Novel application of Joule heating to maintain biocompatible temperatures in a fully integrated electromagnetic cell sorting system

Manipulation of magnetically labeled cells in a microfluidic channel is becoming a very important technique in the field of biomedical science. A microfabricated electromagnet produces a large magnetic field gradient in a cell sorting system. The microfabricated electromagnet generates Joule heating so it causes unnecessary heat-up in the device, which has been problematic for the development of a Lab-On-a-Chip (LOC). In this paper, we present a new application of Joule heating to supply thermal energy to an active area of a microfluidic device to increase the internal temperature of the device from ambient to a biocompatible temperature, e.g. 37 °C. The temperature is maintained in conjunction with coolant. We analyzed the temperature distribution of the device numerically and the results were in good agreement with the experimental data. Our approach will facilitate development of cell chips such as a micro-mammalian cell culture or electromagnetic micro-cell sorter.