Fig 1.
Chip design and principle for exosome capture and detection.
(A) Schematic representation of the microfluidic chip. (B) Image of the chip. The scale bar represents 1 cm. (C) Workflow for the immunomagnetic capture and detection of exosomes.
Fig 2.
Verification of immunocapture of exosomes on the chip.
(A) MCF7 and M231 secreted exosomes were negatively stained using uranyl acetate and viewed by TEM. These exosomes showed typical cup-shaped morphology with diameters less than 100 nm. (B) TEM images of the immunomagnetic particles with. The arrow indicated two exosomes captured by a magnetic nanoparticle. (C) Western blot analysis of CD63, MHC I, and GAPDH expression in exosomes isolated from MCF7 culture medium and two plasma samples. (D) Quantification of total exosomes captured by Mag-CD63 from different volumes of M231 culture medium. A stable on-chip capture efficiency was demonstrated (R2 = 0.93). (E) Quantification of total exosomes captured by Mag-CD63 from different volumes of human plasma sample. A stable on-chip capture efficiency was demonstrated (R2 = 0.995). The scale bars represent 100 nm in (A-B) and 50 μm in (D-E).
Fig 3.
Microfluidic immunomagnetic capture and detection from cell culture medium.
(A) Images and quantification of total exosomes from control and CM of NF, MCF7 and M231. Exosomes were stained by PKH67. (B) Images of and quantification of MHC I-positive exosomes from control and CM of NF, MCF7 and M231. *, p< 0.05. The scale bars represent 50 μm.
Fig 4.
Quantification of EpCAM-positive exosomes from breast cancer cell lines and clinical patients.
(A) Images and quantification of captured EpCAM-positive exosomes from Ctr, NF, MCF7 and M231 culture medium. (B) Images of and quantification of captured EpCAM-positive exosomes from plasma samples of breast cancer patients (6 cases) and healthy controls (3 cases). *, p< 0.05; **, p< 0.01. The scale bars represent 50 μm.
Fig 5.
Quantification of HER2-positive exosomes from breast cancer cell lines and clinical patients.
(A) Images and quantification of captured HER2-positive exosomes from Ctr, NF, MCF7, M231 and SK-BR-3 culture medium. (B) Images and quantification of captured HER2-positive exosomes from plasma samples of breast cancer patients with different HER2 expression in primary tumor tissues. HER2+, 6 cases; HER2++, 9 cases; HER2 +++, 3 cases.*, p< 0.05; **, p< 0.01. The scale bars represent 50 μm.