(278a) Magnetic Particle and Labeled Cell Characterization – Magnetophoretic Mobility and Particle Size

Magnetic property characterization is of utmost importance prior to utilization of labeled cells and magnetic particles in medical applications and biotechnology.  A particle tracking velocimeter is employed to directly measure the magnetophoretic mobility, size and other morphology parameters of magnetic particles and labeled cells.  The instrument can record and display data derived from up to 30,000 particles or cells in under 10 minutes.    The trajectories of magnetic particles in a uniform isodynamic magnetic field are recorded using a high-definition camera/microscope system for image collection.  Image analysis software then converts the image data to the parameters of interest.  The distribution of magnetophoretic mobility is determined by combining fast image analysis with velocimetry measurements. In addition, multiparametric analysis software displaying 23 parameters per event provides magnetic particle or cell quality information by calculating the size distribution, overall susceptibility, effective magnetic volume, etc. and displaying parameters in multiple dimensions.   Comparison between this method and fluorescence flow cytometry confirms the instrument’s characterization of magnetic particles and labeled cells.  Multiparameter data on cells provides necessary information for the design of a magnetic cell sorter and a point-of-care rare cell detector based on magnetophoretic mobility.

Key Words:  magnetic particles, particle size distribution, magnetophoretic mobility, cell analysis