Three-dimensional microfluidic chip with twin-layer herringbone structure for high efficient tumor cell capture and release via antibody-conjugated magnetic microbeads.

Harvesting rare circulating tumor cells (CTCs) from human blood is distinctly substantial to monitor tumor stage and evaluate therapeutic efficacy. As a proof-of-concept study, a microfluidic chip with twin-layer herringbone grooves was developed to isolate and recover tumor cells with high efficiency based on the immunoreaction between cells and antibody-conjugated microbeads (MBs) under local magnetic field. Functional MBs were initially localized onto the internal channel wall through the magnetic guidance. Then, infused tumor cells were deviated into the herringbone groove via passive microvortex and were further trapped through an irreversible interaction with MBs. Upon the removal of magnet, the captured cells and residual MBs were released from the channel and collected for further analysis in cell adhesion and proliferation in vitro. Capture efficiency of tumor cells reached up to ∼90% and limit of detection was down to 50 cells per mL based on this approach. Furthermore, recovery rate of tumor cells was as high as ∼94%, and potencies of cell attachment and proliferation was well maintained in retrieved cells. Hence, the present technique has a great potential for the isolation, quantitation and recovery of CTCs for cancer theranostic guidance and biomolecular analysis.