Thermally or deterministically-driven transport of objects through asymmetric potential energy landscapes (ratchet-based motion) is of considerable interest as models for biological transport and as methods for controlling the flow of information, material, and energy.  Here, we provide a general framework for implementing the multiplexed separation of magnetic colloids based on size.  Our approach is based on quasi-static (adiabatic) transitions in a tunable potential energy landscape composed of a multi-frequency magnetic field input signal with the static field of a spatially periodic magnetization.  By tuning both the phase shifts between the input signals and the relative forcing coefficients, medium sized particles can transport across the substrate, whereas large or small-sized particles remain trapped in closed orbits (i.e., a bandpass filter).  The reverse situation in which large and small size particles can be transported, whereas medium sized particles are trapped in closed orbits, can also be achieved (i.e., a bandgap filter).

Multiplexed motion of magnetic beads on a magnetic ratchet

245th National Meeting (2013)

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