Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human saliva
Periodontal disease (PD) is a chronic inflammatory condition triggered by bacterial biofilms and progresses through two main stages: gingivitis and periodontitis. The existing diagnostic methods remain time-consuming and require clinical expertise. Salivary nitrite, a stable end-product of nitric ox...
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Elsevier
2025-08-01
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| Series: | Sensing and Bio-Sensing Research |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214180425001266 |
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| author | Sara Rodrigues Gaspar Luís Proença Ricardo Alves Maria Gabriela Almeida |
| author_facet | Sara Rodrigues Gaspar Luís Proença Ricardo Alves Maria Gabriela Almeida |
| author_sort | Sara Rodrigues Gaspar |
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| description | Periodontal disease (PD) is a chronic inflammatory condition triggered by bacterial biofilms and progresses through two main stages: gingivitis and periodontitis. The existing diagnostic methods remain time-consuming and require clinical expertise. Salivary nitrite, a stable end-product of nitric oxide produced during inflammation, has emerged as a promising biomarker for PD. However, its reliable quantification in saliva typically relies on laboratory-based assays that are unsuited to clinical workflows.This study aimed to test and validate a new nitrite point-of-care test (POCT) for oral medicine. Building on previous research, we developed a biosensing platform based on screen-printed carbon electrodes modified with a selective enzyme, the cytochrome c nitrite reductase. To adapt bioelectrodes for salivary analysis, they were further modified with a poly(vinyl) alcohol coating and a biochemical oxygen scavenger system (ascorbate oxidase and ascorbate). The nitrite biosensor achieved a suitable linear range of 5–300 μM, with a sensitivity of 0.015 μM−1, validated against the gold-standard Griess method. Unlike the Griess reaction, the biosensor was unaffected by sample turbidity, rendering centrifugation unnecessary. Additionally, we observed that sample freezing altered nitrite concentrations, increasing levels in non-centrifuged samples, while decreasing them in previously clarified samples. These findings highlight the need for real-time analysis and call into question the reliability of previously published data that overlooked these variables. Therefore, our results demonstrate the potential of the nitrite biosensor as a novel salivary POCT and emphasize the critical need for standardized sample-handling protocols. |
| format | Article |
| id | doaj-art-70e2ee252b4441ef9f0827b06867ec66 |
| institution | Kabale University |
| issn | 2214-1804 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Elsevier |
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| series | Sensing and Bio-Sensing Research |
| spelling | doaj-art-70e2ee252b4441ef9f0827b06867ec662025-08-20T03:59:37ZengElsevierSensing and Bio-Sensing Research2214-18042025-08-014910086010.1016/j.sbsr.2025.100860Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human salivaSara Rodrigues Gaspar0Luís Proença1Ricardo Alves2Maria Gabriela Almeida3Departamento de Química, Associate Laboratory i4HB – Institute for Health and Bioeconomy, UCIBIO – Applied Molecular Biosciences Unit, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Monte de Caparica, PortugalEgas Moniz Center for Interdisciplinary Research (CiiEM), Egas Moniz School of Health & Science, 2829-511 Caparica, PortugalEgas Moniz Center for Interdisciplinary Research (CiiEM), Egas Moniz School of Health & Science, 2829-511 Caparica, PortugalDepartamento de Química, Associate Laboratory i4HB – Institute for Health and Bioeconomy, UCIBIO – Applied Molecular Biosciences Unit, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Monte de Caparica, Portugal; Egas Moniz Center for Interdisciplinary Research (CiiEM), Egas Moniz School of Health & Science, 2829-511 Caparica, Portugal; Corresponding author at: Departamento de Química, Associate Laboratory i4HB – Institute for Health and Bioeconomy, UCIBIO – Applied Molecular Biosciences Unit, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Monte de Caparica, Portugal.Periodontal disease (PD) is a chronic inflammatory condition triggered by bacterial biofilms and progresses through two main stages: gingivitis and periodontitis. The existing diagnostic methods remain time-consuming and require clinical expertise. Salivary nitrite, a stable end-product of nitric oxide produced during inflammation, has emerged as a promising biomarker for PD. However, its reliable quantification in saliva typically relies on laboratory-based assays that are unsuited to clinical workflows.This study aimed to test and validate a new nitrite point-of-care test (POCT) for oral medicine. Building on previous research, we developed a biosensing platform based on screen-printed carbon electrodes modified with a selective enzyme, the cytochrome c nitrite reductase. To adapt bioelectrodes for salivary analysis, they were further modified with a poly(vinyl) alcohol coating and a biochemical oxygen scavenger system (ascorbate oxidase and ascorbate). The nitrite biosensor achieved a suitable linear range of 5–300 μM, with a sensitivity of 0.015 μM−1, validated against the gold-standard Griess method. Unlike the Griess reaction, the biosensor was unaffected by sample turbidity, rendering centrifugation unnecessary. Additionally, we observed that sample freezing altered nitrite concentrations, increasing levels in non-centrifuged samples, while decreasing them in previously clarified samples. These findings highlight the need for real-time analysis and call into question the reliability of previously published data that overlooked these variables. Therefore, our results demonstrate the potential of the nitrite biosensor as a novel salivary POCT and emphasize the critical need for standardized sample-handling protocols.http://www.sciencedirect.com/science/article/pii/S2214180425001266Periodontal diseaseSalivaNitriteBiosensorsPoint-of-care test |
| spellingShingle | Sara Rodrigues Gaspar Luís Proença Ricardo Alves Maria Gabriela Almeida Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human saliva Sensing and Bio-Sensing Research Periodontal disease Saliva Nitrite Biosensors Point-of-care test |
| title | Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human saliva |
| title_full | Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human saliva |
| title_fullStr | Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human saliva |
| title_full_unstemmed | Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human saliva |
| title_short | Point-of-care testing of nitrite in oral medicine - Application and validation of an enzymatic biosensor in human saliva |
| title_sort | point of care testing of nitrite in oral medicine application and validation of an enzymatic biosensor in human saliva |
| topic | Periodontal disease Saliva Nitrite Biosensors Point-of-care test |
| url | http://www.sciencedirect.com/science/article/pii/S2214180425001266 |
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