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Jiang L, Cai Z, Cao Y, Fu S, Gu H, Zhu J, Cao W, Zhong L, Zhong J, Wu C, Wang K, Xia C, Lui S, Song B, Gong Q, Ai H. Facile Synthesis of Rigid Binuclear Manganese Complexes for Magnetic Resonance Angiography and SLC39A14-Mediated Hepatic Imaging. Bioconjug Chem 2024; 35:703-714. [PMID: 38708860 DOI: 10.1021/acs.bioconjchem.4c00185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Manganese(II)-based contrast agents (MBCAs) are potential candidates for gadolinium-free enhanced magnetic resonance imaging (MRI). In this work, a rigid binuclear MBCA (Mn2-PhDTA2) with a zero-length linker was developed via facile synthetic routes, while the other dimer (Mn2-TPA-PhDTA2) with a longer rigid linker was also synthesized via more complex steps. Although the molecular weight of Mn2-PhDTA2 is lower than that of Mn2-TPA-PhDTA2, their T1 relaxivities are similar, being increased by over 71% compared to the mononuclear Mn-PhDTA. In the presence of serum albumin, the relaxivity of Mn2-PhDTA2 was slightly lower than that of Mn2-TPA-PhDTA2, possibly due to the lower affinity constant. The transmetalation reaction with copper(II) ions confirmed that Mn2-PhDTA2 has an ideal kinetic inertness with a dissociation half-life of approximately 10.4 h under physiological conditions. In the variable-temperature 17O NMR study, both Mn-PhDTA and Mn2-PhDTA2 demonstrated a similar estimated q close to 1, indicating the formation of monohydrated complexes with each manganese(II) ion. In addition, Mn2-PhDTA2 demonstrated a superior contrast enhancement to Mn-PhDTA in in vivo vascular and hepatic MRI and can be rapidly cleared through a dual hepatic and renal excretion pattern. The hepatic uptake mechanism of Mn2-PhDTA2 mediated by SLC39A14 was validated in cellular uptake studies.
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Affiliation(s)
- Lingling Jiang
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610065, China
| | - Zhongyuan Cai
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610065, China
| | - Yingzi Cao
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610065, China
| | - Shengxiang Fu
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Haojie Gu
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610065, China
| | - Jiang Zhu
- Sichuan Key Laboratory of Medical Imaging, North Sichuan Medical College, Nanchong 637000, China
| | - Weidong Cao
- Sichuan Key Laboratory of Medical Imaging, North Sichuan Medical College, Nanchong 637000, China
| | - Lei Zhong
- Sichuan Key Laboratory of Medical Imaging, North Sichuan Medical College, Nanchong 637000, China
| | - Jie Zhong
- Sichuan Key Laboratory of Medical Imaging, North Sichuan Medical College, Nanchong 637000, China
| | - Changqiang Wu
- Sichuan Key Laboratory of Medical Imaging, North Sichuan Medical College, Nanchong 637000, China
| | - Kefeng Wang
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610065, China
| | - Chunchao Xia
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Su Lui
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Bin Song
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Psychoradiology Research Unit of Chinese Academy of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Hua Ai
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610065, China
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
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Henoumont C, Devreux M, Laurent S. Mn-Based MRI Contrast Agents: An Overview. Molecules 2023; 28:7275. [PMID: 37959694 PMCID: PMC10648041 DOI: 10.3390/molecules28217275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
MRI contrast agents are required in the clinic to detect some pathologies, such as cancers. Nevertheless, at the moment, only small extracellular and non-specific gadolinium complexes are available for clinicians. Moreover, safety issues have recently emerged concerning the use of gadolinium complexes; hence, alternatives are urgently needed. Manganese-based MRI contrast agents could be one of these alternatives and increasing numbers of studies are available in the literature. This review aims at synthesizing all the research, from small Mn complexes to nanoparticular agents, including theranostic agents, to highlight all the efforts already made by the scientific community to obtain highly efficient agents but also evidence of the weaknesses of the developed systems.
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Affiliation(s)
- Céline Henoumont
- NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, 19 Avenue Maistriau, 7000 Mons, Belgium; (C.H.)
| | - Marie Devreux
- NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, 19 Avenue Maistriau, 7000 Mons, Belgium; (C.H.)
| | - Sophie Laurent
- NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, 19 Avenue Maistriau, 7000 Mons, Belgium; (C.H.)
- Center for Microscopy and Molecular Imaging (CMMI), 8 Rue Adrienne Boland, 6041 Gosselies, Belgium
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Pota K, Johnston HM, Madarasi E, Tircsó G, Green KN. Synthesis and characterization of two piperazine containing macrocycles and their transition metal complexes. J Inorg Biochem 2023; 241:112124. [PMID: 36652846 PMCID: PMC10019750 DOI: 10.1016/j.jinorgbio.2023.112124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 01/11/2023]
Abstract
Rigidification of the ligand scaffolds has been a particular mechanism of interest employed to achieve properties suitable for MRI contrast, catalysis, or other applications of metal complexes. Towards the goal of targeting a 15-anePyN5Pip type ligand, a serendipitous isolation of a 30-anePy2N10Pip2 aza-macrocycle was achieved, instead. X-ray diffraction and determination of pKa events were carried out and compared to 17-anePyN5Pip. Furthermore, the X-ray diffraction of the Cu(II) and Zn(II) complexes of 17-anePyN5Pip was achieved and compared to previous reports of other first-row transition metal derivatives of this ligand. Determination of the log β with both 30-anePy2N10Pip2 and 17-anePyN5Pip with the divalent MnZn metal-ion series was used to demonstrate the impact that the piperazine ring plays compared to other, less rigid macrocycles reported to date.
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Affiliation(s)
- Kristof Pota
- Texas Christian University, Department of Chemistry and Biochemistry, 2950 W. Bowie, Fort Worth, TX 76129
| | - Hannah M. Johnston
- Texas Christian University, Department of Chemistry and Biochemistry, 2950 W. Bowie, Fort Worth, TX 76129
| | - Enikő Madarasi
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1., Debrecen, Hungary H-4032
- Doctoral School of Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, Hungary H-4032
| | - Gyula Tircsó
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1., Debrecen, Hungary H-4032
| | - Kayla N. Green
- Texas Christian University, Department of Chemistry and Biochemistry, 2950 W. Bowie, Fort Worth, TX 76129
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Daksh S, Kaul A, Deep S, Datta A. Current advancement in the development of manganese complexes as magnetic resonance imaging probes. J Inorg Biochem 2022; 237:112018. [PMID: 36244313 DOI: 10.1016/j.jinorgbio.2022.112018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/14/2022] [Accepted: 09/28/2022] [Indexed: 01/18/2023]
Abstract
Emerging non-invasive molecular imaging modalities can detect a pathophysiological state at the molecular level before any anatomic changes are observed. Magnetic resonance imaging (MRI) is preferred over other nuclear imaging techniques owing to its radiation-free approach. Conventionally, most MRI contrast agents employed predominantly involve lanthanide metal: Gadolinium (Gd) until the discovery of associated severe nephrogenic toxicity issues. This limitation led a way to the development of manganese-based contrast agents which offer similar positive contrast enhancement capability. A vast quantity of experimental data has been accumulated over the last decade to define the physicochemical characteristics of manganese chelates with various ligand scaffolds. One can now observe how the ligand configurations, rigidity, and donor-acceptor characteristics impact the stability of the complex. This review covers the current trends in the development of manganese-based MRI contrast agents, the mechanisms they are based on and design considerations for newer manganese-based contrast agents with higher diagnostic strength along with better safety profiles.
