomedical Science (GB)
- Universidade Federal do ABC (BR)
Publication Details
- Journal
- ChemNanoMat
- Published
- 2025-10-28
- DOI
- https://doi.org/10.1002/cnma.202500411
- Primary Topic
- SARS-CoV-2 detection and testing
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Universidade Federal do ABC
- Fundação de Amparo à Pesquisa do Estado de São Paulo
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Fundação de Amparo à Pesquisa do Estado de Minas Gerais
- Università degli Studi di Roma Tor Vergata
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica