2017
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Rhenium Complexes Based on 2-Pyridyl-1,2,3-triazole Ligands: A New Class of CO2 Reduction Catalysts Article de journal H Y V Ching; X Wang; M He; N Perujo Holland; R Guillot; C Slim; S Griveau; H C Bertrand; C Policar; F Bedioui; M Fontecave Inorganic Chemistry, 56 (5), p. 2966–2976, 2017. @article{Ching:2017,
title = {Rhenium Complexes Based on 2-Pyridyl-1,2,3-triazole Ligands: A New Class of CO2 Reduction Catalysts},
author = {H Y V Ching and X Wang and M He and N Perujo Holland and R Guillot and C Slim and S Griveau and H C Bertrand and C Policar and F Bedioui and M Fontecave},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014526293&doi=10.1021%2facs.inorgchem.6b03078&partnerID=40&md5=5aa6a6db21554e7bca56e0f1e1de9856},
doi = {10.1021/acs.inorgchem.6b03078},
year = {2017},
date = {2017-01-01},
journal = {Inorganic Chemistry},
volume = {56},
number = {5},
pages = {2966--2976},
abstract = {A series of [Re(NtextasciicircumN)(CO)3(X)] (NtextasciicircumN = diimine and X = halide) complexes based on 4-(2-pyridyl)-1,2,3-triazole (pyta) and 1-(2-pyridyl)-1,2,3-triazole (tapy) diimine ligands have been prepared and electrochemically characterized. The first ligand-based reduction process is shown to be highly sensitive to the nature of the isomer as well as to the substituents on the pyridyl ring, with the peak potential changing by up to 700 mV. The abilities of this class of complexes to catalyze the electroreduction and photoreduction of CO2 were assessed for the first time. It is found that only Re pyta complexes that have a first reduction wave with a peak potential at ca. −1.7 V vs SCE are active, producing CO as the major product, together with small amounts of H2 and formic acid. The catalytic wave that is observed in the CVs is enhanced by the addition of water or trifluoroethanol as a proton source. Long-term controlled potential electrolysis experiments gave total Faradaic yield close to 100%. In particular, functionalization of the triazolyl ring with a 2,4,6-tri-tert-butylphenyl group provided the catalyst with a remarkable stability. © 2017 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A series of [Re(NtextasciicircumN)(CO)3(X)] (NtextasciicircumN = diimine and X = halide) complexes based on 4-(2-pyridyl)-1,2,3-triazole (pyta) and 1-(2-pyridyl)-1,2,3-triazole (tapy) diimine ligands have been prepared and electrochemically characterized. The first ligand-based reduction process is shown to be highly sensitive to the nature of the isomer as well as to the substituents on the pyridyl ring, with the peak potential changing by up to 700 mV. The abilities of this class of complexes to catalyze the electroreduction and photoreduction of CO2 were assessed for the first time. It is found that only Re pyta complexes that have a first reduction wave with a peak potential at ca. −1.7 V vs SCE are active, producing CO as the major product, together with small amounts of H2 and formic acid. The catalytic wave that is observed in the CVs is enhanced by the addition of water or trifluoroethanol as a proton source. Long-term controlled potential electrolysis experiments gave total Faradaic yield close to 100%. In particular, functionalization of the triazolyl ring with a 2,4,6-tri-tert-butylphenyl group provided the catalyst with a remarkable stability. © 2017 American Chemical Society. |
A Cell-Penetrant Manganese Superoxide Dismutase (MnSOD) Mimic Is Able to Complement MnSOD and Exerts an Antiinflammatory Effect on Cellular and Animal Models of Inflammatory Bowel Diseases Article de journal E Mathieu; A -S Bernard; N Delsuc; E Quévrain; G Gazzah; B Lai; F Chain; P Langella; M Bachelet; J Masliah; P Seksik; C Policar Inorganic Chemistry, 56 (5), p. 2545–2555, 2017. @article{Mathieu:2017,
title = {A Cell-Penetrant Manganese Superoxide Dismutase (MnSOD) Mimic Is Able to Complement MnSOD and Exerts an Antiinflammatory Effect on Cellular and Animal Models of Inflammatory Bowel Diseases},
author = {E Mathieu and A -S Bernard and N Delsuc and E Qu\'{e}vrain and G Gazzah and B Lai and F Chain and P Langella and M Bachelet and J Masliah and P Seksik and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014763334&doi=10.1021%2facs.inorgchem.6b02695&partnerID=40&md5=acd51065ea36d5da707ec8c1915634a0},
doi = {10.1021/acs.inorgchem.6b02695},
year = {2017},
date = {2017-01-01},
journal = {Inorganic Chemistry},
volume = {56},
number = {5},
pages = {2545--2555},
