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Paranawithana NN, Chiaffarelli R, Kretschmer J, Buchanan E, Lopez K, Zhao P, Kiefer G, Jurek P, Martins AF, Sherry AD. Enhancing r1 Relaxivity in GdDOTA-Monoamide Complexes through Polar Group-Mediated Ordering of Second-Sphere Water Molecules. Inorg Chem 2024; 63:4072-4077. [PMID: 38385753 DOI: 10.1021/acs.inorgchem.3c03639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
This study was designed to test whether the single appended phosphonate group in GdDOTA-1AmP is sufficient for catalyzing the exchange of proton from the single inner-sphere water-exchanging molecule. Unlike the other phosphonate derivatives in this series, GdDOTA-1AmP showed a surprisingly smooth increase in r1 relaxivity from 3.0 to 6.3 mM-1 s-1 at 20 MHz as the pH was lowered from 9 to 2.5. In comparison to the bis-, tris-, and tetrakis-phosphonate analogues, which all show a biphasic dependence of r1 with changes in pH, the unique r1 versus pH characteristics of GdDOTA-1AmP are shown to closely parallel deprotonation of the single appended phosphonate group. Although the tissue biodistribution and clearance rates of GdDOTA-1AmP are more favorable than the other more highly charged phosphonate derivatives, the pH dependency of r1 is substantially reduced at magnetic fields typically used for small animal imaging (7 and 9.4T), so the attractiveness of this new molecule for quantitative imaging of tissue pH is diminished. However, this study provides some new insights into the feasibility of designing pH-responsive MRI contrast agents based upon fundamental acid-base prototropic mechanisms.
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Affiliation(s)
- Namini N Paranawithana
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Remy Chiaffarelli
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies″, University of Tübingen, Tübingen 72076, Germany
- German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Jan Kretschmer
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies″, University of Tübingen, Tübingen 72076, Germany
- German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Emily Buchanan
- Macrocyclics, Inc., An Orano Med Company, 700 Klein Road, Plano, Texas 75074, United States
| | - Katherine Lopez
- Macrocyclics, Inc., An Orano Med Company, 700 Klein Road, Plano, Texas 75074, United States
| | - Piyu Zhao
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Garry Kiefer
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
- Macrocyclics, Inc., An Orano Med Company, 700 Klein Road, Plano, Texas 75074, United States
| | - Paul Jurek
- Macrocyclics, Inc., An Orano Med Company, 700 Klein Road, Plano, Texas 75074, United States
| | - André F Martins
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies″, University of Tübingen, Tübingen 72076, Germany
- German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, United States
| | - A Dean Sherry
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, United States
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Mallik R, Khannam M, Saha M, Marandi S, Kumar S, Mukherjee C. The electrostatic confinement of aquated monocationic Gd(III) complex-molecules within the inner core of porous silica nanoparticles creates a highly efficient T1 contrast agent for magnetic resonance imaging. Dalton Trans 2022; 51:14138-14149. [PMID: 36043989 DOI: 10.1039/d2dt02272a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Contrast-agent enhanced magnetic resonance imaging (MRI) has been under continuous investigation for the conspicuous imaging of lesions and the early-stage detection of tumors. To achieve the development of a T1-weighted contrast agent with a high relaxivity value, herein, porous silica nanoparticles that had internalized about 20 aquated cationic Gd(III) complexes (1) of the hexadentate hydroxyethyl-appended picolinate-based ligand H2hbda were demonstrated. Complex 1 exhibited a longitudinal relaxivity value per mM Gd(III) ions, r1, of 9.05 mM-1 s-1 (pH 7.4, 37 °C, 1.41 T), which increased to 86.41 mM-1 s-1 because of the grafting of complex 1 in the inner core of porous silica nanospheres through electrostatic interactions between the anionic silica surface and the cationic complex 1 molecules. A further augmentation in the relaxivity value to 118.32 mM-1 s-1 was realized because of the interaction of the complex 1@SiO2NPs with serum albumin protein. The synthesized nanosystem was impervious to physiologically available anions (HPO42- and HCO31-) and also kinetically inert, as evidenced via a transmetallation experiment in the presence of Zn(II) ions. The developed complex-incorporated nanomaterial was bio- and hemo-compatible. Cellular uptake measurements employing HeLa cells and the concentration-dependent enhancement in the brightness of in vitro phantom images, recorded under a clinical scanner at 1.5 T, demonstrated that the developed biocompatible 1@SiO2NP complex has promising diagnostic applications as a T1-weighted MRI contrast agent.
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Affiliation(s)
- Riya Mallik
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
| | - Mahmuda Khannam
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
| | - Muktashree Saha
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Shivani Marandi
- Centre for the Environment, Indian Institute of Technology Guwahati, Assam-781039, India
| | - Sachin Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Chandan Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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