Convective flows in 3-dimensional microfluidic networks induced by localized microwave heating

We present a natural convection microfluidic loop, based on localized microwave heating of fluids, as a concept for driving flows in 3-dimensional lab-on-a-chip architectures. As a proof of principle we fabricated test devices by using standard power RF-components, originally developed for mobile wireless communication applications, which are combined with Polydimethylsiloxane (PDMS) imprint technology for the realization of fluidic driving unit and channel, respectively. It is demonstrated that microwave fields coupled into the channel by the open end of a miniature coax cable lead to localized dielectric and, to a minor degree, also resistive heating of the fluid which induces a unidirectional, convective flow in the microfluidic network.