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Affiliation(s)
- Shivani Daksh
- Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organization, Brig S. K. Mazumdar Marg, Delhi 110054, India; Department of Chemistry, Indian Institute of Technology, Hauz-Khas, New Delhi 110016, India
| | - Ankur Kaul
- Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organization, Brig S. K. Mazumdar Marg, Delhi 110054, India
| | - Shashank Deep
- Department of Chemistry, Indian Institute of Technology, Hauz-Khas, New Delhi 110016, India.
| | - Anupama Datta
- Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organization, Brig S. K. Mazumdar Marg, Delhi 110054, India.
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Uzal-Varela R, Pérez-Fernández F, Valencia L, Rodríguez-Rodríguez A, Platas-Iglesias C, Caravan P, Esteban-Gómez D. Thermodynamic Stability of Mn(II) Complexes with Aminocarboxylate Ligands Analyzed Using Structural Descriptors. Inorg Chem 2022; 61:14173-14186. [PMID: 35994514 PMCID: PMC9455602 DOI: 10.1021/acs.inorgchem.2c02364] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We present a quantitative analysis of the thermodynamic
stabilities
of Mn(II) complexes, defined by the equilibrium constants (log KMnL values) and the values of pMn obtained as
−log[Mn]free for total metal and ligand concentrations
of 1 and 10 μM, respectively. We used structural descriptors
to analyze the contributions to complex stability of different structural
motifs in a quantitative way. The experimental log KMnL and pMn values can be predicted to a good accuracy
by adding the contributions of the different motifs present in the
ligand structure. This allowed for the identification of features
that provide larger contributions to complex stability, which will
be very helpful for the design of efficient chelators for Mn(II) complexation.
This issue is particularly important to develop Mn(II) complexes for
medical applications, for instance, as magnetic resonance imaging
(MRI) contrast agents. The analysis performed here also indicates
that coordination number eight is more common for Mn(II) than is generally
assumed, with the highest log KMnL values generally observed for hepta- and octadentate ligands. The
X-ray crystal structure of [Mn2(DOTA)(H2O)2], in which eight-coordinate [Mn(DOTA)]2– units are bridged by six-coordinate exocyclic Mn(II) ions, is also
reported. We present empirical relationships
that allow estimating
the log K and pMn values of Mn(II) complexes
relevant as contrast agents for magnetic resonance imaging (MRI).
The prediction of complex stability with these expressions relies
on structural descriptors, providing a very powerful tool to aid with
ligand design.
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Affiliation(s)
- Rocío Uzal-Varela
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Francisco Pérez-Fernández
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Laura Valencia
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo, As Lagoas, Marcosende, 36310 Pontevedra, Spain
| | - Aurora Rodríguez-Rodríguez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Peter Caravan
- The Institute for Innovation in Imaging and the A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, 149, 13th Street, Suite 2301, Charlestown, Massachusetts 02129, United States
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
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Nagendraraj T, Kumaran SS, Mayilmurugan R. Mn(II) complexes of phenylenediamine based macrocyclic ligands as T 1-MRI contrast agents. J Inorg Biochem 2021; 228:111684. [PMID: 34929541 DOI: 10.1016/j.jinorgbio.2021.111684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 11/22/2021] [Accepted: 11/29/2021] [Indexed: 01/06/2023]
Abstract
The Mn(II) complexes are emerging as alternative T1-MRI contrast agents (CAs) to the currently available Gd-based CAs. The complexes [Mn(L1)] 1 and [Mn(L2)] 2 of o-phenylenediamine based macrocyclic ligands are reported as T1-CAs for MRI applications. The high spin state of the Mn(II) complexes (S = 5/2) is confirmed by EPR spectra. The complexes showed an irreversible Mn(II)/Mn(III) redox potential at pH 7.28, which became more and less positive at the acidic and alkaline pHs, respectively. The species [MnL], [Mn(LH-1), and [Mn(LH-2) are persisted in solution. Complex 1 is inert towards Ca(II), Mg(II), and Zn(II), whereas complex 2 is inert for Ca(II) and Mg(II) and labile under Zn(II) and Cu(II) ions. Complex 1 showed an r1-relaxivity of 3.27 and 2.32 mM-1 s-1 at 1.41 T, 25, and 37 °C respectively via inner-sphere water relaxation, which is lower than that of 2 (r1, 5.56, and 4.19 mM-1 s-1) at pH 7.28 and 1.41 T. The Mn(II) complexes showed a 2-8% enhancement of r1-relaxivity while lowering the pH to acidic, which corresponds to the release of free Mn(II) ions. In contrast, the r1-relaxivity is dropped to 52% and 20% for 1 and 2 respectively under alkaline pH due to the deprotonation of inner-sphere water. Phantom images obtained on Bruker 'BIOSPEC' 47/40 animal research MRI/MRS scanner showed concentration-dependent brightness. The interaction of human serum albumin (HSA) with 1 and 2 exhibited five times higher r1-relaxivities (11.3 and 22.0 mM-1 s-1 at 1.41 T, respectively).
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Affiliation(s)
- Thavasilingam Nagendraraj
- Bioinorganic Chemistry Laboratory/Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India
| | - S Senthil Kumaran
- Department of NMR, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India
| | - Ramasamy Mayilmurugan
- Bioinorganic Chemistry Laboratory/Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India.
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7
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Uzal-Varela R, Valencia L, Lalli D, Maneiro M, Esteban-Gómez D, Platas-Iglesias C, Botta M, Rodríguez-Rodríguez A. Understanding the Effect of the Electron Spin Relaxation on the Relaxivities of Mn(II) Complexes with Triazacyclononane Derivatives. Inorg Chem 2021; 60:15055-15068. [PMID: 34618439 PMCID: PMC8527457 DOI: 10.1021/acs.inorgchem.1c02057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Investigating the relaxation of water 1H nuclei induced by paramagnetic Mn(II) complexes is important to understand the mechanisms that control the efficiency of contrast agents used in diagnostic magnetic resonance imaging (MRI). Herein, a series of potentially hexadentate triazacyclononane (TACN) derivatives containing different pendant arms were designed to explore the relaxation of the electron spin in the corresponding Mn(II) complexes by using a combination of 1H NMR relaxometry and theoretical calculations. These ligands include 1,4,7-triazacyclononane-1,4,7-triacetic acid (H3NOTA) and three derivatives in which an acetate group is replaced by sulfonamide (H3NO2ASAm), amide (H2NO2AM), or pyridyl (H2NO2APy) pendants. The analogue of H3NOTA containing three propionate pendant arms (H3NOTPrA) was also investigated. The X-ray structure of the derivative containing two acetate groups and a sulfonamide pendant arm [Mn(NO2ASAm)]- evidenced six-coordination of the ligand to the metal ion, with the coordination polyhedron being close to a trigonal prism. The relaxivities of all complexes at 20 MHz and 25 °C (1.1-1.3 mM-1 s-1) are typical of systems that lack water molecules coordinated to the metal ion. The nuclear magnetic relaxation profiles evidence significant differences in the relaxivities of the complexes at low fields (<1 MHz), which are associated with different spin relaxation rates. The zero field splitting (ZFS) parameters calculated by using DFT and CASSCF methods show that electronic relaxation is relatively insensitive to the nature of the donor atoms. However, the twist angle of the two tripodal faces that delineate the coordination polyhedron, defined by the N atoms of the TACN unit (lower face) and the donor atoms of the pendant arms (upper face), has an important effect in the ZFS parameters. A twist angle close to the ideal value for an octahedral coordination (60°), such as that in [Mn(NOTPrA)]-, leads to a small ZFS energy, whereas this value increases as the coordination polyhedron approaches to a trigonal prism.
