Buoyancy-Activated Cell Sorting Using Targeted Biotinylated Albumin Microbubbles
Journal
PLOS ONE
Journal Volume
10
Journal Issue
5
Date Issued
2015-05
Author(s)
Abstract
Cell analysis often requires the isolation of certain cell types. Various isolation methods have been applied to cell sorting, including florescence-activated cell sorting and magnetic-activated cell sorting. However, these conventional approaches involve exerting mechanical forces on the cells, thus risking cell damage. In this study we applied a novel isolation method called buoyancy-activated cell sorting, which involves using biotinylated albumin microbubbles (biotin-MBs) conjugated with antibodies (i.e., targeted biotin-MBs). Albumin MBs are widely used as contrast agents in ultrasound imaging due to their good biocompatibility and stability. For conjugating antibodies, biotin is conjugated onto the albumin MB shell via covalent bonds and the biotinylated antibodies are conjugated using an avidin-biotin system. The albumin microbubbles had a mean diameter of 2μm with a polydispersity index of 0.16. For cell separation, the MDA-MB-231 cells are incubated with the targeted biotin-MBs conjugated with anti-CD44 for 10 min, centrifuged at 10g for 1 min, and then allowed 1 hour at 4°C for separation. The results indicate that targeted biotin-MBs conjugated with anti-CD44 antibodies can be used to separate MDA-MB-231 breast cancer cells; more than 90% of the cells were collected in the MB layer when the ratio of the MBs to cells was higher than 70:1. Furthermore, we found that the separating efficiency was higher for targeted biotin-MBs than for targeted avidin-incorporated albumin MBs (avidin-MBs), which is the most common way to make targeted albumin MBs. We also demonstrated that the recovery rate of targeted biotin-MBs was up to 88% and the sorting purity was higher than 84% for a a heterogenous cell population containing MDA-MB-231 cells (CD44+) and MDA-MB-453 cells (CD44-), which are classified as basal-like breast cancer cells and luminal breast cancer cells, respectively. Knowing that the CD44+ is a commonly used cancer-stem-cell biomarker, our targeted biotin-MBs could be a potent tool to sort cancer stem cells from dissected tumor tissue for use in preclinical experiments and clinical trials. © 2015 Liou et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
SDGs
Other Subjects
antibody; avidin; biotin; Hermes antigen; human serum albumin; albuminoid; Article; biotinylation; breast cancer cell line; buoyancy activated cell sorting; cell isolation; cell selection; cell separation; conjugation; controlled study; human; human cell; microbubble; metabolism; procedures; tumor cell line; Albumins; Antibodies; Biotinylation; Cell Line, Tumor; Cell Separation; Humans; Microbubbles
Type
journal article