Two dimensional, electronic particle tracking in liquids with a   graphene-based magnetic sensor array
  The investigation of liquid flow at the nanoscale is a key area of applied research with high relevance to Physics, Chemistry and Biology. We introduce a method and a device that allows to spatially resolve liquid flow by integrating an array of graphene-based magnetic sensors used for tracking the movement of magnetic nanoparticles in the liquid under investigation. With a novel device conception based on standard integration processes and experimentally verified material parameters, we simulate the performance of a single sensor pixel, as well as the whole array, for tracking magnetic nanoparticles. The results demonstrate the ability (a) to detect individual nanoparticles in the liquid and (b) to reconstruct particle trajectories across the sensor array as a function of time, in what we call "Magnetic Nanoparticle Velocimetry" technique. Being a non-optical detection method, potential applications include particle tracking and flow analysis in opaque media at sub-micron scales. 
R. F. Neumann, M. Engel, M. Steiner
cond-mat.mes-hall physics.comp-ph physics.flu-dyn physics.ins-det