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Affiliation(s)
- Rocío Uzal-Varela
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071, A Coruña, Galicia, Spain
| | - Laura Valencia
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo, As Lagoas, Marcosende, 36310 Pontevedra, Spain
| | - Daniela Lalli
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro", Viale T. Michel 11, 15121 Alessandria, Italy
| | - Marcelino Maneiro
- Departamento de Química Inorgánica, Universidade de Santiago de Compostela, Facultade de Ciencias, Campus de Lugo, 27002 Lugo, Galicia, Spain
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071, A Coruña, Galicia, Spain
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071, A Coruña, Galicia, Spain
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro", Viale T. Michel 11, 15121 Alessandria, Italy
| | - Aurora Rodríguez-Rodríguez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071, A Coruña, Galicia, Spain
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8
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Guillou A, Galland M, Roux A, Váradi B, Gogolák RA, Le Saëc P, Faivre-Chauvet A, Beyler M, Bucher C, Tircsó G, Patinec V, Maury O, Tripier R. Picolinate-appended tacn complexes for bimodal imaging: Radiolabeling, relaxivity, photophysical and electrochemical studies. J Inorg Biochem 2020; 205:110978. [PMID: 31951911 DOI: 10.1016/j.jinorgbio.2019.110978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/11/2019] [Accepted: 12/24/2019] [Indexed: 10/25/2022]
Abstract
Based on our previous works involving two 1,4,7-triazacyclononane (tacn)-based ligands Hno2py1pa (1-Picolinic acid-4,7-bis(pyridin-2-ylmethyl)-1,4,7-triazacyclononane) and Hno1pa (1-Picolinic acid-1,4,7-triazacyclononane), we report here the synthesis of analogues bearing picolinate-based π-conjugated ILCT (Intra-Ligand Charge Transfer) transition antenna (HL1, HL2), using regiospecific N-functionalization of the tacn skeleton and their related transition metal complexes (e.g. Cu2+, Zn2+ and Mn2+). Coordination properties as well as their photophysical and electrochemical properties were investigated in order to quantify the impact of such antenna on the luminescent or relaxometric properties of the complexes. The spectroscopic properties of the targeted ligands and metal complexes have been studied using UV-Vis absorption and fluorescence spectrocopies. While the zinc complex formed with HL1 possesses a moderate quantum yield of 5%, complexation of Cu2+ led to an extinction of the luminescence putatively attributed to a photo-induced electron transfer, as supported by spectroscopic and electrochemical evidences. The [Mn(L2)]+ complex is characterized by a fluorescence quantum yield close to 8% in CH2Cl2. The potential interest of such systems as bimodal probes has been assessed from radiolabeling experiments conducted on HL1 and 64Cu2+ as well as confocal microscopy analyses and from relaxometric studies carried out on the cationic [Mn(L2)]+ complex. These results showed that HL1 can be used for radiolabeling, with a radiochemical conversion of 40% in 15 min at 100 °C. Finally, the relaxivity values obtained for [Mn(L2)]+, r1p = 4.80 mM-1·s-1 and r2p = 8.72 mM-1·s-1, make the Mn(II) complex an ideal candidate as a probe for Magnetic Resonance Imaging.
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Affiliation(s)
- Amaury Guillou
- Univ Brest, UMR-CNRS 6521 CEMCA, 6 avenue Victor le Gorgeu, 29200 Brest, France
| | - Margaux Galland
- Univ Lyon, ENS Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie, UMR 5182, 46 allée d'Italie, 69364 Lyon, France
| | - Amandine Roux
- Univ Lyon, ENS Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie, UMR 5182, 46 allée d'Italie, 69364 Lyon, France
| | - Balázs Váradi
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Réka Anna Gogolák
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Patricia Le Saëc
- Université de Nantes, Centre de Recherche en Cancérologie et Immunologie Nantes Angers (CRCINA), Unité INSERM 1232 - CNRS 6299, 8 quai Moncousu, BP 70721, 44007 Nantes Cedex, France
| | - Alain Faivre-Chauvet
- Université de Nantes, Centre de Recherche en Cancérologie et Immunologie Nantes Angers (CRCINA), Unité INSERM 1232 - CNRS 6299, 8 quai Moncousu, BP 70721, 44007 Nantes Cedex, France
| | - Maryline Beyler
- Univ Brest, UMR-CNRS 6521 CEMCA, 6 avenue Victor le Gorgeu, 29200 Brest, France
| | - Christophe Bucher
- Univ Lyon, ENS Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie, UMR 5182, 46 allée d'Italie, 69364 Lyon, France
| | - Gyula Tircsó
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Véronique Patinec
- Univ Brest, UMR-CNRS 6521 CEMCA, 6 avenue Victor le Gorgeu, 29200 Brest, France.
| | - Olivier Maury
- Univ Lyon, ENS Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie, UMR 5182, 46 allée d'Italie, 69364 Lyon, France.
| | - Raphaël Tripier
- Univ Brest, UMR-CNRS 6521 CEMCA, 6 avenue Victor le Gorgeu, 29200 Brest, France.
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Becatti M, Bencini A, Nistri S, Conti L, Fabbrini MG, Lucarini L, Ghini V, Severi M, Fiorillo C, Giorgi C, Sorace L, Valtancoli B, Bani D. Different Antioxidant Efficacy of Two Mn II-Containing Superoxide Anion Scavengers on Hypoxia/Reoxygenation-Exposed Cardiac Muscle Cells. Sci Rep 2019; 9:10320. [PMID: 31311943 PMCID: PMC6635543 DOI: 10.1038/s41598-019-46476-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/28/2019] [Indexed: 01/02/2023] Open
Abstract
Oxidative stress due to excess superoxide anion (\documentclass[12pt]{minimal}
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\begin{document}$${{\bf{O}}}_{{\bf{2}}}^{{\boldsymbol{\cdot }}{\boldsymbol{-}}}$$\end{document}O2⋅−-scavenging MnII complex with a new polyamino-polycarboxylate macrocycle (4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diacetate) containing 2 quinoline units (MnQ2), designed to improve complex stability and cell permeability, was compared to parental MnII complex with methyls replacing quinolines (MnM2). MnQ2 was more stable than MnM2 (log K = 19.56(8) vs. 14.73(2) for the equilibrium Mn2+ + L2−, where L = Q2 and M2) due to the involvement of quinoline in metal binding and to the hydrophobic features of the ligand which improve metal desolvation upon complexation. As oxidative stress model, H9c2 rat cardiomyoblasts were subjected to hypoxia-reoxygenation. MnQ2 and MnM2 (10 μmol L−1) were added at reoxygenation for 1 or 2 h. The more lipophilic MnQ2 showed more rapid cell and mitochondrial penetration than MnM2. Both MnQ2 and MnM2 abated endogenous ROS and mitochondrial \documentclass[12pt]{minimal}
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\begin{document}$${{\bf{O}}}_{{\bf{2}}}^{{\boldsymbol{\cdot }}{\boldsymbol{-}}}$$\end{document}O2⋅−, decreased cell lipid peroxidation, reduced mitochondrial dysfunction, in terms of efficiency of the respiratory chain and preservation of membrane potential (Δψ) and permeability, decreased the activation of pro-apoptotic caspases 9 and 3, and increased cell viability. Of note, MnQ2 was more effective than MnM2 to exert cytoprotective anti-oxidant effects in the short term. Compounds with redox-inert ZnII replacing the functional MnII were ineffective. This study provides clues which further our understanding of the structure-activity relationships of MnII-chelates and suggests that MnII-polyamino-polycarboxylate macrocycles could be developed as new anti-oxidant drugs.
