Energetic constraints on the creation of cell membrane pores by magnetic
Vaughan TE, Weaver JC Biophysical Journal 71: (2) 616-622 AUG 1996
Naturally occurring and contaminant ferromagnetic and ferrimagnetic
particles have been found within or near cells, and might allow pulsed
magnetic fields to create transient cell membrane openings (''pores'').
We show that this possibility is significantly constrained by the maximum
rotational energy that can be transferred to the cell membrane. For
single biologically synthesized magnetosomes (radius r(mag) approximate
to 10(-7) m, magnetic moment mu approximate to 2 x 10(-15) A m(2)) and
typical cell membranes, the estimated pulse magnitude must exceed B-0
approximate to 6 x 10(-3) to 7 x 10(-2) T, and the optimal pulse durations
are in the range 10(-5) s < t(pulse) < 10(-1) s. For larger contaminant
particles with larger net magnetic moments, the pulse magnitudes could
be only somewhat smaller, and the optimal durations are about the same.
Very large pulses that exceed the coercive force of a particle are
predicted to have a smaller effective magnitude and shorter effective