Probe type micro magnetic manipulator utilising localised magnetic field with closed-loop magnetic path

Abstract

This paper describes a novel manipulation technique of a single micrometer-scale magnetic particle using a localised magnetic field. An electromagnetic probe consisting of a glass nanopipette was fabricated by coating with ferromagnetic materials inside and outside the nanopipette. The probe edge coated with the magnetic materials was used as the magnetic poles in order to generate a magnetic field with closed-loop magnetic path around the aperture at the edge of the nanopipette. By using the localised magnetic field at the probe edge, a single magnetic particle with 1 mm in diameter could be selectively trapped in liquid condition, and then the trapped individual particles were arranged on a substrate at interval distance of 2 mm. This technique of micromanipulation would be applicable to various fields such as assembling of micro and nanometre-scale devices and measurement for characteristics of biological samples.