Efficient isolation and sensitive quantification of extracellular vesicles based on an integrated ExoID-Chip using photonic crystals

Extracellular vesicles (EVs), involved in many diseases and pathophysiological processes, have emerged as potential biomarkers for cancer diagnose. However, efficient isolation and detection of EVs still remain challenging. Here, we reported an integrated chip for isolation of EVs with double-filtration unit and ultrasensitive detection using photonic crystals (PC) nanostructure. The nanofiltration membranes were integrated to the device to isolate and enrich the EVs of 20–200 nm in size based on size-exclusion. Then CD63 aptamers were used to combine the EVs on the nanofiltration membrane with a pore size of 20 nm, and excess aptamers passed through the membrane to bind with CD63 immobilized on the PC nanostructure. Benefitting from the fluorescence enhancement effect of PC nanostructure in the competition assays, the EVs could be quantified sensitively by analyzing the concentration of excess aptamers. Due to the high sensitivity, the limit of detection was as low as 8.9 × 103 EVs/mL with low sample consumption of only 20 μL. Furthermore, serum samples from breast cancer patients and healthy donors could be successfully distinguished. Thus, this microfluidic chip provides an effective method for prescreening of cancer in clinical samples.