The Experts below are selected from a list of 3171 Experts worldwide ranked by ideXlab platform
Takeshi Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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Cancer hyperthermia using magnetic Nanoparticles
Biotechnology Journal, 2011Co-Authors: Takeshi KobayashiAbstract:Magnetic-Nanoparticle-mediated intracellular hyperthermia has the potential to achieve localized tumor heating without any side effects. The technique consists of targeting magnetic Nanoparticles to tumor tissue followed by application of an external alternating magnetic field that induces heat through Neel relaxation loss of the magnetic Nanoparticles. The temperature in tumor tissue is increased to above 43°C, which causes necrosis of cancer cells, but does not damage surrounding normal tissue. Among magnetic Nanoparticles available, Magnetite has been extensively studied. Recent years have seen remarkable advances in Magnetite-Nanoparticle-mediated hyperthermia; both functional Magnetite Nanoparticles and alternating-magnetic-field generators have been developed. In addition to the expected tumor cell death, hyperthermia treatment has also induced unexpected biological responses, such as tumor-specific immune responses as a result of heat-shock protein expression. These results suggest that hyperthermia is able to kill not only local tumors exposed to heat treatment, but also tumors at distant sites, including metastatic cancer cells. Currently, several research centers have begun clinical trials with promising results, suggesting that the time may have come for clinical applications. This review describes recent advances in Magnetite Nanoparticle-mediated hyperthermia.
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anti cancer effect of hyperthermia on breast cancer by Magnetite Nanoparticle loaded anti her2 immunoliposomes
Breast Cancer Research and Treatment, 2009Co-Authors: Toyone Kikumori, Takeshi Kobayashi, Masataka Sawaki, Tsuneo ImaiAbstract:Background We have constructed anti-HER2 immunoliposomes containing Magnetite Nanoparticles (HML) that generate heat in an alternating magnetic field (AMF). The effective targeting and cytocidal abilities of HML have been achieved using cell culture models. This study aimed to investigate feasibility of this modality for breast cancer treatment using tumor-bearing mouse models. Material and methods The subcutaneous cancer nodules of BT474 (high HER2 expression) or SKOV3 (low HER2 expression) cells in nude mice were employed as models. HMLs were injected into these cancer nodules and were then exposed to an AMF for 30 min twice at 24 h intervals. Accumulation of Magnetite and tumor growth rates were examined. Histological findings of the thermal effect were also examined. Results HMLs accumulated in only BT474 tumors. The tumor temperature increased to 45°C whereas the body temperature remained at around 38°C. Tumor regression was observed in the hyperthermic group and was sustained for 10 weeks after hyperthermia. Conclusion These results suggest that hyperthermia using HML is an effective and specific therapy for breast cancer overexpressing HER2. This therapy may provide an alternative way to treat recurrent cancer refractory to other modalities.
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Magnetite Nanoparticle loaded anti her2 immunoliposomes for combination of antibody therapy with hyperthermia
Cancer Letters, 2004Co-Authors: Akira Ito, Yuko Kuga, Hiroyuki Honda, Hiroyuki Kikkawa, Atsushi Horiuchi, Yuji Watanabe, Takeshi KobayashiAbstract:Abstract Anti-HER2 antibody can induce antitumor responses, and can be used in delivering drugs to HER2-overexressing cancer. Previously, we produced hyperthermia using Magnetite Nanoparticles that generate heat in an alternating magnetic field. In the present study, we constructed anti-HER2 immunoliposomes containing Magnetite Nanoparticles, which act as tumor-targeting vehicles, combining anti-HER2 antibody therapy with hyperthermia. The Magnetite Nanoparticle-loaded anti-HER2 immunoliposomes exerted HER2-mediated antiproliferative effects on SKBr3 breast cancer cells in vitro. Moreover, 60% of Magnetite Nanoparticles were incorporated into SKBr3, and the cells were then heated at 42.5 °C under an alternating magnetic field, resulting in strong cytotoxic effects. These results suggest that this novel therapeutic tool is applicable to treatment of HER2-overexpressing cancer.
