Highly EfficientIsolation and Rapid Detection ofPancreatic Cancer-Derived Small Extracellular Vesicles by SpecificAggregation from Aptamer-Functionalized DNA Long Chains

Small extracellular vesicles (sEV) are increasingly reported as biomarkers for the early diagnosis of pancreatic cancer (PC), but the current techniques for isolation and detection of sEV rely on expensive instruments and tedious protocols. In this work, a facile and rapid sEV isolation and detection method (LAPT-sEViso) was developed, which is based on the specific aggregation of GPC-1-positive PC-derived sEV and an aptamer-functionalized DNA long chain produced by rolling circle amplification (RCA-APT). The LAPT-sEViso can efficiently isolate sEV from cell culture medium and serum, showing 45 times higher yield (5.5 × 106 particles mL-1), 1.1 times higher purity (1.66 × 1010 particles mg-1) and 4.9 times higher recovery (80.9%) comparing to the traditional ultracentrifugation method, with only $1000 common instruments and $2.88 reagents/materials in 1 h. Moreover, after simple filtration and on-membrane ELISA, sEV concentration can be instrument-free detected with a limit of detection of 5.62 × 103 particles μL-1 (linear range from 5.0 × 103 to 5.0 × 107 μL-1). The LAPT-sEViso provides an efficient and practical approach for the rapid isolation and detection of sEV, providing a novel approach for the sEV-based liquid biopsy.