Nano "fly paper" technology for the capture of circulating tumor cells

Some efficient diagnosis and therapy systems require the isolation and quantification of circulating tumor cells (CTCs), since these species are important "biomarkers" for monitoring cancer metastasis and prognosis. Existing techniques for isolating/counting CTCs include immunomagnetic-bead-based separation and microfluidic capture. However, some of these techniques have low capture efficiency and low specificity. Through the use of a three-dimensional (3D) nanostructured substrate - specifically, a silicon-nanowire (SiNW) array coated with epithelial-cell-adhesion-molecule antibodies (anti-EpCAM) - we show that CTCs can be captured efficiently and specifically. Unlike conventional methods for isolating CTCs that depend on collision frequency and contact duration, nanoscaled local topographic interactions between the CTCs and the substrate increase their binding and markedly enhance capture efficiency.