Minimizing Cross-Reactivity for the Chemiluminescent Lateral Flow Immunoassay of Cardiac Troponin I Based on PEGylation of Gold Nanoparticles

Lateral flow immunoassays (LFIAs) have been employed extensively for the rapid, accurate, and portable detection of protein biomarkers in healthcare. However, the cross-reactivity, especially in the multiplexed detection, leads to false-positive errors that would further limit their practical applications. In this work, we report a highly sensitive and accurate chemiluminescent LFIA based on the synthesis of the Au nanoparticle-antibody-horseradish peroxidase-polyethylene glycol conjugate for detecting cardiac troponin I (cTnI), a major biomarker of acute myocardial infarction. Due to the presence of polyethylene glycol, the accuracy of the LFIA was improved significantly from a clear false positive signal to the absence of a false positive signal. In addition, the device exhibited a highly sensitive detection of cTnI in the concentration range of 1-90 ng mL(-1), and the detection limit can be as low as 10 pg mL(-1). The method further enabled the multiplex detection of cTnI and myoglobin successfully. It is anticipated that this work may open new paradigms for the development of a variety of lateral flow devices with high sensitivity and accuracy and further lead to widespread practical applications in clinical diagnosis.