A nanostructured lateral flow immunoassay strip combined with Au@SiO2 SERS nanotags for multiplex biomarker detection

Blood biomarker detection can conveniently and non-invasively realize early diagnosis in asymptomatic people with Alzheimer's disease (AD). However, disease biomarkers have extremely low abundance; therefore, ultrahigh sensitive detection techniques are required, which are still a challenge. This research proposes a nanostructured lateral flow immunoassay strip combined with Au@SiO2 surface-enhanced Raman scattering (SERS) nanotags (nanostructured SERS-LFIA) for rapid and low-cost detection and to improve the sensitivity, replacing the conventional test line (T line) with inverse opal nitrocellulose. The nanostructured SERS-LFIA is used to detect AD biomarkers as a possible application in early diagnosis. Two AD biomarkers, Aβ42 and Aβ40, encoded by SERS nanotags are simultaneously detected on the same nanostructured T line, with a limit of detection (LOD) of 15.3 and 16.8 fg mL−1, respectively, about 10 times lower than that of SERS-LFIA. The nanostructured SERS-LFIA has great potential in the non-invasive detection of AD biomarkers and early diagnosis.