Key Laboratory of Process Monitoring and System Optimization for Mechanical and Electrical Equipment in Fujian Province, Huaqiao University, Xiamen, China.
Department of Mechanical Engineering, Chung Yuan Christian University, Chung Li District, Taoyuan City, Taiwan.
PLoS One. 2018 Jun 22;13(6):e0199438. doi: 10.1371/journal.pone.0199438. eCollection 2018.
Cancer cells secrete many exosomes, which facilitate metastasis and the later growth of cancer. For early cancer diagnosis, the detection of exosomes is a crucial step. Exosomes exist in biological fluid, such as blood, which contains various proteins. It is necessary to remove the proteins in the biological fluid to avoid test interference. This paper presented a novel method for exosome isolation using Fe3O4 magnetic nanoparticles (MNPs), which were synthesized using the chemical co-precipitation method and then coated with polyethylene glycol (PEG). The experimental results showed that the diameter of the PEG-coated Fe3O4 nanoparticles was about 20 nm, while an agglomerate of MNPs reached hundreds of nanometers in size. In the protein removal experiments, fetal bovine serum (FBS) was adopted as the analyte for bioassays of exosome purification. PEG-coated Fe3O4 MNPs reduced the protein concentration in FBS to 39.89% of the original solution. By observing a particle size distribution of 30200 nm (the size range of various exosomes), the exosome concentrations were kept the same before and after purification. In the gel electrophoresis experiments, the bands of CD63 (53 kDa) and CD9 (22 kDa) revealed that exosomes existed in FBS as well as in the purified solution. However, the bands of the serum albumins (66 kDa) and the various immunoglobulins (around 160 ~ 188 kDa) in the purified solution's lane explained that most proteins in FBS were removed by PEG-coated Fe3O4 MNPs. When purifying exosomes from serum, protein removal is critical for further exosome investigation. The proposed technique provides a simple and effective method to remove proteins in the serum using the PEG-coated Fe3O4 MNPs.
癌细胞会分泌许多外泌体，这些外泌体有助于转移和癌症的后期生长。为了进行早期癌症诊断，对外泌体的检测是至关重要的一步。外泌体存在于生物体液中，如血液，其中包含各种蛋白质。为了避免测试干扰，有必要去除生物体液中的蛋白质。本文提出了一种使用 Fe3O4 磁性纳米粒子（MNPs）分离外泌体的新方法，该方法是通过化学共沉淀法合成的，然后用聚乙二醇（PEG）进行涂层。实验结果表明，PEG 涂层的 Fe3O4 纳米粒子的直径约为 20nm，而 MNPs 的团聚体尺寸达到数百纳米。在蛋白质去除实验中，胎牛血清（FBS）被用作外泌体纯化的生物分析物。PEG 涂层的 Fe3O4 MNPs 将 FBS 中的蛋白质浓度降低到原始溶液的 39.89%。通过观察粒径分布在 30200nm（各种外泌体的尺寸范围），可以发现纯化前后外泌体的浓度保持不变。在凝胶电泳实验中，CD63（53kDa）和 CD9（22kDa）的条带表明外泌体存在于 FBS 以及纯化溶液中。然而，在纯化溶液条带中血清白蛋白（66kDa）和各种免疫球蛋白（约 160~188kDa）的条带表明，PEG 涂层的 Fe3O4 MNPs 去除了 FBS 中的大多数蛋白质。在从血清中纯化外泌体时，去除蛋白质对于进一步的外泌体研究至关重要。该技术为使用 PEG 涂层的 Fe3O4 MNPs 从血清中去除蛋白质提供了一种简单有效的方法。