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Affiliation(s)
- Matteo Becatti
- Department of, Experimental & Clinical Biomedical Sciences "Mario Serio", Section of Biochemical Sciences, University of Florence, viale G.B. Morgagni 50, 50134, Florence, Italy
| | - Andrea Bencini
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy.
| | - Silvia Nistri
- Department of Experimental & Clinical Medicine, Research Unit of Histology & Embryology, University of Florence, viale G. Pieraccini 6, 50139, Florence, Italy
| | - Luca Conti
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Maria Giulia Fabbrini
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Laura Lucarini
- Department NEUROFARBA, Section of Pharmacology, University of Florence, viale G. Pieraccini 6, 50139, Florence, Italy
| | - Veronica Ghini
- Center of Magnetic Resonance (CERM), University of Florence, Sesto Fiorentino, Florence, Italy
| | - Mirko Severi
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Claudia Fiorillo
- Department of, Experimental & Clinical Biomedical Sciences "Mario Serio", Section of Biochemical Sciences, University of Florence, viale G.B. Morgagni 50, 50134, Florence, Italy
| | - Claudia Giorgi
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Lorenzo Sorace
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Barbara Valtancoli
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Daniele Bani
- Department of Experimental & Clinical Medicine, Research Unit of Histology & Embryology, University of Florence, viale G. Pieraccini 6, 50139, Florence, Italy.
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Wissler HL, Ehlerding EB, Lyu Z, Zhao Y, Zhang S, Eshraghi A, Buuh ZY, McGuth JC, Guan Y, Engle JW, Bartlett SJ, Voelz VA, Cai W, Wang RE. Site-Specific Immuno-PET Tracer to Image PD-L1. Mol Pharm 2019; 16:2028-2036. [PMID: 30875232 DOI: 10.1021/acs.molpharmaceut.9b00010] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The rapid ascension of immune checkpoint blockade treatments has placed an emphasis on the need for viable, robust, and noninvasive imaging methods for immune checkpoint proteins, which could be of diagnostic value. Immunoconjugate-based positron emission tomography (immuno-PET) allows for sensitive and quantitative imaging of target levels and has promising potential for the noninvasive evaluation of immune checkpoint proteins. However, the advancement of immuno-PET is currently limited by available imaging tools, which heavily rely on full-length IgGs with Fc-mediated effects and are heterogeneous mixtures upon random conjugation with chelators for imaging. Herein, we have developed a site-specific αPD-L1 Fab conjugate with the chelator 1,4,7-triazacyclononane- N, N', N″-triacetic acid (NOTA), enabling radiolabeling for PET imaging, using the amber suppression-mediated genetic incorporation of unnatural amino acid (UAA), p-azidophenylalanine. This Fab conjugate is homogeneous and demonstrated tight binding toward the PD-L1 antigen in vitro. The radiolabeled version, 64Cu-NOTA-αPD-L1, has been employed in PET imaging to allow for effective visualization and mapping of the biodistribution of PD-L1 in two normal mouse models, including the capturing of different PD-L1 expression levels in the spleens of the different mouse types. Follow-up in vivo blocking studies and ex vivo fluorescent staining further validated specific tissue uptakes of the imaging agent. This approach illustrates the utility of UAA-based site-specific Fab conjugation as a general strategy for making sensitive PET imaging probes, which could facilitate the elucidation of the roles of a wide variety of immune checkpoint proteins in immunotherapy.
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Affiliation(s)
- Haley L Wissler
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Emily B Ehlerding
- Departments of Radiology and Medical Physics , University of Wisconsin-Madison , Madison , Wisconsin 53705 , United States
| | - Zhigang Lyu
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Yue Zhao
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Si Zhang
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Anisa Eshraghi
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Zakey Yusuf Buuh
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Jeffrey C McGuth
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Yifu Guan
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Jonathan W Engle
- Departments of Radiology and Medical Physics , University of Wisconsin-Madison , Madison , Wisconsin 53705 , United States
| | - Sarah J Bartlett
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Vincent A Voelz
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Weibo Cai
- Departments of Radiology and Medical Physics , University of Wisconsin-Madison , Madison , Wisconsin 53705 , United States
| | - Rongsheng E Wang
- Department of Chemistry , Temple University , 1901 N. 13th Street , Philadelphia , Pennsylvania 19122 , United States
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Pujales-Paradela R, Carniato F, Esteban-Gómez D, Botta M, Platas-Iglesias C. Controlling water exchange rates in potential Mn 2+-based MRI agents derived from NO2A 2. Dalton Trans 2019; 48:3962-3972. [PMID: 30834411 DOI: 10.1039/c9dt00211a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report a series of pentadentate ligands based on a 1,4,7-triazacyclononane-1,4-diacetic acid (H2NO2A) containing different substituents attached to the third nitrogen atom of the macrocyclic unit. Detailed 1H Nuclear Magnetic Relaxation Dispersion (NMRD) characterisation of the corresponding Mn2+ complexes suggests the formation of six-coordinate species in solution containing an inner-sphere water molecule. This was confirmed by recording the transverse 17O relaxation time and chemical shift measurements. The water exchange rate of the coordinated water molecule was found to be strongly influenced by the nature of the substituent R at position 7 of the triazacyclononane unit (R = Me, k298ex = 62.6 × 107 s-1; R = Bz, k298ex = 4.4 × 107 s-1; R = 1-phenylethyl, k298ex = 2.6 × 107 s-1). The decreasing exchange rates are explained by the increasing bulkiness of the substituent, which hinders the approach of the entering water molecule in an associatively activated water exchange mechanism. This is supported by DFT calculations (M062X/TZVP), which confirm the associative nature of the water exchange reaction. A potentially decadentate ligand containing two NO2A units linked by a xylenyl spacer in the meta position was also synthesised. The corresponding binuclear Mn2+ complex contains two metal ions with different hydration numbers, as evidenced by 1H NMRD and 17O NMR measurements. DFT calculations show that this is related to the presence of a bridging bidentate μ-η1-carboxylate group connecting the two metal centers. The results reported in this work provide a straightforward strategy to control the exchange rate of the coordinated water molecule in this family of MRI contrast agent candidates.
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Affiliation(s)
- Rosa Pujales-Paradela
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain.