abstract = {Inorganic complexes are increasingly used for biological and medicinal applications, and the question of the cell penetration and distribution of metallodrugs is key to understanding their biological activity. Oxidative stress is known to be involved in inflammation and in inflammatory bowel diseases for which antioxidative defenses are weakened. We report here the study of the manganese complex Mn1 mimicking superoxide dismutase (SOD), a protein involved in cell protection against oxidative stress, using an approach in inorganic cellular chemistry combining the investigation of Mn1 intracellular speciation using mass spectrometry and of its quantification and distribution using electron paramagnetic resonance and spatially resolved X-ray fluorescence with evaluation of its biological activity. More precisely, we have looked for and found the MS signature of Mn1 in cell lysates and quantified the overall manganese content. Intestinal epithelial cells activated by bacterial lipopolysaccharide were taken as a cellular model of oxidative stress and inflammation. DNBS-induced colitis in mice was used to investigate Mn1 activity in vivo. Mn1 exerts an intracellular antiinflammatory activity, remains at least partially coordinated, with diffuse distribution over the whole cell, and functionally complements mitochondrial MnSOD. © 2017 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Inorganic complexes are increasingly used for biological and medicinal applications, and the question of the cell penetration and distribution of metallodrugs is key to understanding their biological activity. Oxidative stress is known to be involved in inflammation and in inflammatory bowel diseases for which antioxidative defenses are weakened. We report here the study of the manganese complex Mn1 mimicking superoxide dismutase (SOD), a protein involved in cell protection against oxidative stress, using an approach in inorganic cellular chemistry combining the investigation of Mn1 intracellular speciation using mass spectrometry and of its quantification and distribution using electron paramagnetic resonance and spatially resolved X-ray fluorescence with evaluation of its biological activity. More precisely, we have looked for and found the MS signature of Mn1 in cell lysates and quantified the overall manganese content. Intestinal epithelial cells activated by bacterial lipopolysaccharide were taken as a cellular model of oxidative stress and inflammation. DNBS-induced colitis in mice was used to investigate Mn1 activity in vivo. Mn1 exerts an intracellular antiinflammatory activity, remains at least partially coordinated, with diffuse distribution over the whole cell, and functionally complements mitochondrial MnSOD. © 2017 American Chemical Society. |
Re(I) carbonyl complexes: Multimodal platforms for inorganic chemical biology Article de journal S Hostachy; C Policar; N Delsuc Coordination Chemistry Reviews, 351 , p. 172–188, 2017. @article{Hostachy:2017,
title = {Re(I) carbonyl complexes: Multimodal platforms for inorganic chemical biology},
author = {S Hostachy and C Policar and N Delsuc},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020033654&doi=10.1016%2fj.ccr.2017.05.004&partnerID=40&md5=ea1241c6f9199448b3fbb2bfc259b363},
doi = {10.1016/j.ccr.2017.05.004},
year = {2017},
date = {2017-01-01},
journal = {Coordination Chemistry Reviews},
volume = {351},
pages = {172--188},
abstract = {Bio-imaging, by enabling the visualization of biomolecules of interest, has proved to be highly informative in the study of biological processes. Although fluorescence microscopy is probably one of the most used techniques, alternative methods of imaging, providing complementary information, are emerging. In this context, metal complexes represent valuable platforms for multimodal imaging, since they may combine interesting spectroscopic features and biologically relevant functionalization on a single molecular core. In particular, d6 low-spin rhenium tri-carbonyl complexes display unique luminescence and vibrational properties, and can be readily functionalized. Here we review their applications and potential as probes or drugs relying on their photophysical properties, before focusing on their use as multimodal probes for the labelling and imaging of peptides and proteins. © 2017 Elsevier B.V.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Bio-imaging, by enabling the visualization of biomolecules of interest, has proved to be highly informative in the study of biological processes. Although fluorescence microscopy is probably one of the most used techniques, alternative methods of imaging, providing complementary information, are emerging. In this context, metal complexes represent valuable platforms for multimodal imaging, since they may combine interesting spectroscopic features and biologically relevant functionalization on a single molecular core. In particular, d6 low-spin rhenium tri-carbonyl complexes display unique luminescence and vibrational properties, and can be readily functionalized. Here we review their applications and potential as probes or drugs relying on their photophysical properties, before focusing on their use as multimodal probes for the labelling and imaging of peptides and proteins. © 2017 Elsevier B.V. |
2016
|
A Bis-Manganese(II)–DOTA Complex for Pulsed Dipolar Spectroscopy Article de journal P Demay-Drouhard; H Y V Ching; D Akhmetzyanov; R Guillot; L C Tabares; H C Bertrand; C Policar ChemPhysChem, p. 2066–2078, 2016. @article{Demay-Drouhard:2016,
title = {A Bis-Manganese(II)\textendashDOTA Complex for Pulsed Dipolar Spectroscopy},
author = {P Demay-Drouhard and H Y V Ching and D Akhmetzyanov and R Guillot and L C Tabares and H C Bertrand and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977597209&doi=10.1002%2fcphc.201600234&partnerID=40&md5=38a2466ad0f00d0edb158d200429986c},
