看到一篇Annexin A5包被的磁珠来捕获extracellular vesicles

大鹏子

最近看到一篇利用Annexin A5包被的磁珠来捕获plasma中的extracellular vesicles，觉得很惊奇
Shih C L, Chong K Y, Hsu S C, et al. Development of a magnetic bead-based method for the collection of circulating extracellular vesicles[J]. New Biotechnology, 2015.
文章的三个Highlights如下
Apoptotic bodies captured by ANX-beads contained both DNA and amplifiable RNA.
Plasma EVs can be captured with ANX-beads.
Tumor-derived EVs could be found in body fluids.
文章中解释Annexin A5 与膜表面的磷酯酰丝氨酸结合，用Annexin A5捕获凋亡小体可以理解，但是其他EVs的表面也有外露的磷酯酰丝氨酸吗？？？

本人小白一枚，求大神解惑