摘要
The lateral flow immuno assay (LFIA) has emerged as a powerful tool for rapid scree ning owing to its simplicity and flexibility for detection of various biomarkers. However, conventional LFIA strips have several disadvantages, including limits in quantitative analysis and low sensitivity. Here we developed a novel surface-e nhanced Rama n scatteri ng LFIA based on non spherical gap-e nhanced Raman tags (GERTs), with Raman molecules (RMs) embedded in a 1-nm gap between Au nanorod core and Au shell. Such tags have a strong and uniform surface-enhanced Rama n scattering (SERS) resp on se, an order of mag nitude higher than that of other comm on SERS tags such as Au nano rods, nano stars, Au nano shells with surface-adsorbed RMs, or spherical GERTs with embedded RMs. The feasibility of the tags was dem on strated by the semiqua ntitative and sen sitive detecti on of the heart disease biomarker cardiac tropo nin I (cTnI). GERTs were conjugated with mono clonal antibodies and used for LFIA in the same way as ordinary functionalized colloidal gold. The presenee of the target antigen, cTnI, was identified by Raman microscopy mapping of the test zone. With the SERS-based LFIA, the limit of cTnI detection was about 0.1 ng/mL. This value is within the diagnostic range of cTnI in the blood serum of patients with heart infarction and is 30 times lower than that of the colorimetric LFIA test using the same antibodies and either GERTs or colloidal gold as labels.
