Ultra-fast CTC enrichment

Circulating tumor cells (CTCs) are valuable biomarkers of disease and accessible through minimally invasive liquid biopsy methods, such as a simple blood draw. Unfortunately, the isolation, detection and analysis of CTCs is immensely challenging due to their extremely low abundance in whole. Indeed, only 1-10 CTCs are typically present in 1 mL of blood and are hidden by a background of billions of red blood cells, white blood cells and platelets. Currently, the CellSearch® instrument is the only FDA-approved system for CTC-based clinical applications. CellSearch® leverages immunomagnetic enrichment to detect CTCs, but suffers from low sensitivity and high background signals, preventing accurate downstream analysis. In principle, fluorescence-activated cell sorting (FACS within microfluidic formats have thus emerged as a powerful tool leveraging immunofluorescence staining to efficiently separate, isolate and enrich CTCs.

Recently, Yingchao Meng and colleagues from the deMello lab introduced the high-throughput microfluidic rare-cell sorter (μRCS) for enriching CTCs from whole blood. The platform overcomes the limitations of both commercial and microfluidic-based FACS instruments by combining 10 parallel micro-channels equipped with pneumatic valves with real-time fluorescence detection. This system uses an aliquoting approach to enrich CTCs and not only operates at a high throughput of 0.5mL/min but also maintains cell viability above 95%. Significantly, clinical blood samples can be enriched by nearly eight orders of magnitude after three rounds of sorting, with purity and recovery rates matching or exceeding those of CellSearch® system.

Written by Magali Ledoigt

Read the published article here.