Microfluidic chip for susceptibility of superparamagnetic nanoparticles of bead and droplet types and measuring method for susceptibility using the same

A method for measuring the magnetic susceptibility of a superparamagnetic nanoparticle bead comprises the steps of:

• (1) injecting a continuous phase fluid and a magnetic fluid into a continuous phase fluid-moving microfluidic channel and a magnetic fluid-moving microfluidic channel, respectively, in a microfluidic chip;
• (2) allowing the continuous phase fluid and the magnetic fluid, injected in step (1), to meet each other to form a superparamagnetic nanoparticle bead droplet;
• and
• (3) measuring the magnetic susceptibility of a superparamagnetic nanoparticle bead present in the droplet when the superparamagnetic nanoparticle bead droplet formed in step (2) passes over an active junction area of a planar Hall resistive sensor,
• wherein the microfluidic chip comprises a planar Hall resistive sensor comprising an active junction area for sensing the superparamagnetic nanoparticle bead and droplet, which protrudes from an underlying substrate and in which a first arm having current electrodes at both ends and a second arm having voltage electrodes at both ends cross each other, wherein the first arm has a controlled length;
• and microfluidic channels crossing over the active junction area of the planar Hall resistive sensor.