Migration Analysis of Micro-Particles in Liquids Using Microscopically Designed External Fields

Abstract

The recent development of new migration methods of micro-particles in liquids using various external fields is reviewed. The combination of a laser scattering force and a photothermal effect produced photothermal-conversion laserphotophoresis. A dielectric field generated in a planer or a capillary quadrupole electrode realized dielectrophoresis. Using a micrometer-scaled magnetic field gradient, the "Magnetophoretic velocimetry" of micro-particles was invented. Furthermore, the Lorentz force generated by combining an electric field and a magnetic field was utilized for electromagnetophoresis. These new methods were overlooked and the advantages in analytical use were discussed.

<i>In Situ</i> Microscope Measurements and Analysis of the Passing of Individual Paramagnetic Particles through the Interfaces of Aqueous Two-Phase Systems by Magnetic Force

“…(1) comes from the pressure difference between the interface at the particle and the original interface [9]. The compositions of the upper and lower phases of the ATPS 2 and 4 were reported The downward F m is expressed as [1]:…”

“…For example, a gravitational, a centrifugal, or an electrostatic force is commonly used. Recently, other external forces have been investigated [1].…”

“…However, real-time observation of the particles is difficult to do in a centrifuge. Other forces are effective on particles in solvents, that is, electrostatic, dielectric, electromagnetic, and magnetic forces [1].…”

Charge Simulation Method Calculation of the Inhomogeneous Electric Field near the Dodecane/Water Interface Generated by Two Needle Electrodes

“…Other external fields have also been investigated for their migration [3,4]. For example, dielectrophoresis is the migration of micrometer-sized substances in an inhomogeneous electric field [3,4], and substances of a higher dielectric constant migrate to the stronger electric field region. In any migration, the strength and direction of the external field is essential to the analysis of the migration.…”

Magnetophoretic Evaluation of Interfacial Adsorption of Dysprosium(III) on a Single Microdroplet

“…This is the reason why a lot of techniques to investigate a single microparticle have been developed. [2][3][4][5][6][7] The migration analyses 8 can satisfy this requirement, since the microparticle can be caused to migrate by an extremely weak driving force. For example, only 10 -14 N is enough to move a particle of 1 μm radius at the velocity of 1 μm s -1 , which can be observed by a conventional optical microscope.…”