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Magnetite Nanoparticle loaded anti her2 immunoliposomes for combination of antibody therapy with hyperthermia
Cancer Letters, 2004Co-Authors: Akira Ito, Yuko Kuga, Hiroyuki Honda, Hiroyuki Kikkawa, Atsushi Horiuchi, Yuji Watanabe, Takeshi KobayashiAbstract:Anti-HER2 antibody can induce antitumor responses, and can be used in delivering drugs to HER2-overexpressing cancer. Previously, we produced hyperthermia using Magnetite Nanoparticles that generate heat in an alternating magnetic field. In the present study, we constructed anti-HER2 immunoliposomes containing Magnetite Nanoparticles, which act as tumor-targeting vehicles, combining anti-HER2 antibody therapy with hyperthermia. The Magnetite Nanoparticle-loaded anti-HER2 immunoliposomes exerted HER2-mediated antiproliferative effects on SKBr3 breast cancer cells in vitro. Moreover, 60% of Magnetite Nanoparticles were incorporated into SKBr3, and the cells were then heated at 42.5 degrees C under an alternating magnetic field, resulting in strong cytotoxic effects. These results suggest that this novel therapeutic tool is applicable to treatment of HER2-overexpressing cancer.
Kannan M Krishnan - One of the best experts on this subject based on the ideXlab platform.
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tuning surface coatings of optimized Magnetite Nanoparticle tracers for in vivo magnetic particle imaging
IEEE Transactions on Magnetics, 2015Co-Authors: Amit P Khandhar, Matthew R Ferguson, Hamed Arami, Scott Jeffrey Kemp, Kannan M KrishnanAbstract:Surface coatings are important components of magnetic particle imaging (MPI) tracers—they preserve their key properties responsible for optimum tracer performance in physiological environments. In vivo , surface coatings form a physical barrier between the hydrophobic superparamagnetic iron oxide Nanoparticles (SPION) cores and the physiological environment, and their design dictates the blood half-life and biodistribution of MPI tracers. Here, we show the effect of tuning poly(ethylene glycol) (PEG)-based surface coatings on both in vitro and in vivo (mouse model) MPI performance of SPIONs. Our results showed that varying PEG molecular weight had a profound impact on colloidal stability, characterized using dynamic light scattering, and the m’ ( H ) response of SPIONs, measured in a 25 kHz/20 mT $ \mu _{\text {0}}^{\text {-1}}{}_{ {\rm max}}$ magnetic particle spectrometer. Increasing PEG molecular weight from 5 to 20 kDa preserved colloidal stability and m’ ( H ) response of ${\sim } \text{25}$ nm SPIONs—the optimum core diameter for MPI—in serum-rich cell culture medium for up to 24 h. Furthermore, we compared the in vivo circulation time of SPIONs as a function of hydrodynamic diameter and showed that clustered SPIONs can adversely affect blood half-life; critically, SPIONs with clusters had five times shorter blood half-life than individually coated SPIONs. We anticipate that the development of MPI SPION tracers with long blood half-lives have potential not only in vascular imaging applications, but also enable opportunities in molecular targeting and imaging—a critical step toward early cancer detection using the new MPI modality.
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Drive-Field Frequency Dependent MPI Performance of Single-Core Magnetite Nanoparticle Tracers
IEEE Transactions on Magnetics, 2015Co-Authors: Christian Kuhlmann, Meinhard Schilling, Amit P Khandhar, Kannan M Krishnan, Richard Matthew Ferguson, Scott Kemp, Thilo Wawrzik, Frank LudwigAbstract:The drive-field frequency of magnetic particle imaging (MPI) systems plays an important role for system design, safety requirements, and tracer selection. Because the commonly utilized MPI drive-field frequency of 25 kHz might be increased in future system generations to avoid peripheral nerve stimulation, a performance evaluation of tracers at higher frequencies is desirable. We have studied single-core Magnetite Nanoparticles that were optimized for MPI applications, utilizing magnetic particle spectrometers (MPS) with drive-field frequencies in the range from 1 to 100 kHz. The particles have core diameters of 25 nm and a hydrodynamic size of 77 nm. Measurements in the frequency range above 5 kHz were carried out with a newly designed MPS system. In addition, to exclude possible particle interaction, samples of different concentrations were characterized and compared.
