Shaped Magnetogel Microparticles for Multispectral Magnetic Resonance Contrast and Sensing

Published

December 19, 2023

Author(s)

Samuel Oberdick, Stephen Dodd, Alan Koretsky, Gary Zabow

Abstract

A promising form of magnetic resonance imaging (MRI) contrast, known as multispectral or "color" contrast, encodes protons with discrete frequencies (i.e., colors) using micro-engineered control of magnetic fields. Manipulation of local magnetic fields is accomplished using microfabricated three-dimensional contrast agents. The contrast agents have a unique radiofrequency (RF) resonance that can be controlled by tuning geometric parameters of the structure. Further, the multispectral contrast of these agents can be engineered to respond to environmental conditions, providing a pathway for remote sensing. These geometrically encoded magnetic sensors (GEMS) have a shape-changing response to environmental conditions, which allows for magnetic resonance-based sensing via change in the RF resonance. Previously, GEMS have been made using procedures adapted from thin film lithography in a cleanroom environment. While these techniques offer precise geometric control of the microstructure, they can be a limitation for researchers who do not have access to a cleanroom facility or microfabrication expertise. Here, an alternative approach for GEMS fabrication based on soft lithography is introduced. The fabrication scheme uses cheap, accessible materials and simple chemistry to produce shaped magnetic hydrogel microparticles with multispectral MRI contrast properties. The microparticles can be used as sensors by fabricating them out of shape-reconfigurable, "smart" hydrogels. The change in shape causes a corresponding shift in the resonance of the GEMS, producing an MRI-addressable readout of the microenvironment. Proof-of-principle experiments showing multispectral response to pH change with cylindrical shell magnetogel GEMS are presented.

Citation

Small

Pub Type

Journals

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Keywords

Magnetic resonance imaging, microparticles, magnetic materials, sensors

Citation

Oberdick, S. , Dodd, S. , koretsky, A. and Zabow, G. (2023), Shaped Magnetogel Microparticles for Multispectral Magnetic Resonance Contrast and Sensing, Small, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936825 (Accessed December 26, 2024)