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Wahsner J, Gale EM, Rodríguez-Rodríguez A, Caravan P. Chemistry of MRI Contrast Agents: Current Challenges and New Frontiers. Chem Rev 2019; 119:957-1057. [PMID: 30350585 PMCID: PMC6516866 DOI: 10.1021/acs.chemrev.8b00363] [Citation(s) in RCA: 832] [Impact Index Per Article: 166.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Tens of millions of contrast-enhanced magnetic resonance imaging (MRI) exams are performed annually around the world. The contrast agents, which improve diagnostic accuracy, are almost exclusively small, hydrophilic gadolinium(III) based chelates. In recent years concerns have arisen surrounding the long-term safety of these compounds, and this has spurred research into alternatives. There has also been a push to develop new molecularly targeted contrast agents or agents that can sense pathological changes in the local environment. This comprehensive review describes the state of the art of clinically approved contrast agents, their mechanism of action, and factors influencing their safety. From there we describe different mechanisms of generating MR image contrast such as relaxation, chemical exchange saturation transfer, and direct detection and the types of molecules that are effective for these purposes. Next we describe efforts to make safer contrast agents either by increasing relaxivity, increasing resistance to metal ion release, or by moving to gadolinium(III)-free alternatives. Finally we survey approaches to make contrast agents more specific for pathology either by direct biochemical targeting or by the design of responsive or activatable contrast agents.
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Affiliation(s)
- Jessica Wahsner
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Eric M. Gale
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Aurora Rodríguez-Rodríguez
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Peter Caravan
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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Pujales-Paradela R, Carniato F, Uzal-Varela R, Brandariz I, Iglesias E, Platas-Iglesias C, Botta M, Esteban-Gómez D. A pentadentate member of the picolinate family for Mn(ii) complexation and an amphiphilic derivative. Dalton Trans 2019; 48:696-710. [PMID: 30547165 DOI: 10.1039/c8dt03856b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report a pentadentate ligand containing a 2,2'-azanediyldiacetic acid moiety functionalized with a picolinate group at the nitrogen atom (H3paada), as well as a lipophylic derivative functionalized with a dodecyloxy group at position 4 of the pyridyl ring (H3C12Opaada). The protonation constants of the paada3- ligand and the stability constant of the Mn(ii) complex were determined using a combination of potentiometric and spectrophotometric titrations (25 °C, 0.15 M NaCl). A detailed relaxometric characterisation was accomplished by recording 1H Nuclear Magnetic Relaxation Dispersion (NMRD) profiles and 17O chemical shifts and relaxation rates. These studies provide detailed information on the microscopic parameters that control their efficiency as relaxation agents in vitro. For the sake of completeness and to facilitate comparison, we also characterised the related [Mn(nta)]- complex (nta = nitrilotriacetate). Both the [Mn(paada)]- and [Mn(nta)]- complexes turned out to contain two inner-sphere water molecules in aqueous solution. The exchange rate of these coordinated water molecules was slower in [Mn(paada)]- (k298ex = 90 × 107 s-1) than in [Mn(nta)]- (k298ex = 280 × 107 s-1). The complexes were also characterised using both DFT (TPSSh/def2-TZVP) and ab initio CAS(5,5) calculations. The lipophylic [Mn(C12Opaada)]- complex forms micelles in solution characterised by a critical micellar concentration (cmc) of 0.31 ± 0.01 mM. This complex also forms a rather strong adduct with Bovine Serum Albumin (BSA) with an association constant of 5.5 × 104 M-1 at 25 °C. The enthalpy and entropy changes obtained for the formation of the adduct indicate that the binding event is driven by hydrophobic interactions.
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Affiliation(s)
- Rosa Pujales-Paradela
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain.
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Ray S, Li Z, Hsu CH, Hwang LP, Lin YC, Chou PT, Lin YY. Dendrimer- and copolymer-based nanoparticles for magnetic resonance cancer theranostics. Theranostics 2018; 8:6322-6349. [PMID: 30613300 PMCID: PMC6299700 DOI: 10.7150/thno.27828] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/20/2018] [Indexed: 01/06/2023] Open
Abstract
Cancer theranostics is one of the most important approaches for detecting and treating patients at an early stage. To develop such a technique, accurate detection, specific targeting, and controlled delivery are the key components. Various kinds of nanoparticles have been proposed and demonstrated as potential nanovehicles for cancer theranostics. Among them, polymer-like dendrimers and copolymer-based core-shell nanoparticles could potentially be the best possible choices. At present, magnetic resonance imaging (MRI) is widely used for clinical purposes and is generally considered the most convenient and noninvasive imaging modality. Superparamagnetic iron oxide (SPIO) and gadolinium (Gd)-based dendrimers are the major nanostructures that are currently being investigated as nanovehicles for cancer theranostics using MRI. These structures are capable of specific targeting of tumors as well as controlled drug or gene delivery to tumor sites using pH, temperature, or alternating magnetic field (AMF)-controlled mechanisms. Recently, Gd-based pseudo-porous polymer-dendrimer supramolecular nanoparticles have shown 4-fold higher T1 relaxivity along with highly efficient AMF-guided drug release properties. Core-shell copolymer-based nanovehicles are an equally attractive alternative for designing contrast agents and for delivering anti-cancer drugs. Various copolymer materials could be used as core and shell components to provide biostability, modifiable surface properties, and even adjustable imaging contrast enhancement. Recent advances and challenges in MRI cancer theranostics using dendrimer- and copolymer-based nanovehicles have been summarized in this review article, along with new unpublished research results from our laboratories.
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Affiliation(s)
- Sayoni Ray
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Zhao Li
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Chao-Hsiung Hsu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Lian-Pin Hwang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Ying-Chih Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yung-Ya Lin
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
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Forgács A, Tei L, Baranyai Z, Esteban-Gómez D, Platas-Iglesias C, Botta M. Optimising the relaxivities of Mn 2+ complexes by targeting human serum albumin (HSA). Dalton Trans 2018. [PMID: 28632276 DOI: 10.1039/c7dt01508a] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We report two novel macrocyclic ligands based on the 1,4-DO2AM platform (1,4-DO2AM = 2,2'-(1,4,7,10-tetraazacyclododecane-1,4-diyl)diacetamide) and containing two benzyl groups attached either to the nitrogen atoms of the macrocyclic unit (1,4-BzDO2AM) or to the amide pendant arms (1,4-DO2AMBz). The protonation constants of the ligands and the stability constants of their Mn2+ complexes were determined using pH potentiometry. The introduction of benzyl groups results in a slight decrease of the stability constants of the Mn2+ complexes and a slight increase of their acid-catalysed dissociation reactions. A detailed relaxometric characterisation of the complexes using nuclear magnetic dispersion relaxation (NMRD) and 17O NMR studies indicated that the increase in molecular weight associated with the presence of benzyl groups results in a remarkable increase of proton relaxivities r1p, which take values of 3.8, 3.5 and 2.5 mM-1 s-1 for [Mn(1,4-BzDO2AM)]2+, [Mn(1,4-DO2AMBz)]2+ and [Mn(1,4-DO2AM)]2+ (at 25 °C and 20 MHz). The [Mn(1,4-BzDO2AM)]2+ and [Mn(1,4-DO2AMBz)]2+ complexes form relatively strong adducts with Human Serum Albumin (HSA) with association constants of (3.9 ± 0.6) × 103 and (2.0 ± 0.3) × 103 M-1, respectively. The interaction with the protein slows down the rotational tumbling of the complex in solution, which results in adducts endowed with remarkably high proton relaxivities (r1pb = 18.5 ± 0.7 and 27.4 ± 1.4 mM-1 s-1 for [Mn(1,4-BzDO2AM)]2+ and [Mn(1,4-DO2AMBz)]2+, respectively).