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monodisperse Magnetite Nanoparticle tracers for in vivo magnetic particle imaging
Biomaterials, 2013Co-Authors: Amit P Khandhar, Matthew R Ferguson, Hamed Arami, Kannan M KrishnanAbstract:Magnetic Particle Imaging (MPI) is a new biomedical imaging modality that produces real-time, highresolution tomographic images of superparamagnetic iron oxide (SPIO) Nanoparticle tracer distributions. In this study, we synthesized monodisperse tracers for enhanced MPI performance and investigated both, their blood clearance time using a 25 kHz magnetic particle spectrometer (MPS), and biodistribution using a combination of quantitative T2-weighted MRI and tissue histology. In vitro and in vivo MPI performance of our magnetic Nanoparticle tracers (MNTs), subject to biological constraints, were compared to commercially available SPIOs (Resovist). Monodisperse MNTs showed a 2-fold greater signal per unit mass, and 20% better spatial resolution. In vitro evaluation of tracers showed that MPI performance of our MNTs is preserved in blood, serum-rich cell-culture medium and gel; thus independent of changes in hydrodynamic volume and fluid viscosity e a critical prerequisite for in vivo MPI. In a rodent model, our MNTs circulated for 15 min e 3� longer than Resovist e and supported our in vitro evaluation that MPI signal is preserved in the physiological environment. Furthermore, MRI and histology analysis showed that MNTs distribute in the reticuloendothelial system (RES) in a manner similar to clinically approved SPIO agents. MNTs demonstrating long-circulation times and optimized MPI performance show potential as angiography tracers and blood-pool agents for the emerging MPI imaging modality.
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monodisperse Magnetite Nanoparticle tracers for in vivo magnetic particle imaging
Biomaterials, 2013Co-Authors: Amit P Khandhar, Matthew R Ferguson, Hamed Arami, Kannan M KrishnanAbstract:Abstract Magnetic Particle Imaging (MPI) is a new biomedical imaging modality that produces real-time, high-resolution tomographic images of superparamagnetic iron oxide (SPIO) Nanoparticle tracer distributions. In this study, we synthesized monodisperse tracers for enhanced MPI performance and investigated both, their blood clearance time using a 25 kHz magnetic particle spectrometer (MPS), and biodistribution using a combination of quantitative T2-weighted MRI and tissue histology. In vitro and in vivo MPI performance of our magnetic Nanoparticle tracers (MNTs), subject to biological constraints, were compared to commercially available SPIOs (Resovist). Monodisperse MNTs showed a 2-fold greater signal per unit mass, and 20% better spatial resolution. In vitro evaluation of tracers showed that MPI performance of our MNTs is preserved in blood, serum-rich cell-culture medium and gel; thus independent of changes in hydrodynamic volume and fluid viscosity – a critical prerequisite for in vivo MPI. In a rodent model, our MNTs circulated for 15 min – 3× longer than Resovist – and supported our in vitro evaluation that MPI signal is preserved in the physiological environment. Furthermore, MRI and histology analysis showed that MNTs distribute in the reticuloendothelial system (RES) in a manner similar to clinically approved SPIO agents. MNTs demonstrating long-circulation times and optimized MPI performance show potential as angiography tracers and blood-pool agents for the emerging MPI imaging modality.
Guibin Jiang - One of the best experts on this subject based on the ideXlab platform.
