Directional control on a microfluidic chip

A microfluidic system comprising:

• a fluidic platform having a surface;
• a first liquid disposed onto the fluidic platform, the first liquid having a first temperature;
• an array of selectively energizable electrodes, positioned adjacent to an edge of the fluidic platform, configured to provide digital microfluidics to cause movement of a droplet comprising a second liquid containing magnetic nanoparticles from a location over the array of selectively energizable electrodes to a location over the fluidic platform such that the droplet is disposed over the first liquid;
• and
• an array of selectively energizable electromagnets positioned proximate to the fluidic platform and configured to provide an alternating electromagnetic field in a radiofrequency range to heat the magnetic nanoparticles in the droplet thereby causing the droplet to reach a second temperature that is higher than the first temperature such that the droplet is levitated above the first liquid by a cushion of vapor of the first liquid.

A method comprising:

• providing a microfluidic system comprising:
• a fluidic platform having a surface;
• a first liquid disposed onto the fluidic platform, the first liquid having a first temperature;
• an array of selectively energizable electrodes configured to provide digital microfluidics, the array of selectively energizable electrodes positioned adjacent to an edge of the fluidic platform, wherein the array of selectively energizable electrodes is configured to move a droplet comprising a second liquid containing magnetic nanoparticles from a location over the-array of selectively energizable electrodes to a location over the fluidic platform such that the droplet is disposed over the first liquid;
• and
• an array of selectively energizable electromagnets positioned proximate to the fluidic platform and configured to provide:
• an alternating electromagnetic field configured to heat the magnetic nanoparticles in the droplet, thereby causing the droplet to reach a second temperature that is higher than the first temperature such that the droplet is levitated above the first liquid by a cushion of vapor of the first liquid;
• and
• a magnetic field that has variable strength across the surface by selectively energizing different subsets of the electromagnets, thereby causing application of a magnetic force to the magnetic nanoparticles in the droplet to move the droplet on the cushion of vapor of the first liquid
• the method further comprising:
• moving, by selectively energizing a subset of the array of the selectively energizable electrodes, a first droplet comprising a second liquid containing first magnetic nanoparticles from a first location over the array of selectively energizable electrodes to a second location over the fluidic platform such that the first droplet is disposed over the first liquid;
• and
• heating the first droplet to a second temperature that is higher than the first temperature, wherein the heating of the first droplet is carried out by an alternating magnetic field provided through the array of selectively energizable electromagnets, such that the first droplet is levitated above the first liquid by a first cushion of vapor of the first liquid.