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Affiliation(s)
- Attila Forgács
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro", Viale T. Michel 11, 15121 Alessandria, Italy.
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Brewer SM, Palacios PM, Johnston HM, Pierce BS, Green KN. Isolation and identification of the pre-catalyst in iron-catalyzed direct arylation of pyrrole with phenylboronic acid. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.03.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Forgács A, Pujales-Paradela R, Regueiro-Figueroa M, Valencia L, Esteban-Gómez D, Botta M, Platas-Iglesias C. Developing the family of picolinate ligands for Mn 2+ complexation. Dalton Trans 2018; 46:1546-1558. [PMID: 28091671 DOI: 10.1039/c6dt04442e] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have reported here a series of ligands containing pentadentate 6,6'-(azanediylbis(methylene))dipicolinic acid units that differ in the substituent present at the amine nitrogen atom (acetate: H3DPAAA; phenyl: H2DPAPhA; dodecyl: H2DPAC12A; 4-hexylphenyl: H2DPAC6PhA). The protonation constants of the hexadentate DPAAA3- and pentadentate DPAPhA2- ligands and the stability constants of their Mn2+ complexes were determined using pH-potentiometry (25 °C, 0.15 M NaCl). The mono-hydrated [Mn(DPAAA)]- complex (log KMnL = 13.19(5)) was found to be considerably more stable than the bis-hydrated [Mn(DPAPhA)] analogue (log KMnL = 9.55(1)). A detailed 1H and 17O NMR relaxometric study was carried out to determine the parameters that govern the proton relaxivities of these complexes. The [Mn(DPAC12A)] complex, which contains a dodecyl lipophilic chain, forms micelles in solution characterized by a critical micellar concentration (cmc) of 96(9) μM. The lipophilic [Mn(DPAC6PhA)] and [Mn(DPAC12A)] derivatives form rather strong adducts with Human Serum Albumin (HSA) with association constants of 7.1 ± 0.1 × 103 and 1.3 ± 0.4 × 105 M-1, respectively. The X-ray structure of the complex {K(H2O)4}{[Mn(DPAAA)(H2O)]}2 shows that the Mn2+ ion in [Mn(DPAAA)]- is coordinated to the six donor atoms of the ligand, a coordinated water molecule completing the pentagonal bipyramidal coordination environment.
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Affiliation(s)
- Attila Forgács
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro", Viale T. Michel 11, 15121 Alessandria, Italy.
| | - Rosa Pujales-Paradela
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain.
| | - Martín Regueiro-Figueroa
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain.
| | - Laura Valencia
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo, As Lagoas, Marcosende, 36310 Pontevedra, Spain
| | - David Esteban-Gómez
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain.
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "A. Avogadro", Viale T. Michel 11, 15121 Alessandria, Italy.
| | - Carlos Platas-Iglesias
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain.
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Pota K, Garda Z, Kálmán FK, Barriada JL, Esteban-Gómez D, Platas-Iglesias C, Tóth I, Brücher E, Tircsó G. Taking the next step toward inert Mn2+ complexes of open-chain ligands: the case of the rigid PhDTA ligand. NEW J CHEM 2018. [DOI: 10.1039/c8nj00121a] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Equilibrium, dissociation kinetics, relaxometric and electrochemical properties of the [Mn(PhDTA)]2− complex were investigated and the structure of the [Mn(PhDTA)]2− complex was studied by using DFT calculations.
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Affiliation(s)
- Kristof Pota
- Department of Inorganic and Analytical Chemistry
- Faculty of Science and Technology
- University of Debrecen
- H-4032 Debrecen
- Hungary
| | - Zoltán Garda
- Department of Inorganic and Analytical Chemistry
- Faculty of Science and Technology
- University of Debrecen
- H-4032 Debrecen
- Hungary
| | - Ferenc Krisztián Kálmán
- Department of Inorganic and Analytical Chemistry
- Faculty of Science and Technology
- University of Debrecen
- H-4032 Debrecen
- Hungary
| | - José Luis Barriada
- Centro de Investigaciones Científicas Avanzadas (CICA)
- Departamento de Química, Universidade da Coruña
- Spain
| | - David Esteban-Gómez
- Centro de Investigaciones Científicas Avanzadas (CICA)
- Departamento de Química, Universidade da Coruña
- Spain
| | - Carlos Platas-Iglesias
- Centro de Investigaciones Científicas Avanzadas (CICA)
- Departamento de Química, Universidade da Coruña
- Spain
| | - Imre Tóth
- Department of Inorganic and Analytical Chemistry
- Faculty of Science and Technology
- University of Debrecen
- H-4032 Debrecen
- Hungary
| | - Ernő Brücher
- Department of Inorganic and Analytical Chemistry
- Faculty of Science and Technology
- University of Debrecen
- H-4032 Debrecen
- Hungary
| | - Gyula Tircsó
- Department of Inorganic and Analytical Chemistry
- Faculty of Science and Technology
- University of Debrecen
- H-4032 Debrecen
- Hungary
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Rolla G, De Biasio V, Giovenzana GB, Botta M, Tei L. Supramolecular assemblies based on amphiphilic Mn2+-complexes as high relaxivity MRI probes. Dalton Trans 2018; 47:10660-10670. [DOI: 10.1039/c8dt01250d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The Mn2+ complexes of amphiphilic derivatives of EDTA and 1,4-DO2A ligands show a strong increase in relaxivity upon micellar aggregation and human serum albumin binding.
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Affiliation(s)
- Gabriele Rolla
- Dipartimento di Scienze e Innovazione Tecnologica
- Università del Piemonte Orientale “Amedeo Avogadro”
- I-15121 Alessandria
- Italy
| | - Valeria De Biasio
- Dipartimento di Scienze del Farmaco
- Università del Piemonte Orientale “A. Avogadro”
- I-28100 Novara
- Italy
| | - Giovanni B. Giovenzana
- Dipartimento di Scienze del Farmaco
- Università del Piemonte Orientale “A. Avogadro”
- I-28100 Novara
- Italy
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica
- Università del Piemonte Orientale “Amedeo Avogadro”
- I-15121 Alessandria
- Italy
| | - Lorenzo Tei
- Dipartimento di Scienze e Innovazione Tecnologica
- Università del Piemonte Orientale “Amedeo Avogadro”
- I-15121 Alessandria
- Italy
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Vanasschen C, Brandt M, Ermert J, Coenen HH. Radiolabelling with isotopic mixtures of (52g/55)Mn(II) as a straight route to stable manganese complexes for bimodal PET/MR imaging. Dalton Trans 2016; 45:1315-21. [PMID: 26685974 DOI: 10.1039/c5dt04270d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Radiolabelling using isotopic mixtures of (52g/55)Mn(ii) offers fast and easy access to new small molecule PET/MR tracers, composed of chemically identical reporting units. trans-1,2-Diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA) was radiolabelled with carrier-added (52g)Mn(ii) in >99% radiochemical yield, producing the first manganese-based bimodal PET/MR probe. The Mn-CDTA chelate was shown to be very stable to air oxidation and sufficiently inert to decomplexation in blood serum. These data sparked our interest in functionalized CDTA ligands for the design of optimized PET/MR tracers.
