Frequency and Amplitude Optimizations for Magnetic Particle Spectroscopy Applications

Abstract

Nowadays, there is a growing interest in the field of magnetic particle spectroscopy (MPS)-based bioassays. MPS monitors the dynamic magnetic response of surface-functionalized magnetic nanoparticles (MNPs) upon excitation by an alternating magnetic field (AMF) to detect various target analytes. This technology has flourished in the past decade due to its low cost, low background magnetic noise interference from the biomatrix, and fast response time. A large number of MPS variants have been reported by different groups around the world, with applications ranging from disease diagnosis to foodborne pathogen detection and virus detection. However, there is an urgent need for guidance on how to optimize the sensitivity of MPS detection by choosing different types of MNPs, AMF modalities, and MPS assay strategies (i.e., volume-and surface-based assays). In this work, we systematically study the effect of AMF frequencies and amplitudes on the responses of single-and multicore MNPs under two extreme conditions, namely, the bound and unbound states. Our results show that some modalities such as dual-frequency MPS utilizing multicore MNPs are more suitable for surface-based bioassay applications, whereas single-frequency MPS systems using single-or multicore MNPs are better suited for volumetric bioassay applications. Furthermore, the bioassay sensitivities for these modalities can be further improved by a careful selection of AMF frequencies and amplitudes.

Static and Dynamic Magnetization Responses of Self-Assembled Magnetic Nanoparticle Chains

“…For studying the MPS spectra, the third harmonic response was captured at 3f (15 kHz), and the fifth harmonic was captured at 5f (25 kHz) harmonic peaks after fast Fourier transform (FFT) implementation. The real-time voltage response of the MNP samples was used for the construction of the dynamic magnetization response (i.e., AC M–H loops) as detailed in our previous work . The system was also allowed to rest for 2 min between multiple data collections to avoid any thermal effects.…”

“…The real-time voltage response of the MNP samples was used for the construction of the dynamic magnetization response (i.e., AC M−H loops) as detailed in our previous work. 43 The system was also allowed to rest for 2 min between multiple data collections to avoid any thermal effects.…”

Nanomaterial-Based Biosensors for SARS-CoV-2 and Future Epidemics

“…MPS works on the principle of measuring the magnetization response of MNPs under the influence of AC excitation fields . Upon the application of an excitation field, MNPs undergo the Néel and Brownian relaxation processes ,, to align their magnetic moments with the applied field direction. This relaxation occurs because of either the physical rotation of the MNP, as in the case of the Brownian relaxation mechanism, or via rotation of magnetic moment inside the crystalline structure of MNP such as in the case of Néel relaxation.…”

A method for multiplexed and volumetric-based magnetic particle spectroscopy bioassay: mathematical study

“…All the simulation work was performed using the 'resolvable' set of MNPs, however under different SNR conditions. SNR can vary due to a variety of reasons [27] such as (1) choice of MPS modality, i.e. single-vs dualfrequency MPS, (2) choice of the operating frequency of the AC driving fields, (3) choice of detection methodology such as lock-in vs non-lock-in based implementation, and/or (4) design of the driving and detection coils in the MPS system.…”