Analytical magnetapheresis is a technique for analyzing magnetic particles in suspension. The magnetically susceptible particles form a deposition pattern from the suspending medium under carefully controlled flow and magnetic field conditions. This technique was used to determine the effective magnetic volumetric susceptibility, Δχ of human lymphocytes labeled with an iron-rich protein, ferritin. Dynabeads M450, monodisperse polymeric beads doped with magnetite, of a diameter 4.5 μm, close to that of human lymphocytes, were used as a reference. The experiment showed an almost complete deposition of ferritin-labeled lymphocytes at an average flow velocity of 0.28 mm/s, a representative magnetic field of 1.67 T, and a magnetic field gradient of 2.57 T/mm. The calculated Δχ was (2.92 ± 0.24) × 10-6[SI] (ferritin-labeled lymphocytes), and the corresponding number of ferritin molecules per lymphocyte was (1.75 ± 0.44) × 107. In comparison, an almost complete deposition of the Dynabeads was observed at a much higher average flow velocity, 15 mm/s, a much lower field, 0.164 T, and a much lower field gradient, 0.025 T/mm. These results corresponded to a much higher Δχ = 0.245[SI] (Dynabeads M450). These results offer important guidelines in evaluating the use of ferritin as a soluble magnetic cell label.
|Original language||English (US)|
|Number of pages||11|
|State||Published - Oct 15 1995|
ASJC Scopus subject areas
- Analytical Chemistry