Based lateral flow immunosensor for ultrasensitive and selective surface-enhanced Raman spectroscopy stroke biomarkers detection

Schematic illustration of the SERS tags-based multiplex lateral flow lateral flow assay devices. • Compared with traditional methods, our developed method do not need any treatment and additional chemicals. • Due to using nano-probes spectroscopy, our developed method can detect tiny blood. • Compared with traditional methods, our developed method have advantages of time-saving. • SERS lateral flow assay (LFA) integrated fiber-optic biosensor was realized for the first time for in situ stroke immunoassay in unprocessed whole blood. Despite optimistic trends in mortality and incidence, stroke is still a major cause of disability and death in populations. The application of blood-based biomarkers is known as a promising field for predicting the disease severity and prognosis to further guide therapy strategy. However, proposing a method that can accurately and sensitively identify patients by biomarkers detection remains a notable challenge due to the complexity of stroke pathogenesis and low abundance of target molecules. In this experiment, we designed a target antibody modified surface-enhanced Raman scattering (SERS) active nanospheres (GNPs) combined with probe-immobilized lateral flow strip as nanostructure to assess multiple-biomarker in blood samples of stroke patients simultaneously. Then the sensitive and quantitative measures toward stroke-related matrix metalloproteinase-9 (MMP-9), S100 calcium-binding protein B protein (S100-β), and neuro-specific enolase (NSE) were implemented in a wide range from 0.0001 ng/mL to 1000 ng/mL and a limit of detection of 0.01 pg/mL. Furthermore, the accuracy of SERS imaging was detected by enzyme linked immunosorbent assay (ELISA); the outcome obtained through SERS imaging was in accord with those obtained by ELISA. Therefore, this method can provide a reliable strategy for stroke diagnosis and prognosis evaluation with showing great prospect for clinical applications through further quantitative analysis of molecules in blood samples.