SIMULATION AND MEASUREMENT OF FLOW FIELD IN MICROCHIP

Cancer(malignant tumor)is one of the serious threats to human life,causing 13%of all human deaths.A crucial step in the metastasis cascade of cancer is hematogenous spreading of tumor cells from a primary tumor.Thus,isolation and identification of cells that have detached from the primary tumor and circulating in the bloodstream(circulating tumor cells,CTCs)is considered to be a potential alternation to detect,characterize,and monitor cancer.Current methods for isolating CTCs are limited to complex analytic approaches that generate very low yield and purity.Here,we propose a high throughput 3D structured microfluidic chip integrated with surface plasmon resonance(SPR)sensor to isolate and identify CTCs from peripheral whole blood sample.The microfluidic velocity-field within the channel of the chip is mediated by an array of microposts protruding from upper surface of the channel.The height of microposts is shorter than that of the channel,forming a gap between the microposts and the lower surface of the channel.The lower surface of the channel also acts as the SPR sensor which can be used to identify isolated CTCs.Microfluidic velocity-field under different parameters of the arrayed microposts is studied through numerical simulation based on finite element method.Measurement on one of such fabricated microchips is conducted by our established optical Doppler tomography technique benefiting from its noninvasive,noncontact,and high-resolution spatialresolved capabilities.Both simulation and measurement of the microfluidic velocity-field within the structured channel demonstrates that it is feasible to introduce fluidic mixing and causes perpendicular flow component to the lower surface of the channel by the 3D structured microposts.Such mixing and approaching capabilities are especially desirable for isolation and identification of CTCs at the coated SPR sensor.