Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot Nanostructures

The capture of magnetic nanoparticles (MNPs) is essential in the separation and detection of MNPs for applications such as magnetic biosensing. The sensitivity of magnetic biosensors inherently depends upon the distribution of captured MNPs within the sensing area. We previously demonstrated that th...

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Main Authors: Reyne Dowling, Mikhail Kostylev
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/2/132
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author Reyne Dowling
Mikhail Kostylev
author_facet Reyne Dowling
Mikhail Kostylev
author_sort Reyne Dowling
collection DOAJ
description The capture of magnetic nanoparticles (MNPs) is essential in the separation and detection of MNPs for applications such as magnetic biosensing. The sensitivity of magnetic biosensors inherently depends upon the distribution of captured MNPs within the sensing area. We previously demonstrated that the distribution of MNPs captured from evaporating droplets by ferromagnetic antidot nanostructures can be controlled via an external magnetic field. In this paper, we demonstrate the capture of magnetic nanoparticles from a microfluidic flow by four variants of antidot array nanostructures etched into 30 nm thick Permalloy films. The nanostructures were exposed to 130 nm MNP clusters passing through microfluidic channels with square cross-sections of 400 μm × 400 μm. In the presence of a parallel magnetic field, up to 83.1% of nanoparticles were captured inside the antidot holes. Significantly higher proportions of nanoparticles were captured within the antidots from the flow than when applying the nanoparticles via droplets. In the parallel field configuration, MNPs can be focused into the regularly spaced antidot indents in the nanostructure, which may be useful when detecting or observing MNPs and their conjugates. Conversely, up to 84% of MNPs were caught outside of antidots under a perpendicular magnetic field. Antidot nanostructures under this perpendicular configuration show potential for MNP filtration applications.
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spelling doaj-art-dca28fb46c5648b9ac2f36438e1c086e2025-01-24T13:44:15ZengMDPI AGNanomaterials2079-49912025-01-0115213210.3390/nano15020132Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot NanostructuresReyne Dowling0Mikhail Kostylev1Department of Physics, The University of Western Australia, Perth, WA 6009, AustraliaDepartment of Physics, The University of Western Australia, Perth, WA 6009, AustraliaThe capture of magnetic nanoparticles (MNPs) is essential in the separation and detection of MNPs for applications such as magnetic biosensing. The sensitivity of magnetic biosensors inherently depends upon the distribution of captured MNPs within the sensing area. We previously demonstrated that the distribution of MNPs captured from evaporating droplets by ferromagnetic antidot nanostructures can be controlled via an external magnetic field. In this paper, we demonstrate the capture of magnetic nanoparticles from a microfluidic flow by four variants of antidot array nanostructures etched into 30 nm thick Permalloy films. The nanostructures were exposed to 130 nm MNP clusters passing through microfluidic channels with square cross-sections of 400 μm × 400 μm. In the presence of a parallel magnetic field, up to 83.1% of nanoparticles were captured inside the antidot holes. Significantly higher proportions of nanoparticles were captured within the antidots from the flow than when applying the nanoparticles via droplets. In the parallel field configuration, MNPs can be focused into the regularly spaced antidot indents in the nanostructure, which may be useful when detecting or observing MNPs and their conjugates. Conversely, up to 84% of MNPs were caught outside of antidots under a perpendicular magnetic field. Antidot nanostructures under this perpendicular configuration show potential for MNP filtration applications.https://www.mdpi.com/2079-4991/15/2/132ferromagnetic materialsmicrofluidicssoft lithographysuperparamagnetic iron oxide nanoparticlesmagnetic nanoparticlesmagnetophoresis
spellingShingle Reyne Dowling
Mikhail Kostylev
Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot Nanostructures
Nanomaterials
ferromagnetic materials
microfluidics
soft lithography
superparamagnetic iron oxide nanoparticles
magnetic nanoparticles
magnetophoresis
title Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot Nanostructures
title_full Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot Nanostructures
title_fullStr Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot Nanostructures
title_full_unstemmed Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot Nanostructures
title_short Controlled Capture of Magnetic Nanoparticles from Microfluidic Flows by Ferromagnetic Antidot and Dot Nanostructures
title_sort controlled capture of magnetic nanoparticles from microfluidic flows by ferromagnetic antidot and dot nanostructures
topic ferromagnetic materials
microfluidics
soft lithography
superparamagnetic iron oxide nanoparticles
magnetic nanoparticles
magnetophoresis
url https://www.mdpi.com/2079-4991/15/2/132
work_keys_str_mv AT reynedowling controlledcaptureofmagneticnanoparticlesfrommicrofluidicflowsbyferromagneticantidotanddotnanostructures
AT mikhailkostylev controlledcaptureofmagneticnanoparticlesfrommicrofluidicflowsbyferromagneticantidotanddotnanostructures