Abstract
OBJECTIVE: To construct a magnetic and catalytic hairpin assembly-based platform for detection of dual membrane proteins on exosomes. METHODS: Exosomes in supernatant of breast cancer MDA-MB-231 cell culture were separated, purified and characterized. Super-resolution imaging and Western blotting were performed to confirm the expression of the membrane protein CD63 on the exosomes. Polyacrylamide gel electrophoresis was used to verify the combination of Apt(EpCAM)-T and exosomes. Fluorescence experiments were carried out to test the feasibility of CHA nucleic acid sequence, optimize the reaction conditions, and determine the specificity of the detection platform. RESULTS: Super-resolution imaging and Western blotting showed that breast cancer MDA-MB-231 cell-derived exosomes expressed abundant membrane protein CD63. Polyacrylamide gel electrophoresis indicated that Apt(EpCAM)-T could recognize and bind to exosomes. The results of specificity test showed that the signal-to-noise ratio of the detection platform was 1.10±0.01 for detecting normal human breast epithelial cell-derived exosomes, and was 2.09±0.08 for breast cancer cell-derived exosomes. CONCLUSIONS: Magnetic and catalytic hairpin assembly-based detection platform allows simultaneous detection of two membrane proteins expressed on exosomes and identification of the expressions of membrane proteins on exosomes from different sources.