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preparation of silica Magnetite Nanoparticle mixed hemimicelle sorbents for extraction of several typical phenolic compounds from environmental water samples
Journal of Chromatography A, 2008Co-Authors: Xiaoli Zhao, Thanh Wang, Guibin JiangAbstract:A novel type of superparamagnetic silica-coated (Fe3O4/SiO2 core/shell) Magnetite Nanoparticle modified by surfactants has been successfully synthesized and was applied as an effective sorbent material for the pre-concentration of several typical phenolic compounds (bisphenol A (BPA), 4-tert-octylphenol (4-OP) and 4-n-nonylphenol (4-NP)) from environmental water samples. Compared with pure magnetic particles, a thin and dense silica layer would protect the iron oxide core from leaching out in acidic conditions. In order to enhance their adsorptive tendency towards organic compounds, cetylpyridinium chloride (CPC) or cetyltrimethylammonium bromide (CTAB) were added, which adsorbed on the surface of the Fe3O4/SiO2 Nanoparticles (Fe3O4/SiO2 NPs) and formed mixed hemimicelles. Main factors affecting the adsolubilization of analytes were optimized and comparative study on the use of CPC and CTAB-coated Fe3O4/SiO2 NPs mixed hemimicelles-based SPE was also carried out. CPC-coated Fe3O4/SiO2 NPs system was selected due to lower elution volume required and more effective adsorption of the target compounds. Under selected conditions, concentration factor of 1600 was achieved by using this method to extract 800 mL of different environmental water samples. The detection limits obtained for BPA, 4-OP and 4-NP with HPLC-FLD were 7, 14, and 20 ng/L, respectively.
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preparation of silica Magnetite Nanoparticle mixed hemimicelle sorbents for extraction of several typical phenolic compounds from environmental water samples
Journal of Chromatography A, 2008Co-Authors: Xiaoli Zhao, Thanh Wang, Yali Shi, Yaqi Cai, Guibin JiangAbstract:A novel type of superparamagnetic silica-coated (Fe3O4/SiO2 core/shell) Magnetite Nanoparticle modified by surfactants has been successfully synthesized and was applied as an effective sorbent material for the pre-concentration of several typical phenolic compounds (bisphenol A (BPA), 4-tert-octylphenol (4-OP) and 4-n-nonylphenol (4-NP)) from environmental water samples. Compared with pure magnetic particles, a thin and dense silica layer would protect the iron oxide core from leaching out in acidic conditions. In order to enhance their adsorptive tendency towards organic compounds, cetylpyridinium chloride (CPC) or cetyltrimethylammonium bromide (CTAB) were added, which adsorbed on the surface of the Fe3O4/SiO2 Nanoparticles (Fe3O4/SiO2 NPs) and formed mixed hemimicelles. Main factors affecting the adsolubilization of analytes were optimized and comparative study on the use of CPC and CTAB-coated Fe3O4/SiO2 NPs mixed hemimicelles-based SPE was also carried out. CPC-coated Fe3O4/SiO2 NPs system was selected due to lower elution volume required and more effective adsorption of the target compounds. Under selected conditions, concentration factor of 1600 was achieved by using this method to extract 800 mL of different environmental water samples. The detection limits obtained for BPA, 4-OP and 4-NP with HPLC-FLD were 7, 14, and 20 ng/L, respectively.
Amit P Khandhar - One of the best experts on this subject based on the ideXlab platform.
