Surface Phenotype Mediated Detection Of NSCLC-derived Exosomes By SPRi Biosensing Assay

Exosomes have been reported to increase rapidly in blood circulatory system in non-small cell lung cancer(NSCLC).These vesicles transfer proteins and other biomolecules to recipient cells,thereby affecting the physiological conditions in disease.Plenty of these proteins are displayed on exosomal membrane,resulting in different amounts of surface phenotype.These phenotypes can help identify cell subtypes of exosomes,which further promote the diagnosis and treatment of NSCLC.Therefore,it is very imperative to establish a non-invasive,simple and highly specific biosensing detection method to facilitate the early diagnosis of NSCLC.In this study,a new biosensor based on the surface plasmon resonance imaging(SPRi)platform was constructed for highly sensitive,label-free and multi-component detection of exosomes.First,an antibodies microarray was modified on SPRi chip to capture exosomes by bioaffinity interaction of antibodies and different surface phenotypes.The SPRi signal primarily had a response,due to exosomes causing local refractive index changes.Then,by integrating functionalized AuNPs with outstanding effect of LSPR and high refractive index properties,amplification of SPRi signal was achieved.Under this circumstance,we can high-sensitively and multiply characterize NSCLC-derived exosomes.Our experiment revealed the abundance of EGFR and EpCAM in all tested NSCLC exosomes.It was also found that CD63 remained a moderate level and almost the same among the three kinds of NSCLC cell-derived exosomes.These are informative to provide promising molecular signatures associated with parent cells.Through this protocol,the exosomes derived from normal lung and NSCLC cells can be effectively distinguished via precise identification of the exosomes'protein pattern.And the distinction of exosomes derived from different NSCLC cells are also identified.Besides,the limit of detection of this SPRi-based biosensor is 2.37×10~4 particles/?L.The developed method was successfully applied in the determination of exosomes purified from clinical plasma samples,including healthy volunteers,the preliminary diagnostic NSCLC patients and NSCLC patients getting relief from treatment.This result suggested that is possible to screen NSCLC and evaluate the curative effect by detecting plasma-derived exosomes,demonstrating good clinical applicability of the SPRi biosensor.Thus,the constructed SPRi array has capacity of high sensitivity,multiplex and real-time for detecting exosomes.With the ability to analyze exosomes derived from NSCLC cells and evaluate protein expression levels,our method can identify the parental cell types of NSCLC-related exosomes to provide more help for the diagnosis,monitoring and treatment options of NSCLC.Consequently,this SPRi biosensing strategy will offer a potential tool for massive high-throughput screening for NSCLC in clinical specimens.