Design and Simulation of an Automated Rare Blood Cell Detector

The use of circulating tumor cell (CTC) counts in cancer management has increased in recent years.  Detecting small numbers of rare cells in blood and monitoring the therapeutic progress, CTC detection technology currently plays an important role.  However, the detection is limited to specialized laboratories, requiring skilled technicians, with the length of the time for analysis making it difficult to detect disease at an early stage.

The objective of this research is to design, simulate and test an accurate, cost-effective, user-friendly point-of-care CTC detection device.  The preliminary design includes three syringes for sample, buffer and reagents, a static mixer, a magnetic filter, a microfluidic “chip” and a waste receptor.  The device is small, inexpensive and easy to operate.  The device is portable and can be used in clinics, nursing homes or residences allowing earlier and more convenient detection of most circulating cancer cells.

Recently our research focused on the analysis and simulation of the system as well as experimental work on the magnetic particle separation.  The fluid dynamic analysis of the static mixer was accomplished using the FLUENT^TM analysis package, modeling fluid flow and tracking particle movement in complex geometries.  The simulations of the magnetic separation step include the effects of the magnetophoretic mobility and gravity as well as the effect of hindered flow. 

The theoretical calculations and experimental work showed that the magnetic trap is able to capture all particles within the channel.  The test of static mixer showed the mixing pattern and properties of blood and reagents, and also included the effect of sedimentation during the process. Result showed that a 20-staged static mixer can provide adequate time for blood and reagents getting well mixed without the effect of sedimentation.  The results of the simulations will direct the optimization of the design of the static mixer and the magnetic filter.