Novel Biomagnetic Sensing Technique for Characterization of Inflammatory Tissues

We have developed a novel biomagnetic sensing technique, based on the superconducting quantum interference device platform, for detecting the minute magnetic field perturbations associated with biocompatible nanoparticles. This technique has the potential for detecting the presence of small amounts of magnetically labeled cells associated with inflammatory processes. We demonstrated that spatially resolved magnetic images of dry agglomerates of superparamagnetic iron-oxide particles can be obtained at relatively large sample-to-sensor distances. We estimated that the signal-to-noise ratio (SNR) constrained detection limit at the distance of 9 mm is 5nmol (280 ng) iron. We also demonstrated that time-varying magnetic traces of nanoparticle-colloid samples passing the sensor in a laminar flow can be measured at similar sample-to-sensor distances. These experiments showed that the SNR constrained detection limit at the distance of 10 mm is 12.5 nmol (700 ng) iron.