Fig. 1

Characterization of EVs from maternal plasma. (a) Transmission electron microscope detection of EVs separated by SBI ExoQuick kit, showing typical cap-shaped morphology of exosomes (arrows). Scale bar = 200 nm; (b) Western blot analysis for the classical biomarker of exosomes (CD9, CD63 and CD81) and placenta specific biomarker (PLAP). Endoplasmic reticulum marker calnexin was used as a control marker, EV1-EV8 are exosomes from eight maternal plasma samples; human acute lymphatic leukemia cells (1301) was used as PLAP negative control and placenta villa cells was used as a PLAP positive control; (c) Flow cytometry detection for EVs from eight maternal plasma samples, showing the presence of CD63 marker in the EVs enriched from the total EVs with CD9 magnetic beads. FSC-SSC scatter plot of particles on the top right corner indicates that the instrument parameters were normal. (d) Examples of Q-PCR of evDNA from a male pregnancy and a female pregnancy to prove the presence of fetal originated evDNA. Large autosome (LA) DNA and small autosome (SA) DNA signal show the existence of template while Y chromosome DNA signal (Y) shows fetal gender, internal PCR control (IPC) is a system reference signal. (e) The ratio of cfDNA to evDNA from equal volume plasma (250 μl) was calculated according to the △Ct value in the Q-PCR experiment, which shows that in all 20 samples (“M” represents male pregnancy; “F” represent female pregnancy) cfDNA has higher level than evDNA with 2.8–61.5 of relative fold changes