scholarly journals Characterization of Co(II)-PAMAM dendrimer complexes with polypropylene oxide core by using UV-VIS spectroscopy

2016 ◽  
Vol 35 (2) ◽  
pp. 263 ◽  
Author(s):  
Ali Serol Ertürk ◽  
Mustafa Ulvi Gürbüz ◽  
Metin Tülü ◽  
Abdürrezzak Emin Bozdoğan
Keyword(s):  
Pamam Dendrimer ◽  
Mri Contrast Agents ◽  
Mri Contrast ◽  
Polypropylene Oxide ◽  
Vis Spectroscopy ◽  
Complexation Agent ◽  
Titration Data ◽  
Spectroscopic Titration ◽  
Optimized Conditions

<p>The aim of this study was to characterize poly(amidoamine) (PAMAM) dendrimer complexes of Co(II) ions by using UV-Vis spectroscopy. For this aim, a generation-4 polypropylene oxide (Jeffamine<sup>®</sup> T-403) cored and amine-terminated PAMAM dendrimer (P<sub>4</sub>) was used as a model complexation agent. Optimum complexation condition for P<sub>4</sub> was determined by potentiometric and spectroscopic titration studies. Extent of protonation (EOP) of the amino groups of P<sub>4</sub> was determined from the potentiometric titration data and validated with spectroscopic titration data. The results indicated that pH 8 was the optimum dendrimer aqueous solution media, where the available number of tertiary amines present in P<sub>4 </sub>was the highest for possible metal complexation. At the optimized conditions, UV-Vis characterization of the Co(II)-P<sub>4</sub> complexes was performed and 585–635 nm <em>d-d</em> transition bands were observed as the characteristic complexation bands of the tertiary amine groups of P<sub>4</sub> with Co(II) ions. Obtained Co(II)-P<sub>4</sub> complexes might be considered for the development of magnetic resonance image (MRI) improvers or MRI contrast agents.</p><p class="Abstract"><span lang="EN-US"><br /></span></p>

Synthesis and characterization of a new water-soluble endohedral metallofullerene for MRI contrast agents

Carbon ◽  
2006 ◽  
Vol 44 (3) ◽  
pp. 496-500 ◽  
Author(s):  
Chun-Ying Shu ◽  
Li-Hua Gan ◽  
Chun-Ru Wang ◽  
Xin-long Pei ◽  
Hong-bin Han
Keyword(s):  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Mri Contrast ◽  
Endohedral Metallofullerene

scholarly journals A Photocleavable Contrast Agent for Light-Responsive MRI

2020 ◽  
Vol 13 (10) ◽  
pp. 296
Author(s):  
Friederike Reeßing ◽  
Sèvrin E. M. Huijsse ◽  
Rudi A. J. O. Dierckx ◽  
Ben L. Feringa ◽  
Ronald J.H. Borra ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Whole Body ◽  
Spatiotemporal Resolution ◽  
Mri Contrast ◽  
High Relaxivity ◽  
Vis Spectroscopy ◽  
Clinical Mri

Thanks to its innocuousness and high spatiotemporal resolution, light is used in several established and emerging applications in biomedicine. Among them is the modulation of magnetic resonance imaging (MRI) contrast agents’ relaxivity with the aim to increase the sensitivity, selectivity and amount of functional information obtained from this outstanding whole-body medical imaging technique. This approach requires the development of molecular contrast agents that show high relaxivity and strongly pronounced photo-responsiveness. To this end, we report here the design and synthesis of a light-activated MRI contrast agent, together with its evaluation using UV–vis spectroscopy, Fast Field Cycling (FFC) relaxometry and relaxometric measurements on clinical MRI scanners. The high relaxivity of the reported agent changes substantially upon irradiation with light, showing a 17% decrease in relaxivity at 0.23T upon irradiation with λ = 400 nm (violet) light for 60 min. On clinical MRI scanners (1.5T and 3.0T), irradiation leads to a decrease in relaxivity of 9% and 19% after 3 and 60 min, respectively. The molecular design presents an important blueprint for the development of light-activatable MRI contrast agents.

Synthesis and characterization of pH-sensitive, biotinylated MRI contrast agents and their conjugates with avidin

2013 ◽  
Vol 11 (8) ◽  
pp. 1294-1305 ◽  
Author(s):  
Sandip M. Vibhute ◽  
Jörn Engelmann ◽  
Tatjana Verbić ◽  
Martin E. Maier ◽  
Nikos K. Logothetis ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Ph Sensitive ◽  
Synthesis And Characterization ◽  
Mri Contrast

scholarly journals High Current Density Chronopotentiometric Electrosynthesis and SEM Characterization of Hexanethiol-Monolayer-Protected Silver Planar Nanotriangles (Ag@C6SH)

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
DJafar Vatan Khah Dowlat Sara ◽  
Ahmad Rouhollahi ◽  
Seied Mahdi Pourmortazavi ◽  
Mojtaba Shamsipur
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Average Particle Size ◽  
Average Particle ◽  
Nonaqueous Media ◽  
Experimental Conditions ◽  
Vis Spectroscopy ◽  
Optimized Conditions ◽  
First Time

This work reports for the first time electrosynthesis of hexanethiol capped silver nanotriangles cores (Ag@C6SH NCs) by a rapid, clean, and simple Double Pulse Chronopotentiometric (DCP) method in nonaqueous media, using a Taguchi orthogonal arrayL8design to identify the optimized experimental conditions. It was found that the size and shape of the product could be tuned by the current density, electrolysis time, electrode distance, and amount of NaBH4% used. The Ag@C6SH NCs in different shapes and sizes (in the range of 30 to 44 nm as an average estimation) were synthesized, under different experimental conditions. Finally, the as-prepared nanoclusters electrosynthesized at optimized conditions were characterized by SEM, XRD, and UV-Vis spectroscopy. The average particle size of the triangular/pyramidal shape (Ag@C6SH NCs), obtained under optimized experimental conditions, was30.5±2.0 nm but the majority of nanoparticles in TC3SEM are so much finer.

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