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tuning surface coatings of optimized Magnetite Nanoparticle tracers for in vivo magnetic particle imaging
IEEE Transactions on Magnetics, 2015Co-Authors: Amit P Khandhar, Matthew R Ferguson, Hamed Arami, Scott Jeffrey Kemp, Kannan M KrishnanAbstract:Surface coatings are important components of magnetic particle imaging (MPI) tracers—they preserve their key properties responsible for optimum tracer performance in physiological environments. In vivo , surface coatings form a physical barrier between the hydrophobic superparamagnetic iron oxide Nanoparticles (SPION) cores and the physiological environment, and their design dictates the blood half-life and biodistribution of MPI tracers. Here, we show the effect of tuning poly(ethylene glycol) (PEG)-based surface coatings on both in vitro and in vivo (mouse model) MPI performance of SPIONs. Our results showed that varying PEG molecular weight had a profound impact on colloidal stability, characterized using dynamic light scattering, and the m’ ( H ) response of SPIONs, measured in a 25 kHz/20 mT $ \mu _{\text {0}}^{\text {-1}}{}_{ {\rm max}}$ magnetic particle spectrometer. Increasing PEG molecular weight from 5 to 20 kDa preserved colloidal stability and m’ ( H ) response of ${\sim } \text{25}$ nm SPIONs—the optimum core diameter for MPI—in serum-rich cell culture medium for up to 24 h. Furthermore, we compared the in vivo circulation time of SPIONs as a function of hydrodynamic diameter and showed that clustered SPIONs can adversely affect blood half-life; critically, SPIONs with clusters had five times shorter blood half-life than individually coated SPIONs. We anticipate that the development of MPI SPION tracers with long blood half-lives have potential not only in vascular imaging applications, but also enable opportunities in molecular targeting and imaging—a critical step toward early cancer detection using the new MPI modality.
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Drive-Field Frequency Dependent MPI Performance of Single-Core Magnetite Nanoparticle Tracers
IEEE Transactions on Magnetics, 2015Co-Authors: Christian Kuhlmann, Meinhard Schilling, Amit P Khandhar, Kannan M Krishnan, Richard Matthew Ferguson, Scott Kemp, Thilo Wawrzik, Frank LudwigAbstract:The drive-field frequency of magnetic particle imaging (MPI) systems plays an important role for system design, safety requirements, and tracer selection. Because the commonly utilized MPI drive-field frequency of 25 kHz might be increased in future system generations to avoid peripheral nerve stimulation, a performance evaluation of tracers at higher frequencies is desirable. We have studied single-core Magnetite Nanoparticles that were optimized for MPI applications, utilizing magnetic particle spectrometers (MPS) with drive-field frequencies in the range from 1 to 100 kHz. The particles have core diameters of 25 nm and a hydrodynamic size of 77 nm. Measurements in the frequency range above 5 kHz were carried out with a newly designed MPS system. In addition, to exclude possible particle interaction, samples of different concentrations were characterized and compared.
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monodisperse Magnetite Nanoparticle tracers for in vivo magnetic particle imaging
Biomaterials, 2013Co-Authors: Amit P Khandhar, Matthew R Ferguson, Hamed Arami, Kannan M KrishnanAbstract:Magnetic Particle Imaging (MPI) is a new biomedical imaging modality that produces real-time, highresolution tomographic images of superparamagnetic iron oxide (SPIO) Nanoparticle tracer distributions. In this study, we synthesized monodisperse tracers for enhanced MPI performance and investigated both, their blood clearance time using a 25 kHz magnetic particle spectrometer (MPS), and biodistribution using a combination of quantitative T2-weighted MRI and tissue histology. In vitro and in vivo MPI performance of our magnetic Nanoparticle tracers (MNTs), subject to biological constraints, were compared to commercially available SPIOs (Resovist). Monodisperse MNTs showed a 2-fold greater signal per unit mass, and 20% better spatial resolution. In vitro evaluation of tracers showed that MPI performance of our MNTs is preserved in blood, serum-rich cell-culture medium and gel; thus independent of changes in hydrodynamic volume and fluid viscosity e a critical prerequisite for in vivo MPI. In a rodent model, our MNTs circulated for 15 min e 3� longer than Resovist e and supported our in vitro evaluation that MPI signal is preserved in the physiological environment. Furthermore, MRI and histology analysis showed that MNTs distribute in the reticuloendothelial system (RES) in a manner similar to clinically approved SPIO agents. MNTs demonstrating long-circulation times and optimized MPI performance show potential as angiography tracers and blood-pool agents for the emerging MPI imaging modality.
