Isolation of circulating tumor cells using a microvortex-generating herringbone-chip

Abstract

Rare circulating tumor cells (CTCs) present in the bloodstream of patients with cancer provide a potentially accessible source for detection, characterization, and monitoring of nonhematological cancers. We previously demonstrated the effectiveness of a microfluidic device, the CTC-Chip, in capturing these epithelial cell adhesion molecule (EpCAM)-expressing cells using antibody-coated microposts. Here, we describe a high-throughput microfluidic mixing device, the herringbone-chip, or “HB-Chip,” which provides an enhanced platform for CTC isolation. The HB-Chip design applies passive mixing of blood cells through the generation of microvortices to significantly increase the number of interactions between target CTCs and the antibody-coated chip surface. Efficient cell capture was validated using defined numbers of cancer cells spiked into control blood, and clinical utility was demonstrated in specimens from patients with prostate cancer. CTCs were detected in 14 of 15 (93%) patients with metastatic disease (median = 63 CTCs/mL, mean = 386 ± 238 CTCs/mL), and the tumor-specific TMPRSS2-ERG translocation was readily identified following RNA isolation and RT-PCR analysis. The use of transparent materials allowed for imaging of the captured CTCs using standard clinical histopathological stains, in addition to immunofluorescence-conjugated antibodies. In a subset of patient samples, the low shear design of the HB-Chip revealed microclusters of CTCs, previously unappreciated tumor cell aggregates that may contribute to the hematogenous dissemination of cancer.

Engineering fluid flow using sequenced microstructures

“…Rotating or moving fluid streams to be analysed away from walls to regions of uniform downstream velocity at the channel centre can minimize Taylor dispersion 9 , bring fluid into a small focal spot for optical interrogation 31,32 or reduce fouling and adhesion to channel surfaces. Conversely, bringing fluid to narrow slow moving regions near channel walls can enhance surface reactions (for example, immunoassays 33 ), or aid in affinity capture of cells 34 or molecules. Additionally, utilizing this platform to deterministically guide liquid in microchannels can enhance heat transfer, especially in electronic cooling, by maximizing the efficiency of coolant usage near hot spots and enabling the usage of larger channels with lower pressure drops and power consumption in these systems [35][36][37] .…”

Rare cell isolation and profiling on a hybrid magnetic/size-sorting chip

“…Unlike a simple laminar flow, the chaotic advection brings cells more frequently in contact with the channel bottom, enhancing the capture efficiency by the magnetic filter. 28,29 The channel height, therefore, is no longer limited by the reach of the magnetic field into the flow channel, and tall channels could be implemented to increase the throughput while reducing fluidic resistance. Second, the structural strength of the size-sorter is reinforced by embedding a thin glass slip in the channel top ( Fig.…”

Modeling of cell sorting and rare cell capture with microfabricated biodevices

“…Furthermore, most metastases are thought to arise from cells that escape from the primary tumor and then transiently circulate in the cardiovascular system as CTCs [10]. Although very important in basic research and clinical diagnostics, the detection and capture of these cells is a great challenge because the typical number of CTCs in the blood range from one (if any) CTC per 10 ml up to several hundreds of CTCs per ml [8,11]. Biomarkers on the cancer cell surface or inside the cell are not abundant either [12].…”