SOI technology-based microfiltration system for circulating tumor cells isolation and enumeration

A SOI technology-based micro filtration system for circulating tumor cells (CTCs) isolation and enumeration is reported; this is in contrast of using single-crystal-silicon wafers resulting in poor etching uniformity. This microsystem consists of a silicon filter enclosed with PDMS layers, a digital syringe pump, a fluorescence microscope, a digital CCD camera in combination with the CellProfiler software for rapid cell enumeration. Human cervical cancer cells (HeLa cells) were used for preliminary tests of the system performance. 3D CFD simulations demonstrate that the velocity and shear stress can be well controlled to avoid hydrodynamic cell lysis. In comparing with our previous CTC chip using polycarbonate (PC) filter membrane, the SOI-based system has a much improved CTC capturing and enumeration performance.