Flow cytometric quantitation of EpCAM-positive extracellular vesicles by immunomagnetic separation and phospholipid staining method.

Extracellular vesicles (EV) have attracted attention as circulating biomarkers for many diseases, particularly cancer. Conventional immunofluorescence staining has been used for the detection of target antigens on EV by flow cytometry. However, the staining intensity depends on the amount of antigen expressed on the vesicles and is often only around the noise level.

Rapid phase change of lipid microdomains in giant vesicles induced by conversion of sphingomyelin to ceramide.

To understand the role of sphingomyelinase (SMase) in the function of biological membranes, we have investigated the effect of conversion of sphingomyelin (SM) to ceramide (Cer) on the assembly of domains in giant unilamellar vesicles (GUVs). The GUVs were prepared from mixture of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), N-palmitoly-D-erythro-sphingosine (C16Cer), N-palmitoyl-D-erythro-sphingosylphosphorylcholine (C16SM) and cholesterol. The amounts of DOPC, sum of C16Cer and C16SM, and cholesterol were kept constant (the ratio of these four lipids is shown as 1:X:1-X:1 (molar ratio), i.