Circulating tumor cells (CTCs) are tumor cells that originate from primary cancer tissues, enter the bloodstream in the body, and metastasize to the other organs. Simple and convenient methods for their detection, capture, and recovery from the blood of cancer patients would be highly desirable. We report here on a simple and convenient methodology to trap, culture, and re-collect cancer cells, the sizes of which are greater than those of normal hematologic cells, by the use of glass-bead filters (GBFs). We prepared GBFs with a diameter of 24 mm and thicknesses of 0.4 mm and 1.2 mm, with well-defined pores, by sintering round-shaped glass beads (diameter: 63-106 μm). A small integrated glass-bead filter (iGBF) with a diameter of ca. 9.6 mm for the use in filtering a small volume of blood was also designed and prepared. Using GBF and iGBF, it was possible to efficiently capture mouse Lewis lung carcinoma cells expressing green fluorescent protein spiked in saline/blood by single and repeated (circulation) filtrations in in vitro experiments with very small amounts of red blood cells being captured. In addition, we successfully captured B16 CTCs from the blood of a B16 melanoma metastasis mouse model by iGBF. Cancer cells/CTCs captured on/in the GBF could be cultured and efficiently recovered from the filters. Filtration by GBF had negligible effect on the adherent and proliferative characteristics of cancer cells. Simple and convenient methods for the capture, culture, and re-collection of CTCs by GBF along with flexibility of GBF, which permits them to be molded into suitable architectures having the desired shape and size, should be useful for early and convenient diagnosis and treatment of cancer and related diseases.
Keywords: circulating tumor cells; filtration; glass-bead filter; size-based separation.