Identification and ultrasensitive quantification of H. pylori infections on gastric and stool human samples with a photonic label-free nanobiosensor

Abstract

Helicobacter pylori is a widespread bacterium that infects the stomach, causing gastric disorders associated with high morbidity and mortality worldwide. Current methods for identifying and quantifying this pathogen rely on invasive and non-invasive tests. Although combining these methods allows accurate diagnosis, they have multiple drawbacks, and there is no single reliable gold standard test. New, more sensitive strategies involving molecular techniques, such as digital PCR, have been developed but require complex and expensive instruments. Herein, we implement and validat a nanophotonic bimodal waveguide (BiMW) biosensor for the sensitive and accurate detection of H. pylori in gastric biopsies and stool. This biosensor offers real-time, label-free detection, high sensitivity, and the capability to be integrated into compact devices. By employing monoclonal antibodies targeting specific membrane proteins found in H. pylori, the biosensor enables unique recognition of the bacterium, demonstrating its potential as an alternative diagnostic tool. The BiMW biosensor provides highly accurate H. pylori quantification in under 20 min, with limits of detection (LOD) of 89 ± 35 CFU/mL for antrum gastric biopsies and 82 ± 9 CFU/mL for stool samples. Clinical validation with 40 samples (20 gastric biopsies and 20 stool samples) showed sensitivity and specificity of 90 % for gastric biopsies and 95 % for stool samples, offering diagnostic reliability equivalent to semiquantitative ELISA tests and enabling more efficient and timely detection of H. pylori infections. This test can significantly improve the speed of diagnosis and contribute to the development of more effective strategies for H. pylori eradication.

Keywords: Bimodal waveguide; Biosensor; Diagnosis; Gastric cancer; Helicobacter pylori; Nanophotonics.