Our research focuses on phenomena and applications of dispersions of magnetic nanoparticles subjected to oscillating and rotating magnetic fields. The particles may be dispersed in fluid or solid matrices. When dispersed in Newtonian fluids they are commonly referred to as ferrofluids, which have been studied since the 1960's. In that case their suspension behavior in time varying magnetic fields is of interest as asymmetric states of stress prevail, which is a fundamental departure from the behavior of "ordinary" fluids. Dispersions of magnetic nanoparticles in fluid or solid media find applications in the fields of sensing, separations, cancer treatment, and in anti-counterfeiting, to name a few. We have various ongoing, externally funded projects addressing the fundamental and applied issues. Below are short descriptions of those projects with long-term funding. In addition to these we have various short-term projects or projects under development. |
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Response of Magnetic Nanoparticle Suspensions to Oscillating and Rotating Magnetic Fields This project deals with measurements of torque and velocity profiles in suspensions of magnetic nanoparticles (e.g., magnetite and cobalt ferrite) in Newtonian fluids, polymer solutions, and liquid crystals. Suspensions of magnetic nanoparticles are novel magnetically-active complex fluids, which exhibit magnetic field dependent viscosities and various types of striking instabilities. In the past we have measured magnetic field induced torques using custom magnetorheometers, modeled suspension response, and studied DC field instabilities. Ongoing research focuses on the response of suspensions of spherical and ellipsoidal nanoparticles in Newtonian, non-Newtonian, and liquid crystalline matrices subjected to oscillating magnetic fields. A combined experimental, modeling, and simulation approach is being followed and the results of the research will address key issues in development of magnetic nanoparticle based sensors and therapies. |
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Magnetically and Thermally Active Nanoparticles for Cancer Treatment (In collaboration with Madeline Torres-Lugo, Gustavo Gutierrez, J. Zach Hilt, and Silvina Tomassone). In vitro and in vivo experiments in which cells are in contact with magnetic nanoparticles and subjected to high frequency oscillating magnetic fields have shown that the particles may induce cell death. Owing to the intrinsic biocompatibility of superparamagnetic iron oxide nanoparticles, these observations have garnered considerable interest for the treatment of cancer, in which the nanoparticles could be directly injected into a cancer tumor or functionalized to selectively target cancer cells. The subsequent application of an oscillating magnetic field would result in destruction of the cancer, without many of the deleterious side effect common to radio- and chemotherapy. These observations have been termed Magnetic Fluid Hyperthermia (MFH) or Magnetocytolysis, depending on whether a macroscopic temperature rise is observed. With the objective of improving our fundamental understanding of this phenomenon, this research combines preparation of innovative magnetically and thermally active nanoparticles, experiments aimed at quantifying cell death and the physicochemical interaction between the nanoparticles and human cancer cells in vitro under controlled conditions, modeling and measurements of particle and energy transport in human cancer cells in vitro, and simulations of the interaction between polymers used to functionalize the particles and a model lipid bilayer. |
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Magnetic Nanoparticles for Drug Delivery (in collaboration with Madeline Torres and Eduardo Juan). This project aims to develop heterogeneous multifunctional nanoparticles with a magnetic core and a thermoresponsive block copolymer coating, suitable for the magnetically actuated delivery of drugs. |
