(334e) Magnetic Capture of Melanoma Cells From Whole Blood

            One in six Americans develops skin cancer, accounting for one third of all cancers in the United States.  Melanoma is most dangerous and causes the majority (75%) of deaths related to skin cancer.  In recent years the use of circulating tumor cell (CTC) counts in cancer management has increased.  With the ability to detect small numbers of rare cells in blood and to non-invasively monitor therapeutic progress, the developing CTC detection technology would play an important role.  However, the current detection process is expensive and lengthy and can only be accomplished in specialized laboratories requiring skilled technicians.  A point-of-care CTC detection device that is both accurate and affordable would greatly improve early cancer detection. 

            Recent advances in magnetic cell selection have enhanced the possibility of isolating cells of interest.  A point-of-care (POC) portable rare cell analyzer a three-stage magnetic trap for magnetically labeled rare cells was designed and tested.  The blood sample is mixed with reagents and buffer and then passed through a magnetic trap consisting of a flow channel with three bends and a permanent magnet positioned at the outer curve of each bend.  Findings are reported on the computational fluid dynamic analysis of the design, testing with model commercial magnetic beads used in cell labeling, and testing with immunomagnetically labeled cultured melanoma cells in the presence of whole blood.  The measurements of field profiles of the magnets were used to determine forces applied as a function of position in the trap.  Testing with 3.27 micron diameter standard magnetic beads (Seragen) indicated that at least 99.998% of these strongly magnetic particles are captured within the trap, most in the first stage.  Testing with cultured CRL14777 melanoma cells labeled with anti-CD146 1.5 μm diameter beads indicated that 90 + 10% are captured at the first stage.  Testing with blood samples containing CTC’s verify the effectiveness of the device over a range of operating conditions to develop protocols for future application.  The cell trap requires no power, fits within a point-of-care kit and has now been found to meet functional requirements for incorporation into a point-of-care circulating tumor cell analysis system.