Magnetic nanoparticles are promising for many developing biomedical applications, including improved magnetic contrast imaging, hyperthermic treatment of cancer, cancer/disease detection through magnetic relaxometry, and magnetically guided drug delivery. However, the effect of the nanoparticle’s internal morphology (magnetic domains), choice of surface coatings, and collective magnetic interactions on the resulting magnetic response is largely unknown, yet can have significant repercussions on efficacy. Moreover, the possibility of agglomeration from electrochemical attraction or dipolar coupling between magnetic nanoparticles, the process of physical injection into a body (shear flow), and application of static and/or oscillating magnetic fields can profoundly impact performance and safety.
This project will heavily focus on using small-angle neutron scattering (SANS), with the possible addition of neutron spin analysis in order to unambiguously separate the structural and magnetic morphology of magnetic nanoparticles. Transition metal oxides (Fe3O4, MnFe2O4, CoFe2O4, and Co3O4) are commonly studied in this context, but many compositions of magnetic nanoparticles could be suitable. Nanoparticles can be studied in solvated or dried forms. Currently available sample environments include a 7 T superconducting magnet, a 1.6 T electromagnet, a 10 Hz to 20 kHz AC magnet (for timescales of 150 milliseconds to 38 microseconds) with 0.1 T amplitude , sample temperatures ranging from 5 K to 600 K, and a variety of shear-flow cells. Interest and opportunity exist for further decreasing the minimum timescales being probed. The time-dependent magnetic response from both the internal magnetic morphology of individual magnetic nanoparticles and the collective response from an ensemble of nanoparticles would be ideally suited for investigation by SANS.
 C. Glinka et al., J. Appl. Cryst. 53, 598-604 (2020)
Magnetic nanoparticles; Neutron scattering; Polarization (spin alignment); Transition metals; Transition-metal oxides; Hyperthermia, Magnetic Morphology; Agglomeration; Nanoparticle chaining