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Affiliation(s)
- Christian Vanasschen
- Institut für Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
| | - Marie Brandt
- Institut für Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
| | - Johannes Ermert
- Institut für Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
| | - Heinz H Coenen
- Institut für Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
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21
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Forgács A, Tei L, Baranyai Z, Tóth I, Zékány L, Botta M. A Bisamide Derivative of [Mn(1,4-DO2A)] - Solution Thermodynamic, Kinetic, and NMR Relaxometric Studies. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201501415] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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22
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Luo Y, Zhao L, Li X, Yang J, Guo L, Zhang G, Shen M, Zhao J, Shi X. The design of a multifunctional dendrimer-based nanoplatform for targeted dual mode SPECT/MR imaging of tumors. J Mater Chem B 2016; 4:7220-7225. [DOI: 10.1039/c6tb02190e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A multifunctional dendrimer-based nanoplatform labeled with 99mTc can be synthesized for targeted SPECT/MR dual mode imaging of tumors.
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Affiliation(s)
- Yu Luo
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
- P. R. China
| | - Lingzhou Zhao
- Department of Nuclear Medicine
- Shanghai General Hospital
- School of Medicine
- Shanghai Jiaotong University
- Shanghai 200080
| | - Xin Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
- P. R. China
| | - Jia Yang
- Department of Radiology
- Shanghai General Hospital, School of Medicine
- Shanghai Jiaotong University
- Shanghai 200080
- P. R. China
| | - Lilei Guo
- Department of Nuclear Medicine
- Shanghai General Hospital
- School of Medicine
- Shanghai Jiaotong University
- Shanghai 200080
| | - Guixiang Zhang
- Department of Radiology
- Shanghai General Hospital, School of Medicine
- Shanghai Jiaotong University
- Shanghai 200080
- P. R. China
| | - Mingwu Shen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
- P. R. China
| | - Jinhua Zhao
- Department of Nuclear Medicine
- Shanghai General Hospital
- School of Medicine
- Shanghai Jiaotong University
- Shanghai 200080
| | - Xiangyang Shi
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
- P. R. China
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23
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A Practical Route for the Preparation of 1,4,7-Triazacyclononanyl Diacetates with a Hydroxypyridinonate Pendant Arm. Molecules 2015; 20:19393-405. [PMID: 26512638 PMCID: PMC6332087 DOI: 10.3390/molecules201019393] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/16/2015] [Accepted: 10/16/2015] [Indexed: 12/31/2022] Open
Abstract
The preparation of triazamacrocyclic hydroxypyridinonate (HOPO-TACN) derivatives as potential chelators for metals in biomedical applications was reported. The synthesis is based on a convergent synthetic approach, in which the key intermediate di-tert-butyl-2,2′-(1,4,7-triazonane-1,4-diyl) diacetate was coupled with a hydroxypyridinonate pendant arm. The method is suitable for rapid syntheses of metal chelator HOPO-TACNs of biomedical interest.
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Zhu J, Gale EM, Atanasova I, Rietz TA, Caravan P. Hexameric Mn(II) dendrimer as MRI contrast agent. Chemistry 2014; 20:14507-13. [PMID: 25224391 PMCID: PMC4260332 DOI: 10.1002/chem.201403883] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Indexed: 12/30/2022]
Abstract
A Mn(II) chelating dendrimer was prepared as a contrast agent for MRI applications. The dendrimer comprises six tyrosine-derived [Mn(EDTA)(H2 O)](2-) moieties coupled to a cyclotriphosphazene core. Variable temperature (17) O NMR spectroscopy revealed a single water co-ligand per Mn(II) that undergoes fast water exchange (kex =(3.0±0.1)×10(8) s(-1) at 37 °C). The 37 °C per Mn(II) relaxivity ranged from 8.2 to 3.8 mM(-1) s(-1) from 0.47 to 11.7 T, and is sixfold higher on a per molecule basis. From this field dependence a rotational correlation time was estimated as 0.45(±0.02) ns. The imaging and pharmacokinetic properties of the dendrimer were compared to clinically used [Gd(DTPA)(H2 O)](2-) in mice at 4.7 T. On first pass, the higher per ion relaxivity of the dendrimer resulted in twofold greater blood signal than for [Gd(DTPA)(H2 O)](2-) . Blood clearance was fast and elimination occurred through both the renal and hepatobiliary routes. This Mn(II) containing dendrimer represents a potential alternative to Gd-based contrast agents, especially in patients with chronic kidney disease where the use of current Gd-based agents may be contraindicated.
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Affiliation(s)
- Jiang Zhu
- Athinoula A. Martinos Center for Biomedical Imaging, Deparment of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, Masachusetts, USA, 02141
- Sichuan Key Laboratory of Medical Imaging, North Sichuan Medical College
| | - Eric M. Gale
- Athinoula A. Martinos Center for Biomedical Imaging, Deparment of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, Masachusetts, USA, 02141
| | - Iliyana Atanasova
- Massachusetts Institue of Technology, Cambridge, Massachusetts, USA, 02141
| | - Tyson A. Rietz
- Athinoula A. Martinos Center for Biomedical Imaging, Deparment of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, Masachusetts, USA, 02141
| | - Peter Caravan
- Athinoula A. Martinos Center for Biomedical Imaging, Deparment of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, Masachusetts, USA, 02141
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25
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Gale EM, Mukherjee S, Liu C, Loving GS, Caravan P. Structure-redox-relaxivity relationships for redox responsive manganese-based magnetic resonance imaging probes. Inorg Chem 2014; 53:10748-61. [PMID: 25226090 PMCID: PMC4186673 DOI: 10.1021/ic502005u] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Indexed: 12/11/2022]
Abstract
A library of 10 Mn-containing complexes capable of switching reversibly between the Mn(II) and Mn(III) oxidation states was prepared and evaluated for potential usage as MRI reporters of tissue redox activity. We synthesized N-(2-hydroxybenzyl)-N,N',N'-ethylenediaminetriacetic acid (HBET) and N-(2-hydroxybenzyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetic acid (CyHBET) ligands functionalized (-H, -OMe, -NO2) at the 5-position of the aromatic ring. The Mn(II) complexes of all ligands and the Mn(III) complexes of the 5-H and 5-NO2 functionalized ligands were synthesized and isolated, but the Mn(III) complexes with the 5-OMe functionalized ligands were unstable. (1)H relaxivity of the 10 isolable complexes was measured at pH 7.4 and 37 °C, 1.4 T. Thermodynamic stability, pH-dependent complex speciation, hydration state, water exchange kinetics of the Mn(II) complexes, and pseudo-first order reduction kinetics of the Mn(III) complexes were studied using a combination of pH-potentiometry, UV-vis spectroscopy, and (1)H and (17)O NMR measurements. The effects of ligand structural and electronic modifications on the Mn(II/III) redox couple were studied by cyclic voltammetry. The Mn(II) complexes are potent relaxation agents as compared to the corresponding Mn(III) species with [Mn(II)(CyHBET)(H2O)](2-) exhibiting a 7.5-fold higher relaxivity (3.3 mM(-1) s(-1)) than the oxidized form (0.4 mM(-1) s(-1)). At pH 7.4, Mn(II) exists as a mixture of fully deprotonated (ML) and monoprotonated (HML) complexes and Mn(II) complex stability decreases as the ligands become more electron-releasing (pMn for 10 μM [Mn(II)(CyHBET-R')(H2O)](2-) decreases from 7.6 to 6.2 as R' goes from -NO2 to -OMe, respectively). HML speciation increases as the electron-releasing nature of the phenolato-O donor increases. The presence of a water coligand is maintained upon conversion from HML to ML, but the water exchange rate of ML is faster by up to 2 orders of magnitude (k(ex)(310) for H[Mn(II)(CyHBET)(H2O)](-) and [Mn(II)(CyHBET)(H2O)](2-) are 1.2 × 10(8) and 1.0 × 10(10) s(-1), respectively). The Mn(II/III) redox potential can be tuned over a range of 0.30 V (E(1/2) = 0.27-0.57 V) through electronic modifications to the 5-substituent of the aromatic ligand component. However, care must be taken in tuning the ligand electronics to avoid Mn(III)-ligand autoredox. Taken together, these results serve to establish criteria for optimizing Mn(III) versus Mn(II) relaxivity differentials, complex stability, and Mn(II/III) redox potential.
