Chemically-Modified Sepharose 6B Beads for Collection of Circulating Tumor Cells

The isolation and quantitative characterization of circulating tumor cells (CTCs) are of great importance in cancer diagnosis and prognosis. However, isolating and detecting CTCs in whole blood presents a significant challenge due to the low numbers of CTCs (often ranging from one to five) in samples containing billions of erythrocytes. Recently, point-of-care devices that use antibody trapping coupled with remote immunofluorescence analyses have been described to identify the number and type of CTCs in blood. In this study, we propose a novel method for trapping and quantifying CTCs using Sepharose 6B beads of 45-160 μm size that are engineered with capture antibodies. Specifically, we employed CD44 antibody conjugates (bearing a maleimide group) that are specific to the CTCs of breast cancer to thiol-Sepharose beads 6B. These beads, when mixed with MDAMB231 and Jurkat cells and filtered through a 40 μm filter, can capture ~80% of MDAMB231 cells. Furthermore, the antibody-modified Sepharose 6B can be stored at four degrees Celsius for a period exceeding six months.