Development point-of-care based lateral flow biosensor for the rapid detection of exosomes of subarachnoid hemorrhage patients†

Exosomes are extracellular vesicles with diameters ranging from 30–200 nm, and the biomolecules contained in exosomes have been used as biomarkers for the diagnosis and prognosis of certain diseases. Despite their increasingly recognized relevance as biomarkers, traditional strategies to achieve simple, sensitive, and accurate detection of exosomes remain a challenge due to the limitations of cumbersome separation and analysis of exosome-containing samples. We successfully developed a new lateral flow assay (LFA) for accurate quantification of plasma-derived exosomes in patients with subarachnoid hemorrhage (SAH). In this study, based on an ultrasensitive and simple surface-enhanced Raman scattering (SERS) strategy, we accurately captured membrane proteins in exosome samples by preparing 4-MPA antibody-modified Au–Ag nanoshuttles (Au–Ag NSs) as SERS probes on LFA strips to achieve dual detection of target proteins. The strategy had good stability and sensitivity with the limit of detection (LOD) of 0.7 × 10⁴ particles per mL for CD9 and CD81. Regarding our findings of LFA using Au–Ag NSs, this platform can be used as a tool for accurate, rapid and real-time exosome detection with high sensitivity and quantification.