Effective capture of cancer cells from whole peripheral blood samples, i.e. circulating tumor cells (CTCs), is still anexisting limitation for liquid biopsy-based diagnostics. The well-established closed-channel herringbone micro-mixersare one of the widely adopted methods for isolating CTCs based on antigen-antibody interaction. However, they areknown to be associated with several drawbacks, such as limited capture areas within the channels, restricted access toisolated cells, difficulties to achieve multiplexed antibody capture assays for immuno-phenotyping, and limited postprocessingpossibilities. To tackle these issues, we developed a novel microfluidic probe (MFP) that is integrated withherringbone micro-mixers on its tip surface (HMFP). The tip surface was designed with 2-slitted apertures, one forinjecting the cell suspension and the other for performing high flow rate aspiration to confine the flow. The herringbonemixing elements were distributed in-between the apertures for micro-mixing that enhances the CTCs capture on theantibodies-coated bottom glass surface. Unlike the closed herringbone chips, the functionalized bottom glass surface waskept large given the capacity for the MFP to work in scanning mode, and so it prevented cell capture saturation effect.Our MFP design and experimental setup showed a cell capture efficiency of 59-81% with flow rates of 0.6-2.4 mL/h.The capture of CTCs in an open microfluidic system allows for easy post-process and CTC analysis, such as single celldrug testing and mechano-phenotyping using atomic force microscopy.
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