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, and the detection limit can be as low as 10 pg mL. 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.