A portable electromagnetic induction heating device for point-of-care diagnostics

Abstract

This paper introduces a portable magnetic field generator for producing wireless induction heating, which has recently been introduced as one of the major thermal techniques in the point-of-care (POC) diagnostic method. To produce induction heating of thin metal structures in a microcentrifuge tube at any time and place, a portable magnetic field generating device was designed and fabricated using the fullbridge FET drive circuit based on a metal-oxide-semiconductor field-effect transistor (MOSFET) and pulse width modulation (PWM). A frequency of 312 kHz was set for effectively heating the micro-scale element, and a high-frequency magnetic field was produced by using a low-power device based on the full-bridge series resonance. Induction heating of two types of heating elements in a microcentrifuge tube was conducted using the new device, and thermal characteristics of induction heating were observed. The device induced eddy currents in both twisted and straight copper elements in the microtube; heating rates were approximately 6.5 J/sec and 3.8 J/sec, respectively. Output voltage of 160 W and magnetic intensity of 80.3 μT were generated by the working coil. This portable magnetic field generator weighs 450 g without a battery and consumes 3600 mAh of power. 70% of Salmonella cells in a concentration of 107 cells/mL was lysed for 15 sec of induction heating with a portable device. The authors conclude that a portable, low-power magnetic field generator can effectively induce heat in a micro-scale heating element, which provides simple and rapid thermal treatment at any time and place.