Abstract
In this study, a centrifugal multilayer filter device is applied for particles and Circulating Tumor Cells (CTCs) separation. In recent years, many researches emphasize separating microparticles by using microfluid chips. Size-based separation is the most straightforward and common approach for microfluid based separation. However, the main disadvantage of size-based filtration encountered is clogging. The reason is that the concentration of particle sample is too high and the clogging will lead to reducing separation efficiency. In this study, a multilayer concentric filter device with different pore sizes combined with changing Revolution(s) Per Minute(RPM) instantly to generate cross-flow and reduce the phenomenon of particles clogging. We use the centrifugal filter device to separate microparticles and further apply this concept to CTCs detection. Tumor cells can be bounded by specific antibody coated with PS beads. The antibody has the ability to bind specific antigen on tumor cells .The conjugated size of CTCs and PS bead will become larger depending on how many tumor cells and PS beads bounded. The results show a significant clogging reducing with particle separation and the rare targeted tumor cells mixed with blood cells in the ratio of 1:1,000,000 are successful demonstrated. The centrifugal filter device was fabricated using photolithography and soft-lithography techniques. It is fabricated by regular PDMS modeling process. The advantages of biocompatible, low cost, disposable, and transparent of PDMS make, it fulfill with the requirements of useful microfluidic biochips. The centrifugal filter device and centrifuge used in this research are portable.