Specific Capture and Release of Circulating Tumor Cells Using Aptamer‐Modified Nanosubstrates

Abstract

Circulating tumor cells (CTCs)[1] are cancer cells that have propagated from tumors, spreading into the bloodstream as the cellular origin of fatal metastasis. Besides conventional diagnostic approaches (e.g., tumor biopsy, anatomical/molecular imaging and serum marker detection), detecting CTCs in peripheral blood is of prognostic value in different types of solid tumors, especially for predicting patient survival. The fact is that CTC detection have been technically challenging because of the extremely low abundance (a few to hundreds per mL) of CTCs among a high number (109 cells mL-1) of hematologic cells.[2] Over the past decade, a diversity of diagnostic technologies has been demonstrated for CTC detection using different working mechanisms. The current FDA-cleared CellSearch™ Assay is based on immunomagnetic separation of CTCs. Due to its unsatisfactory efficiency and high cost, researchers have been exploiting new technologies,[3] e.g., flow cytometry, size-based filtration systems and microfluidic devices that may offer improved sensitivity and reduced cost for CTC detection. In addition to the prognostic utility of CTC-based diagnostics, it is conceivable that the molecular signatures and functional readouts derived from CTCs will shed much valuable insight into tumor biology during the critical window where therapeutic intervention could make a significant difference.