Figure 2.

Overview of circulating tumor cell enrichment techniques. (A) Density-based CTC enrichment combines whole blood with density-gradient media such as Ficoll to separate based on cell density. Mononucleated cells including CTCs can then be recovered for further analysis; (B) Size-based CTC enrichment allows the smaller blood cells to pass through size restricted pores or channels while larger tumor cells are captured; (C) Immunomagnetic-based CTC enrichment either selects positively (for CTCs) or negatively (for white blood cells) using iron-labeled target antibodies; (D) Microfluidic-based CTC enrichment passes blood through either chip-based devices and/or antibody-coated micro-posts (depicted) to enrich CTCs from whole blood.