  Magnetic particle spectroscopy (MPS), also called magnetization response
spectroscopy, is a novel measurement tool derived from magnetic particle
imaging (MPI). It can be interpreted as a zero-dimensional version of MPI
scanner. MPS was primarily designed for characterizing superparamagnetic iron
oxide nanoparticles (SPIONs) regarding their applicability for MPI. In recent
years, it has evolved into an independent, versatile, highly sensitive,
inexpensive platform for biological and biomedical assays, cell labeling and
tracking, and blood analysis. MPS has also developed into an auxiliary tool for
magnetic imaging and hyperthermia by providing high spatial and temporal
mappings of temperature and viscosity. Furthermore, other MPS-based
applications are being explored such as magnetic fingerprints for product
tracking and identification in supply chains. There are a variety of novel
MPS-based applications being reported and demonstrated by many groups. In this
short review, we highlighted some of the representative applications based on
MPS platform, thereby providing a roadmap of this technology and our insights
for researchers in this area.
