A DMagnetic Force Manipulator DC Prototype

A potentially useful instrument for the biological sciences would be a dimensional force microscope DFM for measurement of di mensional viscous and elastic elds at sub micrometer scale in vitro and in vivo Substantial development has been conducted on various as pects of this problem but a general instrument having this capability does not yet exist All approaches I know of utilize a microscopic bead as a mechanical probe the position of which can be sensed and the force on which can be controlled One force technique is optical tweez ers This technique requires high optical eld intensities which interact strongly with many materials and may produce undesired side e ects on in vivo experiments Alternatively magnetic techniques use a mag netic bead driven by low frequency magnetic elds which only interact weakly with most biological materials Related prior work includes high gradient techniques Haber a close proximity single pole rheometer Bausch and a two dimensional manipulator Amblard To my knowledge our work is the rst attempt to implement a full three dimen sional magnetic manipulator A low frequency DC prototype magnetic circuit and drive electronics have been designed and built to explore the capabilities of the magnetic technique for a DFM This report com prises a brief description of the DC prototype and a complete set of its design documents This is a report of work in progress and does not present any results of experiments performed on the prototype