"Sample-in, result-out" liquid biopsy chip based on immunomagnetic separation and CRISPR detection for multiplex analysis of exosomal microRNAs.

Multiplex analysis of exosomal microRNAs (miRNAs) plays an important role in noninvasive early disease diagnosis. However, the complexity of the testing process has hindered its clinical application. Here, we proposed an integrated chip for the detection of eight exosomal miRNAs in serum which can achieve "sample in, result out" detection. We developed an immunomagnetic isolation system based on CD63 aptamers (IISA) for separation of serum exosomes. The system was combined with immiscible filtration assisted by surface tension (IFAST) to remove impurities. Bubble mixing was applied to ensure adequate binding or cleavage of exosomes to magnetic beads. CRISPR detection technology was utilized to allow for effective detection of seven hepatocellular carcinoma (HCC)-related miRNA targets. Based on the test of clinical samples, the chip can achieve 78 % exosome capture efficiency and 55 % recovery, and simultaneously detect eight targets within 1 h. This chip could be applied as a robust and cost-effective tool for cancer diagnosis and monitoring of cancer stages.