3d-scanning-technology-bridging-microcircuits-macroscale-brain-images

3D Scanning Technology Bridging Microcircuits and Macroscale Brain Images in 3D Novel Embedding Overlapping Protocol

The human brain, being a multiscale system, has both macroscopic electrical signals, globally flowing along thick white-matter fiber bundles, and ...

Kyoto University

Recently, we developed novel chiral dendrimer-triamine-coordinated Gd-MRI contrast agents (Gd-MRI CAs), which showed longitudinal relaxivity (r₁) values about four times higher than that of clinically used Gd-DTPA (Magnevist(®), Bayer). In our continuing study of pharmacokinetic differences derived from both the chirality and generation of Gd-MRI CAs, we found that the ability of chiral dendrimer Gd-MRI CAs to circulate within the body can be directly evaluated by in vitro MRI (7 T). In this study, the association constants (K(a)) of chiral dendrimer Gd-MRI CAs to bovine serum albumin (BSA), measured and calculated with a quartz crystal microbalance (QCM) in vitro, were found to be an extremely easy means for evaluating the body-circulation ability of chiral dendrimer Gd-MRI CAs. The K(a) values of S-isomeric dendrimer Gd-MRI CAs were generally greater than those of R-isomeric dendrimer Gd-MRI CAs, which is consistent with the results of our previous MRI study in vivo.

Pharmacokinetics of Chiral Dendrimer-Triamine-Coordinated Gd-MRI Contrast Agents Evaluated by in Vivo MRI and Estimated by in Vitro QCM.

Metal-free magnetic mixed micelles (mean diameter: < 20 nm) were prepared by mixing the biocompatible non-ionic surfactant Tween 80 and the non-toxic, hydrophobic pyrrolidine--oxyl radicals bearing a D-glucosamine unit in pH 7.4 phosphate-buffered saline (PBS). The time-course stability and  magnetic resonance imaging (MRI) contrast ability of the mixed micelles was found to depend on the length of the alkyl chain in the nitroxide radicals. It was also confirmed that the mixed micelles exhibited no toxicity  and  and high stability in the presence of a large excess of ascorbic acid. The  MRI experiment revealed that one of these mixed micelles showed much higher contrast enhancement in the proton longitudinal relaxation time (₁) weighted images than other magnetic mixed micelles that we have reported previously. Thus, the magnetic mixed micelles presented here are expected to serve as a promising contrast agent for theranostic nanomedicines, such as MRI-visible targeted drug delivery carriers.

Magnetic Mixed Micelles Composed of a Non-Ionic Surfactant and Nitroxide Radicals Containing a D-Glucosamine Unit: Preparation, Stability, and Biomedical Application.

Article	Year
Pharmacokinetics of Chiral Dendrimer-Triamine-Coordinated Gd-MRI Contrast Agents Evaluated by in Vivo MRI and Estimated by in Vitro QCM. Sensors (Basel, Switzerland)\| PubMed ID: 26694418	2015
Magnetic Mixed Micelles Composed of a Non-Ionic Surfactant and Nitroxide Radicals Containing a D-Glucosamine Unit: Preparation, Stability, and Biomedical Application. Pharmaceutics\| PubMed ID: 30669485	2019
Stability Enhancement of Xe Hyperpolarizing System That uses Alkali Metal Vapor in Spin-Exchange Optical Pumping Cell to achieve High NMR Sensitivity. Analytical sciences : the international journal of the Japan Society for Analytical Chemistry\| PubMed ID: 30982799	2019

Hirohiko Imai

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