Thales: an instrument to measure the low field magnetophoretic mobility of microscopic objects

An instrument, Thales, was designed and constructed to measure the inducedmotion of magnetic microspheres in a low magnetic field strength environment. Results showthat Thales can be used to precisely measure the speed of microspheres (± 0.08 μm.s-1). Weevaluated the motion of magnetic microspheres induced by an inhomogeneous magnetic field,and developed models for the microsphere magnetophoretic mobility, a parameter determiningthe speed attained by the microsphere in a given static low strength magnetic fieldenvironment. The data suggested that the magnetic material was located at the surfaces of themicrospheres rather than being distributed evenly through the microspheres. With suitablecalibration microspheres, Thales will be capable of directly measuring the low fieldmagnetophoretic mobility of microscopic objects.