Highly efficient capture of circulating tumor cells with low background signals by using pyramidal microcavity array

This report demonstrates that a microfluidic device with integrated silicon filter exhibits outstanding capture efficiency and superior enrichment purity when employed to separate tumor cells from whole blood samples. We fabricate the silicon filter with pyramidal microcavity array (MCA) by microfabrication. We design the structure of the cavity to efficiently enrich tumor cells, while allowing hematologic cells to deform and pass through. The capture efficiency of MCF-7, SW620 and Hela cells spiked in 1 mL of whole blood are approximately 80%. Unwanted white blood cells (WBCs) trapped on the MCA are below 0.003%. In addition, this microfluidic device successfully identifies circulating tumor cells (CTCs) in 5 of 6 patients’ blood samples, with a range of 5–86 CTCs per mL. These results reveal that the disposable microfluidic device can effectively enrich tumor cells with different sizes and various morphologies, while maintaining high capture efficiency and purity. Therefore, this label-free technique can serve as a versatile platform to facilitate CTCs analysis in diverse biochemical applications. [Display omitted] •This pyramidal microcavity array can recover spiked tumor cells from the whole blood sample with >83% capture efficiency and 0.0015–0.003% background signals.•The microfluidic device utilizes only 1 mL of blood.•The blood sample does not require any pretreatment.•Trapped cells on the stiff silicon filter can be imaged and counted directly.