Magnetic sensor based on image processing for dynamically tracking magnetic moment of single magnetic mesenchymal stem cell

Abstract Developing an economical and universal method to measure the magnetic moments of magnetic mesenchymal stem cells (MSCs) labelled with superparamagnetic iron oxide (SPIO) nanoparticles is crucial for cell tracking. In this study, we used a gradient magnetic field created by a nickel needle to track the motion of cells. A simple and quantifiable magnetic sensor was employed to evaluate the magnetic properties of single viable MSCs. We measured the magnetic moments of microbeads and MSCs using the proposed method and compared the results with magnetic moments measured using a superconducting quantum interference device and with iron contents measured using an inductively coupled plasma spectrometer, respectively. The correlation coefficients indicated satisfactory agreement in both cases, thus confirming the accuracy of the system. By labelling MSCs with SPIOs, we implemented a miniature magnetic sensor to measure the magnetic moments of single magnetic MSCs quantitatively using an image-processing algorithm. Existing methods for the measurement of magnetic moments at the micro/nanoscale have various limitations. Our system realised the measurement of single viable cells, thereby providing a theoretical foundation for the labelling and tracking of MSCs with SPIO nanoparticles. Additionally, the proposed system is both economical and universal.