Enhancement of Capture Sensitivity for Circulating Tumor Cells in a Breast Cancer Patient's Blood by Silicon Nanowire Platform

The separation of circulating tumor cells (CTCs) from the blood of cancer patients with high sensitivity is an essential technique for selecting chemotherapeutic agents at a patient-by-patient level. Recently, various research groups have reported a nanostructure-based platform for rare cell capture due to its high surface area and 3D nanotopographic features. However, evaluation of capture sensitivity based on chemical modification of the nanostructure surface has not yet been performed. Here, we evaluated the capture sensitivity for CTCs from the blood of three patients diagnosed with stage IV metastatic breast cancer by using the following three platforms: streptavidin-conjugated silicon nanowire (STR-SiNW), poly-l-lysine-coated silicon nanowire (PLL-SiNW), and poly-l-lysine-coated glass (PLL-glass). The number of evaluated CTCs on STR-SiNW, PLL-SiNW, and PLL-glass were 16.2 +/- 5.5 cells, 7.3 +/- 2.9 cells, and 4.7 +/- 1.5 cells, respectively, per 0.5 ml. Therefore, we suggest that the STR-SiNW platform is highly adaptable for the quantitative evaluation of CTCs from the blood of cancer patients in the clinical setting.