Dongfei Chen ¹ Teresa Zardan Gomez De La Torre ² Fuxiang Wei ³ Bo Tian ^4* Kai Wu ^5*

• ¹ Graduate School of Biomedical Engineering, University of New South Wales, Kensington, New South Wales, Australia
• ² Department of Material Sciences and Engineering, Uppsala University, Uppsala, Uppsala, Sweden
• ³ Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
• ⁴ Department of Biomedical Engineering, Central South University, Changsha, China
• ⁵ Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas, United States

to act as precise and versatile tools within analytical systems, facilitating high sensitivity and selectivity even in complex biological matrices. Importantly, MNPs exhibit strong contrast against biological materials, allowing the detection of trace biomolecules-a key requirement in early-stage diagnostics. As a result, there has been remarkable growth in the application of magnetic particle-assisted sensing and magnetic biosensors over the past decade.Magnetic particle-assisted sensing leverages the ability to apply external magnetic fields (static or dynamic) to MNPs, enabling remote manipulation of the particles in a diverse environment (Glog et al., 2019). Typically, these fields provide precise control over MNP functions such as extraction, stirring, and sorting, while also facilitating specific biophysical measurements via magnetic, optical, or electrochemical signal transduction. Additionally, magnetic forces can enhance particle interactions, overcoming diffusion limits to improve reaction kinetics for fast and uniform assay performance (Xiao et al., 2022). This capability is essential in applications requiring rapid response times, including point-of-care diagnostics and environmental monitoring.Despite these advantages, several challenges persist in the use of MNPs for sensing.For example, magnetic incubation processes can lead to non-specific binding, which increases background signals and subsequently reduces system sensitivity. Achieving multiplex detection-where multiple targets are identified simultaneously-adds further complexities, as distinguishing between signals from various types of magnetic particles remains challenging. Furthermore, current techniques such as magnetic relaxation switching often face difficulties in differentiating signals when multiple particle types are present. Overcoming these limitations is critical to advancing MNPenabled sensing technologies, necessitating innovations in materials fabrication, signal processing, and sensor design to enhance system robustness and versatility (Wu et al., 2019).