Multilegged Exosomal Walker for Electrochemical Detection of Exosomes

Detection of exosomes has aroused great interests due to their intrinsic advantages in liquid biopsy for tumor diagnosis and treatment monitoring. Researchers from Fujian Medical University developed a cascade amplified electrochemical biosensor based on multilegged exosomal walkers for the sensitive and selective detection of exosomes. First, the exosomes were captured specifically by its membrane protein’s aptamer and fabricated into multilegged exosomal walkers with a large amount of cholesterol-labeled DNA strands plunging into their lipid bilayers. After being released efficiently by lock nucleic acid (LNA)-modified DNA strands complementary to the aptamers, the walkers were propelled by toehold mediated strand displacement reaction (TMSDR) and “walked” efficiently along DNA “track”, introducing considerable signal molecules attached on the “track” and achieving sensitive exosomes detection with a low limit of detection (LOD) of 29 exosomes/μL. Owing to excellent discriminative capability enhanced by LNA and TMSDR, the method possesses high selectivity toward tumor and nontumor cells derived exosomes, even for the serum exosomes from cancer patients in different stages. Furthermore, the designed biosensor is reproducible. Overall, this approach provides the potential to promote the large-scale development of liquid biopsy technology with exosomes as biomarkers.