Noninvasive electrochemical biosensor for rapid detection of Helicobacter pylori in patient saliva

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da Silva, Stella Schuster ; Valerio, Tatiana Lima ; Hryniewicz, Bruna M. ; Jaradat, Hussamaldeen ; Araujo, Mel De Souza Wendhausen ; Royer, Carla Adriane ; Ortiz, Beatriz Borba ; Deller, Andrei Elias ; Kashiwagui, Leandro Yoshimi ; Guimaraes, Paulo de Souza Fonseca ; Oliveira, Jaqueline de Carvalho ; Gradia, Daniela Fiori ; Kanoun, Olfa ; de Oliveira, Carolina Camargo ; Vidotti, Marcio

• Document type: Journal article
• Source: SENSORS AND ACTUATORS B-CHEMICAL; v. 442, p. 10-pg., 2025-11-01.

Abstract

The carcinogenic bacterium Helicobacter pylori infect over half the global population, with a higher prevalence in low-income countries. It is linked to diseases such as chronic gastritis, peptic ulcers, and gastric cancer, a leading cause of cancer-related deaths worldwide. The gold standard diagnostic method involves histopathological evaluation of gastric biopsy tissue via upper gastrointestinal endoscopy-an invasive, complex, and timeintensive procedure requiring specialized professionals. This study presents a noninvasive alternative: an impedimetric electrochemical biosensor for H. pylori antigen detection in saliva. The biosensor was developed using a screen-printed carbon electrode modified with polypyrrole nanotubes and carboxylated multi-walled carbon nanotubes. Monoclonal antibodies targeting CagA, a cytotoxic effector protein of H. pylori, were immobilized on carbon nanotubes using EDC/NHS chemistry. The platform was characterized via scanning electron microscopy and electrochemical techniques. Electrochemical impedance spectroscopy (EIS) was employed for analyte detection, with an analytical curve constructed in phosphate-buffered saline (PBS) spiked with CagA protein. The biosensor demonstrated a linear detection range of 0.5 pg mL 1 to 3.3 ng mL 1 and a detection limit of 109.9 fg mL 1 . Validation with patient saliva samples, confirmed by histopathology and rapid urease testing, yielded 97 % accuracy, 80 % sensitivity, and 100 % specificity. Results were obtained within 15 min. This EIS-based biosensor offers a sensitive, innovative, and noninvasive platform for early H. pylori diagnosis, which is essential for preventing severe diseases such as gastric cancer. (AU)

• FAPESP's process: 14/50867-3 - INCT 2014: National Institute of Science and Technology in Bioanalysis
• Grantee: Marco Aurelio Zezzi Arruda
• Support Opportunities: Research Projects - Thematic Grants