Study on the establishment of a paper lateral flow immunoassay for human Helicobacter pylori antigen detection

Abstract

Helicobacter pylori (Hp) infection is a major culprit leading to chronic gastritis, gastric ulcers, and even gastric cancer. Early detection helps facilitate timely clinical treatment. To improve the sensitivity, specificity, and stability of traditional colloidal gold lateral flow immunoassay (LFIA) for Hp antigen detection, it is necessary to enhance the colloidal gold labeling process and optimize the chromatographic system. In this study, colloidal gold particles of different sizes were prepared using the citrate reduction method, and 20 nm colloidal gold particles were ultimately selected as the labeling carrier to maintain high antibody activity while ensuring coupling efficiency. The optimized colloidal gold labeling process was as follows: coating particles were dispersed with K₂CO₃ solution (2% mass fraction, pH 12.5), followed by adding antibodies and shaking to form coating complexes. The complexes were suspended and stored in a resuspension buffer containing 0.05 mol/L PB (pH 7.4), 5% sucrose, 1% BSA, and 0.1% Tween-20.