Tongue depressor (bio)sensors: A fast decentralized self-testing of salivary biomarkers for personalized medicine

Author(s)

de Lima, Lucas Felipe ; Ferreira, Andre Lopes ; do Nascimento, Guida Hellen Mota ; Cardoso, Luana Pereira ; de Jesus, Marcelo Bispo ; de Araujo, William Reis

• Document type: Journal article
• Source: CHEMICAL ENGINEERING JOURNAL; v. 494, p. 13-pg., 2024-06-18.

Abstract

The clinical tests usually make use of blood samples, requiring invasive sample collection protocols, which are not appropriate for decentralized, frequent, and point-of-care (POC) applications. Here, we report disposable (bio)sensors combining electrochemical and colorimetric technologies on an accessible and lightweight wooden tongue depressor platform. The array of (bio)sensors on this commonly used medical tool enables rapid, and safe saliva sampling and showed promise to be used for frequent self-testing of four clinically relevant biomarkers (glucose, uric acid, nitrite, and thiocyanate) in saliva. The electrochemical system was designed to detect uric acid and glucose by chronoamperometric measurements in clinically relevant concentrations ranging from 50 to 500 mu mol L- 1 and from 10 to 5000 mu mol L-1,-1 , respectively. Meanwhile, the colorimetric paper-based spot tests were optimized to detect nitrite and thiocyanate in concentrations ranging from 5 to 200 mu mol L- 1 and 0.5 to 2.1 mmol L-1,-1 , respectively, using digital image colorimetry. Our affordable tongue depressor (bio)sensors provide results within 5 min and achieve limits of detection in the mu mol L- 1 range. Importantly, the results provided by our tests when applied to human saliva samples presented excellent concordance with the traditional spectrophotometric method (at a 95 % confidence level), demonstrating the reliability and robustness of our method. In addition, the toxicity and biocompatibility studies of the tongue depressor (bio)sensors were evaluated using 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Calcein acetoxymethyl ester (Calcein AM), and Calcein Propidium Iodide Hoechst (Calcein PI) Analysis, confirming the safety use of the test. Therefore, our tongue depressor (bio)sensor facilitates frequent testing of several biomarkers and can contribute to personalized medicine. (AU)

• FAPESP's process: 22/09892-0 - Investigations of the therapeutic and cytotoxic effects of metallic nanoparticles under the influence of biomolecular coronas
• Grantee: Luana Pereira Cardoso
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 23/03483-4 - Fabrication of miniaturized and microfluidic wearable biosensors using 3D bioprinting technology
• Grantee: Guida Hellen Mota do Nascimento
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 23/05204-5 - Development of dsRNA delivery platforms for insect control in agriculture
• Grantee: André Lopes Ferreira
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 23/12589-0 - Fabrication of multiplex electrochemical (bio)sensors by CO2 laser engraving aiming the development of wearable devices.
• Grantee: Lucas Felipe de Lima
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 23/06143-0 - Molecular aspects of the nano-cell interactions: therapeutic activity, delivery of oligonucleotides and nanotoxicity
• Grantee: Marcelo Bispo de Jesus
• Support Opportunities: Regular Research Grants
• FAPESP's process: 23/00246-1 - Miniaturized large-scale devices for in-situ analysis: fabrication, characterization and applications
• Grantee: Mauro Bertotti
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/08782-1 - Miniaturized and integrated chemical sensors: new fabrication platforms for biological, clinical and environmental applications
• Grantee: Mauro Bertotti
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/03250-7 - Development of portable and cost-effective biosensors for clinical diagnosis of bacterial and viral infections
• Grantee: William Reis de Araujo
• Support Opportunities: Research Grants - Initial Project