Imaging of Magnetic Nanoparticles using Magnetoelectric Sensors

Imaging of magnetic nanoparticles offers a variety of promising medical applications for therapeutics and diagnostics. Using magnetic nanoparticles as tracer material for imaging allows for the non-invasive detection of spatial distributions of nanoparticles that can give information about diseases or can be used in preventive medicine. Imaging biodistributions of magnetically labeled cells offers applicability for tissue engineering, as a means to monitor cell growth within artificial scaffolds non-destructively. In the presented work, the capabilities of an imaging system for magnetic nanoparticles via magnetoelectric sensors are investigated. The investigated technique, called Magnetic Particle Mapping, is based on the detection of the nonlinear magnetic response of magnetic nanoparticles. A resonant magnetoelectric sensor is used for frequency selective measurements of the nanoparticles magnetic response. Extensive modeling was performed that enabled proper imaging of magnetic nanoparticle distributions. Fundamental limitations of the imaging system were derived to describe resolution in correspondence to signal-to-noise ratios. Incorporation of additional parameters in the imaging system for the data analysis resulted in an algorithm for a more robust reconstruction of spatial particle distributions, increasing its imaging capabilities. Experimental investigations of the imaging system show the capabilities for imaging of cell densities using magnetically labeled cells. Furthermore, resolution limitations were investigated and differentiation of different particle types in imaging was shown, referred to as ”colored” imaging. The imaging of biodistributions of magnetically labeled cells thus enable exciting perspectives on further research and possible applications in tissue engineering.