A Sensitive Aptasensor Based on a Hemin/G‐Quadruplex‐Assisted Signal Amplification Strategy for Electrochemical Detection of Gastric Cancer Exosomes

Abstract Emerging evidence indicates that exosomes derived from gastric cancer cells enhance tumor migration and invasion through the modulation of the tumor microenvironment. However, it remains a major problem to detect cancer‐specific exosomes due to technical and biological challenges. Most of the methods reported could not achieve efficient detection of tumor‐derived exosomes in the background of normal exosomes. Herein, a label‐free electrochemical aptasensor is presented for specific detection of gastric cancer exosomes. This platform contains an anti‐CD63 antibody modified gold electrode and a gastric cancer exosome specific aptamer. The aptamer is linked to a primer sequence that is complementary to a G‐quadruplex circular template. The presence of target exosomes could trigger rolling circle amplification and produce multiple G‐quadruplex units. This…