Novel, Highly Sensitive, and Specific Assay to Monitor Acute Myocardial Infarction (AMI) by the Determination of Cardiac Troponin I (cTnI) and Heart-Type Fatty Acid Binding Protein (H-FABP) by a Colloidal Gold-Based Immunochromatographic Test Strip

Abstract

Acute myocardial infarction (AMI) is considered to be one of the predominant causes of human death; Therefore an early and accurate diagnostic method of AMI is urgently required. In this work, a novel colloidal gold-based immunochromatographic test strip was designed and fabricated for the combined determination of cardiac troponin I (cTnI) and heart-type fatty acid binding protein (H-FABP) for the diagnosis of AMI with high sensitivity and specificity. Colloidal gold particles (AuNPs) were synthesized through the reduction of gold chloride with sodium citrate, followed by conjugation with coating antibodies of cTnI or H-FABP by electrostatic interaction. The resultant conjugates were used as the instant visual signals and capture antibodies of cTnI and H-FABP were used as the test lines. Using a small sample volume (70 µL) and short detection time (10 min), the fabricated test strips exhibited excellent detection performance including a wide linear range and good accuracy and precision with no cross-reactivity. Moreover, the test strips were applied for different sample types such as serum and plasma, offering great convenience for clinical use. Additionally, the clinical samples were used to demonstrate the excellent validation of the test strips. The successfully combined determination of cTnI and H-FABP afforded the test strips with early diagnosis and enlarged the diagnosis window for AMI with other advantages such as low cost and user-friendliness. Hence, we believe that the test strips fabricated in this work have great potential to be applied for the early and accurate diagnosis of AMI in practical clinics.