A microfluidic device for rare cells trapping by adaptable ferromagnetic structures

This paper presents a new approach for a magnetic immunoassay-based lab-on-a-chip device, designed for enrichment of rare cells, particularly aimed to increase the isolation rate of circulating tumor cells (CTCs) in peripheral blood samples. The detection and early analysis of CTCs play important roles in diagnosis and treatment for cancer patients. Due to the extremely rare existence of CTCs compared to other blood cells, highly sophisticated selection methods must be developed. The separation of rare cells from a mixture of other cells is performed in two steps in our device. First, under an external magnetic field, an array of self-assembled structures formed by magnetic beads is built inside a microfluidic channel, acting as an adaptable trapping net for targeted cells. Secondly, the mixed cell suspension is flushed inside the device where only targeted cells are trapped by specific antibody-antigen bindings. The modifiable and controllable shapes of the trapping structures, may bring the device in broader applications suitable for different rare cell types of various morphologies. The microfluidic device is going to be built mainly by easy handling materials, such as polydimethylsiloxane (PDMS) on a master SU-8 mold and by standard microfabrication techniques, such as photo lithography and physical vapor deposition. Therefore, it can be realized in a high throughput and as a disposable platform. This paper focuses more on the simulation models. A preliminary sub-millimeter size prototype will also be briefly presented.