John B. Weaver1, Adam M. Rauwerdink2
1Radiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States; 2Thayer School of Engineering, Dartmouth College, Hanover, NH, United States
The microscopic stiffness of cellular cytoskeleton and the extracellular matrix have been very important in understanding metastasis and angiogenesis but no methods capable of in vivo measurement exist. We show that a new method related to magnetic particle imaging (MPI) called magnetic spectroscopy of nanoparticle Brownian motion (MSB) is sensitive to the stiffness of the microscopic environment surrounding the binding sites of the streptavidin functionalized nanoparticles. The matrix consisted of gels made with mixtures of gelatin and biotinated BSA. Gel stiffness was changed by varying the concentration of gelatin. MSB showed significant differences between each of the gels.