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The Emergence of “Magnetic and Fluorescent” Multimodal Nanoparticles as Contrast Agents in Bioimaging
Published in Wolfgang Sigmund, Hassan El-Shall, Dinesh O. Shah, Brij M. Moudgil, Particulate Systems in Nano- and Biotechnologies, 2008
P. Sharma, A. Singh, S.C. Brown, G.A. Walter, S. Santra, S.R. Grobmyer, E.W. Scott, B.M. Moudgil
Some examples of multimodal imaging agents are found on the market and many more are expected to become available in the near future. Commercially available Gadolinium (Gd) chelates,29,30 gadolinium oxide microspheres,31,32 and iron nanoparticles33 have been evaluated as contrast agents for MRI/CT. From our research group, Gd-doped fluorescent core nanoparticles have been demonstrated as a contrast agent for MRI/CT/OI.34,35 Others have combined CT with PET via the use of multimodal agents. PET provides functional and metabolic information, whereas CT provides information about anatomical details with high spatial resolution.36 PET/CT imaging is being increasingly used for clinical diagnosis, monitoring cancer staging and treatment.37,38μCT and bioluminescence imaging have been used together in a murine model to detect early tumor-bone destruction, demonstrating an effective combination of high sensitivity and quantitative morphological estimation.39
Stimuli-Regulated Cancer Theranostics Based on Magnetic Nanoparticles
Published in Nguyễn T. K. Thanh, Clinical Applications of Magnetic Nanoparticles, 2018
Yanmin Ju, Shiyan Tong, Yanglong Hou
Gd-chelates, for example, Gd-diethylenetriaminepentaacetic acid (Gd-DTPA) and Gd- N,N′,N″,N‴-tetracarboxymethyl-1,4,7,10-tetraazacyclododecane (Gd-DOTA) are the most widely used T1-weighted contrast agents for clinical therapy. However, it has relatively low r1 value and short retention time in vivo. Besides, the toxicity and biocompatibility after entering into the body still need to be solved.85 In order to reduce the toxicity of Gd3+ and enhance the T1-weighted MR signal, efforts have been devoted to incorporate Gd3+ with NPs, which can also increase the cellular uptake of Gd3+ by tuning the size and shape of NPs.83,86 Gd-chelate grafted inorganic NPs have been developed and can even behave as contrast agents for multimodality imaging for cancer therapy.87 Xia et al. have designed a kind of core-shell NP, with up conversion nanoparticles (UCNPs) as the core and SiO2 as the shell layer, and Gd-DTPA as the surface ligand for upconversion luminescence, computed tomography (CT) and T1-weighted MR trimodality in vivo imaging.88 Inorganic NPs containing Gd3+, such as gadolinium oxide (Gd2O3), gadolinium phosphate (GdPO4) and gadolinium fluoride (GdF3) have recently been utilized as T1-weighted MRI contrast agents in cancer therapy.89–91 Compared to Gd-chelate grafted NPs, these NPs have the ability to carry large payloads of active magnetic centres and increase relaxivity values. For example, ultrasmall paramagnetic Gd2O3 NPs, with an average diameter of 1 nm can act as T1 positive contrast agents.92
Non-isothermal kinetics of the thermal decomposition of gadolinium nitrate
Published in Journal of Nuclear Science and Technology, 2018
Tatsuya Fukuda, Yoshio Nakano, Kenji Takeshita
The XRD patterns of denitrate products (at 420, 700°C) are illustrated in Figure 3. Denitration XRD patterns of dehydrated gadolinium suggested gadolinium oxide nitrate (GdO(NO3)) at 420°C and gadolinium oxide (Gd2O3) at 700°C. The morphology of gadolinium compound denitrated at 520°C couldn’t be identified, however, 9%-weight-loss in the temperature range of 400–500°C and Melnikov’s report [9] support that gadolinium oxide nitrate was decomposed to the gadolinium compound which seems to be Gd4O5(NO3)2 in the temperature around 500°C, and it decomposes to gadolinium oxide in the temperature range around 600°C.