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monodisperse Magnetite Nanoparticle tracers for in vivo magnetic particle imaging
Biomaterials, 2013Co-Authors: Amit P Khandhar, Matthew R Ferguson, Hamed Arami, Kannan M KrishnanAbstract:Abstract Magnetic Particle Imaging (MPI) is a new biomedical imaging modality that produces real-time, high-resolution tomographic images of superparamagnetic iron oxide (SPIO) Nanoparticle tracer distributions. In this study, we synthesized monodisperse tracers for enhanced MPI performance and investigated both, their blood clearance time using a 25 kHz magnetic particle spectrometer (MPS), and biodistribution using a combination of quantitative T2-weighted MRI and tissue histology. In vitro and in vivo MPI performance of our magnetic Nanoparticle tracers (MNTs), subject to biological constraints, were compared to commercially available SPIOs (Resovist). Monodisperse MNTs showed a 2-fold greater signal per unit mass, and 20% better spatial resolution. In vitro evaluation of tracers showed that MPI performance of our MNTs is preserved in blood, serum-rich cell-culture medium and gel; thus independent of changes in hydrodynamic volume and fluid viscosity – a critical prerequisite for in vivo MPI. In a rodent model, our MNTs circulated for 15 min – 3× longer than Resovist – and supported our in vitro evaluation that MPI signal is preserved in the physiological environment. Furthermore, MRI and histology analysis showed that MNTs distribute in the reticuloendothelial system (RES) in a manner similar to clinically approved SPIO agents. MNTs demonstrating long-circulation times and optimized MPI performance show potential as angiography tracers and blood-pool agents for the emerging MPI imaging modality.
Akira Ito - One of the best experts on this subject based on the ideXlab platform.
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Magnetite Nanoparticle loaded anti her2 immunoliposomes for combination of antibody therapy with hyperthermia
Cancer Letters, 2004Co-Authors: Akira Ito, Yuko Kuga, Hiroyuki Honda, Hiroyuki Kikkawa, Atsushi Horiuchi, Yuji Watanabe, Takeshi KobayashiAbstract:Abstract Anti-HER2 antibody can induce antitumor responses, and can be used in delivering drugs to HER2-overexressing cancer. Previously, we produced hyperthermia using Magnetite Nanoparticles that generate heat in an alternating magnetic field. In the present study, we constructed anti-HER2 immunoliposomes containing Magnetite Nanoparticles, which act as tumor-targeting vehicles, combining anti-HER2 antibody therapy with hyperthermia. The Magnetite Nanoparticle-loaded anti-HER2 immunoliposomes exerted HER2-mediated antiproliferative effects on SKBr3 breast cancer cells in vitro. Moreover, 60% of Magnetite Nanoparticles were incorporated into SKBr3, and the cells were then heated at 42.5 °C under an alternating magnetic field, resulting in strong cytotoxic effects. These results suggest that this novel therapeutic tool is applicable to treatment of HER2-overexpressing cancer.
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Magnetite Nanoparticle loaded anti her2 immunoliposomes for combination of antibody therapy with hyperthermia
Cancer Letters, 2004Co-Authors: Akira Ito, Yuko Kuga, Hiroyuki Honda, Hiroyuki Kikkawa, Atsushi Horiuchi, Yuji Watanabe, Takeshi KobayashiAbstract:Anti-HER2 antibody can induce antitumor responses, and can be used in delivering drugs to HER2-overexpressing cancer. Previously, we produced hyperthermia using Magnetite Nanoparticles that generate heat in an alternating magnetic field. In the present study, we constructed anti-HER2 immunoliposomes containing Magnetite Nanoparticles, which act as tumor-targeting vehicles, combining anti-HER2 antibody therapy with hyperthermia. The Magnetite Nanoparticle-loaded anti-HER2 immunoliposomes exerted HER2-mediated antiproliferative effects on SKBr3 breast cancer cells in vitro. Moreover, 60% of Magnetite Nanoparticles were incorporated into SKBr3, and the cells were then heated at 42.5 degrees C under an alternating magnetic field, resulting in strong cytotoxic effects. These results suggest that this novel therapeutic tool is applicable to treatment of HER2-overexpressing cancer.