Magnetophoretic trajectory tracking magnetometry: A new technique for assessing magnetic properties of submagnetic microparticles and cells

Abstract

We develop a new approach for assessing magnetic properties of submagnetic microparticles and cells, magnetophoretic trajectory tracking magnetometry (MTTM), that employs recording of long 2D trajectories of particle motion in a slot fluid channel caused by the action of crossed gravitational and magnetic forces. The studies are focused on the development of theoretical backgrounds of the method and evaluation of its uncertainty caused by the mutual hydrodynamic entrainment of moving particles. Computerized equipment implementing MTTM technique is described and its performance is illustrated. According to our studies, the new technique can serve a reliable experimental method with analytical qualities.

Hydrodynamic instability in a magnetically driven suspension of paramagnetic red blood cells

“…7 The suspension sample is confined in a vertical rectangular channel slot with its depth (0.12 mm) much smaller than the width (W = 0.96 mm), and the width much smaller than the height (20 mm). Our experimental setup is a slightly modified magnetophoretic trajectory-tracking magnetometer, recently developed for accessing the magnetic properties of submagnetic microparticles and cells.…”

“…Our experimental setup is a slightly modified magnetophoretic trajectory-tracking magnetometer, recently developed for accessing the magnetic properties of submagnetic microparticles and cells. 7), with its outlet being sealed prior to setting the whole suspension as motionless. The motion proceeds under the action of the mutually perpendicular (in the channel plane) gravity and magnetic force fields.…”

“…Our experimental setup is a slightly modified magnetophoretic trajectory-tracking magnetometer, recently developed for accessing the magnetic properties of submagnetic microparticles and cells. 7 The suspension sample is confined in a vertical rectangular channel slot with its depth (0.12 mm) much smaller than the width (W = 0.96 mm), and the width much smaller than the height (20 mm). The motion proceeds under the action of the mutually perpendicular (in the channel plane) gravity and magnetic force fields.…”

“…1a). The rod diameter (1 mm) is small against the channel height and large against the channel depth, so that the driving magnetic force, except for the border regions near the rod ends, is directed horizontally in the channel plane, is uniform along both the height and depth, and has a simple analytical representation, 7 which makes this model suitable for experimental and theoretical studies. The observation can be done both inside and outside the magnetic field.…”

“…The sample is delivered into the channel by a microhydraulic system (see ref. 7), with its outlet being sealed prior to setting the whole suspension as motionless. Experiments are performed with suspensions prepared by diluting fresh fingertip blood of one of the authors with pharmaceutical saline solution (+2% of serum albumin), followed by 40 min exposure to steady flow on nitrogen of each sample in a sealed, slightly rocking penicillin bottle.…”