Figure 5.

Positive-affinity microfluidic selection. (A) Assembly of the silicon CTC chip, SEM of a pseudo-coloured cell isolated on the Ab-coated micropillars, and simulated fluid velocity field in the device.³⁶ (B) The GEDI device arranges micropillars to hydrodynamically induce a strong bias towards recovering cells >15–18 μm (blue) and minimizing smaller WBC (yellow) interactions.⁴⁹ (C) The herringbone chip uses convective mixing to encourage CTCs to interact with Ab-coated surfaces.⁶⁵ (D) A schematic of the silicon nanopillar chip, where a convective mixing chamber is attached to a nano-textured, Ab-coated Si substrate.¹²⁸ (E) Polyurethane tubing is nano-textured with naturally occurring halloysite nanotubes and coated with Abs and selectins.²⁶² (F) The thermoplastic-based sinusoidal chip uses narrow, Ab-coated microchannels to isolate CTCs.²⁴ CTC release^34,125 enables off-chip enumeration and viability testing by an impedance sensor and a microfluidic imaging module,⁷⁴ which are integrated to a fluidic motherboard. Figure panels reproduced from reference³⁶ with permission from Nature Publishing Group, copyright 2007; reference¹²⁸ with permission from Wiley, copyright 2011; and reference⁷⁴ with permission from American Chemical Society, copyright 2013.