Authors: J.K. Park, J.J. Jung, P. Subramaniam, B. Shah, C.J. Kim, J.K. Lee, K.B. Lee
Affilation: Korea Research Institute of Chemical Technology, Korea
Pages: 367 - 370
Keywords: magnetic nanoparticles, MRI, diagnosis, therapy
An effective therapeutic approach against cancer requires the combination of several modalities such as chemotherapy, radiation, and hyperthermia. However, the development of multifunctional nanomaterial-based systems that can provide the combined therapeutics and molecular imaging with high sensitivity and selectivity is limited and not fully explored. Recently, metal alloys magnetic nanoparticles, such as FeCo have been developed for MRI probes due to high magnetization. Thus far, degradation of nanocrystalline FeCo due to oxidation and potential toxicity of Co have prevented utilization of FeCo in biological applications. In order to access the much higher magnetic moments of metal alloys magnetic nanoparticles and more stability, the magnetic core could be protected by an additional surface coating that should be chemically inert towards air and acids, and stable at elevated temperatures. Enclosure of FeCo magnetic nanoparticles in carbon graphite is of particular interest since it could prevent their degradation in reaction chemical environments and isolate the particles magnetically from each other to avoid low proximity interactions. Herein we describe the novel synthesis of graphitic carbon-shell protected iron cobalt magnetic nanoparticles (FeCo/C MNPs) by a hydrothermal synthetic method. The FeCo/C MNPs exhibit high magnetization, excellent magnetic resonance imaging (MRI) contrast both in vitro and in vivo, and highly sensitive hyperthermal effects. We have also demonstrated that the combination of FeCo/C MNP-based siRNA delivery against the oncogenic receptor (EGFRvIII) with hyperthermia using the same MNPs results in a synergistic inhibition of brain-tumor cell proliferation and induction of apoptosis. Our results present the potential of using these nanoparticles for the simultaneous imaging, diagnosis, and cancer therapies. Herein, we describe the novel synthesis of magnetic nanomaterials with a graphitic-shell (FeCo/C) for targeted delivery of multifunctional siRNA-MNP constructs for sensitizing target brain tumor cells (bTCs) to hyperthermia and for the selective knockdown of the epidermal growth factor receptor variant III (EGFRvIII) in bTCs, resulting in the synergistic inhibition of tumor cell proliferation and induction of apoptosis via the deactivation of the PI3K/AKT signaling pathway.