Development and optimization of surface-enhancement Raman scattering-based lateral flow immunoassays for the ultrasensitive detection of cardiac troponin I

Cardiac Troponin I is measurable using point-of-care testing (POCT) and lateral flow assay (LFA) for diagnosing acute myocardial infarction (AMI) in a clinical method that combines the advantages of cost-effectiveness, rapid detection, and ease of use. However, the limitation of LFA is that it hinders the diagnosis of patients with a low analyte concentration, necessitating additional blood tests. Surface-enhancement Raman scattering (SERS)-based LFA can provide the quantitative assay with high sensitivity. This study reports a straightforward process for developing SERS-based LFA that detected 0.02 ng/mL analyte in human serum compared to the 1.56 ng/mL analyte detected using optical intensity measurement in LFA. To ensure highly sensitive detection, the size (30 to 100 nm) of Au nanoparticle (NP) in SERS tags was optimized in SERS-based LFA, and a stronger SERS intensity was achieved using 50 nm AuNP SERS tags. The reaction time and LFA buffer components were determined, and laser wavelength and power were investigated. By optimizing these parameters for SERS-based LFA, the sensitivity of SERS was 78-fold higher than that of optical intensity measurement. This procedure could be beneficial for developing a SERS-based LFA to detect various biomarkers with high sensitivity for potential POCT applications.