Miniaturized Pulsed Magnetic Field Generator for Biomedical Applications

This paper presents a new miniaturized pulsed magnetic field generator for biomedical applications. The generator is based on the principle of parallel resonance to realize the multiplication of the pulse current in the coil compared to the switching current. This multiplication effect can increase the output capacity of the system while reducing the requirement of switching performance, which is conducive to the miniaturization of the generator design. We built simulation and physical platforms and conducted output tests to verify the feasibility of the topology. Multiplication of the peak coil current by about 1.5 times compared to the peak switch current was achieved in the physical platform, and the peak coil current was made to exceed the through-current limit of the switch. To further explore the conditions under which magnetic perforation occurs, in vitro cellular magnetic perforation experiments were carried out based on the platform constructed to output a pulsed magnetic field with a peak value of 550 mT and a frequency of 1 Hz. By exposing A549 cells to this pulsed magnetic field for a sustained period of 30 min and comparing them with other control groups, it was found that the magnetic field combined with the cisplatin drug resulted in the highest inhibition rate of 65%, which was higher than that of the group administered the drug alone (40%) and the sum of the inhibition rates in the magnetic field alone group (no significant difference), indicating a synergistic effect of the magnetic field with the drug. This work inspired the innovative design of a pulsed magnetic field generator for magnetic perforation and the study of the mechanism of electromagnetic field biological effects.