sing magnetic nanoparticles to absorb alternating magnetic field energy as a method of generating localized hyperthermia
has been shown to be a potential cancer treatment. We are developing delivery systems that use tumor homing cells to
actively carry iron/iron oxide nanoparticles into tumor tissue. We have developed strategies to change the ligand spheres of
superparamagnetic iron/iron oxide nanoparticles to facilitate their rapid uptake by cells capable of ameboid movement. This
approach comprises the synthesis of nanoparticles in microemulsions, the exchange of the nanoparticles? organic ligands
after synthesis, and the formation of double-layers around an iron/iron oxide core (ferrosomes). In addition to making the
nanoparticles sufficiently water soluble, we have been exploring uptake-enhancing peptide sequences, as well as the attachment
of small molecules. To date, we have been testing tumor-tropic neural progenitor cells, endothelial precursor cells, monocyte/
macrophage-like cells and neutrophils.
We have used murine models of disseminated peritoneal pancreatic cancer, metastatic melanoma, and metastatic breast cancer.
After tumor development, the transport cells loaded with iron/iron oxide nanoparticles were injected either intraperitoneally or
intravenously and then allowed to migrate into the tumor. The mice were then exposed to an alternating magnetic field for
20 minutes to cause the cell-delivered nanoparticles to generate heat. We could demonstrate that cell-mediated A/C-magnetic
hyperthermia is a viable alternative to intratumoral injection or intravenous injection of nanoparticles. The advantage of cell-
delivered methods is that the total amount of nanoparticle required is distinctly lower. Depending on the nature of the delivery
cells, different sites within the tumor can be targeted
Stephen Waldman is an Associate Professor and Canada Research Chair at Queen?s University. He has been jointly appointed between the
departments of Chemical Engineering and Mechanical & Materials Engineering since 2003. His research program is centered on the development
of functional orthopaedic tissues (cartilage, ligament and IVD) with specific focus on the effects of biochemical and biomechanical stimuli. He has
published over 60 journal articles, serves on the editorial boards of three biomedical engineering journals, and has served on several grant panel
review committees of the Canadian Institutes of Health Research in the areas of regenerative medicine and biomedical engineering.
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