INTEGRATED HIGH MAGNETIC GRADIENT SYSTEM FOR TRAPPING NANOPARTICLES

Abstract

Lab-on-chip (LoC) magnetic separator is important in clinical diagnostics and biological studies where different types of biological cells need to be isolated from its heterogeneous population. In this work, a novel design of on-chip V-shaped magnetic core generating high magnetic gradient and force for trapping magnetically labelled bioparticles is presented. The integrated magnetic system consisted of a spiral-shaped planar microcoils and a V-shaped permalloy (Ni80Fe20) magnetic core structure, which was designed to be part of LoC separator system. The effects of V-shaped magnetic core tip area, the current injection to the microcoils on the magnetic field, as well as its gradient and force on magnetic nanoparticles were simulated and analyzed. Finite element analysis (FEA) simulation using two dimensional (2D) axial symmetry model and steady state analysis of the DC magnetostatics module confirmed the effect of V-shaped magnetic core tip on the high magnetic field generation. The smallest V-shaped magnetic core tip area and the highest current injected to the magnetic coils had significantly amplified the magnetic flux density, its gradient, and the magnetic force generated on a magnetic nanoparticles. Functional test results justified the proportional relationship between DC applied and the trapping area of the magnetic nanoparticles. Effective separation of biological cells tagged with magnetic nanoparticles in LoC system was expected with integration of this high gradient on-chip magnetic system.