Development of a miniaturized chemiluminescence lateral flow immunoassay platform with ultra-high sensitivity and ultra-low background for cardiac troponin I.

BACKGROUND

Lateral flow immunoassays (LFA) are widely used for disease diagnostics due to their simplicity and portability. However, they often suffer from limited sensitivity and accuracy, making them unsuitable for quantitative detection. Additionally, the adsorption and non-specific interactions between label particles and the nitrocellulose membrane may lead to increased background noise, which compromises the repeatability of the device. Therefore, there is an urgent need to develop a highly sensitive, accurate, and high signal-to-noise ratio LFA device that is free from background noise interference.

RESULTS

We developed a miniaturized LFA platform that achieves dual-enhanced colorimetric and chemiluminescence signals with ultra-low background noise for detecting cardiac troponin I. The enhancement is achieved through the sequential addition of horseradish peroxidase-streptavidin (HRP-SA) and multiple layers of biotin-antibody (Bio-Ab) conjugated to gold nanoparticles. This conjugation alters the surface charge state of the particles, reducing nonspecific adsorption to the nitrocellulose membrane and significantly lowering background noise. Additionally, the multilayered Bio-Ab coatings and the robust interaction between streptavidin and biotin markedly increase antibody loading, further enhancing the device's sensitivity. A compact smartphone-based imaging setup combined with a high-resolution lens was used for signal readout. The assay strip demonstrated a colorimetric detection range of 100 pg/mL to 10 ng/mL and a chemiluminescent detection range of 10 pg/mL to 10 ng/mL.

SIGNIFICANCE

This work establishes a new foundational methodology for chemiluminescence LFA, offering a simpler and more accessible approach that does not require complex equipment, making it ideal for the rapid and on-site diagnosis of acute myocardial infarction. We firmly believe that this method holds great potential for widespread applications in sensitive, and rapid disease diagnosis.