Towards ferro-microfluidics for effective and rapid cellular manipulation and sorting

We present a rapid and completely label-free cellular manipulation and separation scheme that employs biocompatible, water-based ferrofluids within microfluidic devices. Application of localized magnetic fields through integrated electrodes exerts strong magnetic forces on any micro- particle that forms a magnetic void within the ferrofluid medium in a channel. The magnetic force on each micro-particle depends sensitively on its size (tens of pN for 2 mum diameter) and is an order of magnitude larger than what can be achieved by traditional methods, such as optical tweezers and dielectrophoresis. As such, cellular manipulation and hundreds of microns of separation can easily be accomplished within ferro- microfluidic devices on a time scale of a few seconds, even under low and moderate current values.