Resonance-Based Sensing of Magnetic Nanoparticles Using Microfluidic Devices with Ferromagnetic Antidot...

Area of Science:

• Nanotechnology
• Applied Physics
• Biomedical Engineering

Background:

• Conventional magnetoresistive detectors face limitations in magnetic nanoparticle detection.
• Planar microresonators offer a promising alternative for on-chip sensing applications.

Purpose of the Study:

• To demonstrate resonance-based detection of magnetic nanoparticles using novel planar microresonator designs.
• To compare indirect detection with ferromagnetic antidot nanostructures and direct detection of nanoparticles.

Main Methods:

• Fabrication of planar microresonators using 3D printed molds for PDMS microfluidic channels.
• Detection of 130 nm magnetic nanoparticle clusters immobilized on sensor surfaces.
• Investigation of two schemes: indirect detection via antidot nanostructures and direct nanoparticle detection.

Main Results:

• Indirect detection using microfluidics showed a resonance field downshift of up to 207 G, significantly higher than droplet introduction (44 G).
• Direct detection without antidot arrays revealed a strong intrinsic nanoparticle resonance.
• Direct detection demonstrated higher sensitivity and simplicity compared to indirect methods.

Conclusions:

• Planar microresonators with ferromagnetic antidot nanostructures can effectively detect magnetic nanoparticles from dispersions.
• Direct resonance detection of magnetic nanoparticles is a simpler and more sensitive approach than indirect methods.