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Affiliation(s)
| | | | - Cynthia Liu
- The Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology,
Massachusetts General Hospital, Harvard
Medical School, 149 Thirteenth
Street, Suite 2301, Charlestown, Massachusetts 02129, United States
| | - Galen S. Loving
- The Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology,
Massachusetts General Hospital, Harvard
Medical School, 149 Thirteenth
Street, Suite 2301, Charlestown, Massachusetts 02129, United States
| | - Peter Caravan
- The Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology,
Massachusetts General Hospital, Harvard
Medical School, 149 Thirteenth
Street, Suite 2301, Charlestown, Massachusetts 02129, United States
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26
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Molnár E, Camus N, Patinec V, Rolla GA, Botta M, Tircsó G, Kálmán FK, Fodor T, Tripier R, Platas-Iglesias C. Picolinate-containing macrocyclic Mn2+ complexes as potential MRI contrast agents. Inorg Chem 2014; 53:5136-49. [PMID: 24773460 DOI: 10.1021/ic500231z] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We report the synthesis of the ligand Hnompa (6-((1,4,7-triazacyclononan-1-yl)methyl)picolinic acid) and a detailed characterization of the Mn(2+) complexes formed by this ligand and the related ligands Hdompa (6-((1,4,7,10-tetraazacyclododecan-1-yl)methyl)picolinic acid) and Htempa (6-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)picolinic acid). These ligands form thermodynamically stable complexes in aqueous solution with stability constants of logKMnL = 10.28(1) (nompa), 14.48(1) (dompa), and 12.53(1) (tempa). A detailed study of the dissociation kinetics of these Mn(2+) complexes indicates that the decomplexation reaction at about neutral pH occurs mainly following a spontaneous dissociation mechanism. The X-ray structure of [Mn2(nompa)2(H2O)2](ClO4)2 shows that the Mn(2+) ion is seven-coordinate in the solid state, being directly bound to five donor atoms of the ligand, the oxygen atom of a coordinated water molecule and an oxygen atom of a neighboring nompa(-) ligand acting as a bridging bidentate carboxylate group (μ-η(1)-carboxylate). Nuclear magnetic relaxation dispersion ((1)H NMRD) profiles and (17)O NMR chemical shifts and transverse relaxation rates of aqueous solutions of [Mn(nompa)](+) indicate that the Mn(2+) ion is six-coordinate in solution by the pentadentate ligand and one inner-sphere water molecule. The analysis of the (1)H NMRD and (17)O NMR data provides a very high water exchange rate of the inner-sphere water molecule (kex(298) = 2.8 × 10(9) s(-1)) and an unusually high value of the (17)O hyperfine coupling constant of the coordinated water molecule (AO/ℏ = 73.3 ± 0.6 rad s(-1)). DFT calculations performed on the [Mn(nompa)(H2O)](+)·2H2O system (TPSSh model) provide a AO/ℏ value in excellent agreement with the one obtained experimentally.
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Affiliation(s)
- Enikő Molnár
- Departamento de Química Fundamental, Facultade de Ciencias, Universidade da Coruña , Campus da Zapateira-Rúa da Fraga 10, 15008 A Coruña, Spain
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27
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Esteban-Gómez D, Cassino C, Botta M, Platas-Iglesias C. 17O and 1H relaxometric and DFT study of hyperfine coupling constants in [Mn(H2O)6]2+. RSC Adv 2014. [DOI: 10.1039/c3ra45721d] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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28
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Patinec V, Rolla GA, Botta M, Tripier R, Esteban-Gómez D, Platas-Iglesias C. Hyperfine coupling constants on inner-sphere water molecules of a triazacyclononane-based Mn(II) complex and related systems relevant as MRI contrast agents. Inorg Chem 2013; 52:11173-84. [PMID: 24070368 DOI: 10.1021/ic4014366] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report the synthesis of the ligand H2MeNO2A (1,4-bis(carboxymethyl)-7-methyl-1,4,7-triazacyclononane) and a detailed experimental and computational study of the hyperfine coupling constants (HFCCs) on the inner-sphere water molecules of [Mn(MeNO2A)] and related Mn(2+) complexes relevant as potential contrast agents in magnetic resonance imaging (MRI). Nuclear magnetic relaxation dispersion (NMRD) profiles, (17)O NMR chemical shifts, and transverse relaxation rates of aqueous solutions of [Mn(MeNO2A)] were recorded to determine the parameters governing the relaxivity in this complex and the (17)O and (1)H HFCCs. DFT calculations (TPSSh model) performed in aqueous solution (PCM model) on the [Mn(MeNO2A)(H2O)]·xH2O and [Mn(EDTA)(H2O)](2-)·xH2O (x = 0-4) systems were used to determine theoretically the (17)O and (1)H HFCCs responsible for the (17)O NMR chemical shifts and the scalar contributions to (17)O and (1)H NMR relaxation rates. The use of a mixed cluster/continuum approach with the explicit inclusion of a few second-sphere water molecules is critical for an accurate calculation of HFCCs of coordinated water molecules. The impact of complex dynamics on the calculated HFCCs was evaluated with the use of molecular dynamics simulations within the atom-centered density matrix propagation (ADMP) approach. The (17)O and (1)H HFCCs calculated for these complexes and related systems show an excellent agreement with the experimental data. Both the (1)H and (17)O HFCCs (A(iso) values) are dominated by the spin delocalization mechanism. The A(iso) values are significantly affected by the distance between the oxygen atom of the coordinated water molecule and the Mn(2+) ion, as well as by the orientation of the water molecule plane with respect to the Mn-O vector.
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Affiliation(s)
- Véronique Patinec
- Departamento de Química Fundamental, Facultade de Ciencias, Universidade da Coruña , Campus da Zapateira-Rúa da Fraga 10, 15008 A Coruña, Spain
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