doi = {10.1002/cphc.201600234},
year = {2016},
date = {2016-01-01},
journal = {ChemPhysChem},
pages = {2066--2078},
abstract = {High-spin gadolinium(III) and manganese(II) complexes have emerged as alternatives to standard nitroxide radical spin labels for measuring nanometric distances by using pulsed electron\textendashelectron double resonance (PELDOR or DEER) at high fields/frequencies. For certain complexes, particularly those with relatively small zero-field splitting (ZFS) and short distances between the two metal centers, the pseudosecular term of the dipolar coupling Hamiltonian is non-negligible. However, in general, the contribution from this term during conventional data analysis is masked by the flexibility of the molecule of interest and/or the long tethers connecting them to the spin labels. The efficient synthesis of a model system consisting of two [Mn(dota)]2− (MnDOTA; DOTA4−=1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) directly connected to the ends of a central rodlike oligo(phenylene\textendashethynylene) (OPE) spacer is reported. The rigidity of the OPE is confirmed by Q-band PELDOR measurements on a bis-nitroxide analogue. The MnII−MnII distance distribution profile determined by W-band PELDOR is in reasonable agreement with one simulated by using a simple rotamer analysis. The small degree of flexibility arising from the linking MnDOTA arm appears to outweigh the contribution from the pseudosecular term at this interspin distance. This study illustrates the potential of MnDOTA-based spin labels for measuring fairly short nanometer distances, and also presents an interesting candidate for in-depth studies of pulsed dipolar spectroscopy methods on MnII−MnII systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
High-spin gadolinium(III) and manganese(II) complexes have emerged as alternatives to standard nitroxide radical spin labels for measuring nanometric distances by using pulsed electron–electron double resonance (PELDOR or DEER) at high fields/frequencies. For certain complexes, particularly those with relatively small zero-field splitting (ZFS) and short distances between the two metal centers, the pseudosecular term of the dipolar coupling Hamiltonian is non-negligible. However, in general, the contribution from this term during conventional data analysis is masked by the flexibility of the molecule of interest and/or the long tethers connecting them to the spin labels. The efficient synthesis of a model system consisting of two [Mn(dota)]2− (MnDOTA; DOTA4−=1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) directly connected to the ends of a central rodlike oligo(phenylene–ethynylene) (OPE) spacer is reported. The rigidity of the OPE is confirmed by Q-band PELDOR measurements on a bis-nitroxide analogue. The MnII−MnII distance distribution profile determined by W-band PELDOR is in reasonable agreement with one simulated by using a simple rotamer analysis. The small degree of flexibility arising from the linking MnDOTA arm appears to outweigh the contribution from the pseudosecular term at this interspin distance. This study illustrates the potential of MnDOTA-based spin labels for measuring fairly short nanometer distances, and also presents an interesting candidate for in-depth studies of pulsed dipolar spectroscopy methods on MnII−MnII systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim |
The Use of Mn(II) Bound to His-tags as Genetically Encodable Spin-Label for Nanometric Distance Determination in Proteins Article de journal H Y V Ching; F C Mascali; H C Bertrand; E M Bruch; P Demay-Drouhard; R M Rasia; C Policar; L C Tabares; S Un Journal of Physical Chemistry Letters, 7 (6), p. 1072–1076, 2016. @article{Ching:2016,
title = {The Use of Mn(II) Bound to His-tags as Genetically Encodable Spin-Label for Nanometric Distance Determination in Proteins},
author = {H Y V Ching and F C Mascali and H C Bertrand and E M Bruch and P Demay-Drouhard and R M Rasia and C Policar and L C Tabares and S Un},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962539336&doi=10.1021%2facs.jpclett.6b00362&partnerID=40&md5=16161dac85830ffcae821a41e6480d4c},
doi = {10.1021/acs.jpclett.6b00362},
year = {2016},
date = {2016-01-01},
journal = {Journal of Physical Chemistry Letters},
volume = {7},
number = {6},
pages = {1072--1076},
abstract = {A genetically encodable paramagnetic spin-label capable of self-assembly from naturally available components would offer a means for studying the in-cell structure and interactions of a protein by electron paramagnetic resonance (EPR). Here, we demonstrate pulse electron-electron double resonance (DEER) measurements on spin-labels consisting of Mn(II) ions coordinated to a sequence of histidines, so-called His-tags, that are ubiquitously added by genetic engineering to facilitate protein purification. Although the affinity of His-tags for Mn(II) was low (800 μM), Mn(II)-bound His-tags yielded readily detectable DEER time traces even at concentrations expected in cells. We were able to determine accurately the distance between two His-tag Mn(II) spin-labels at the ends of a rigid helical polyproline peptide of known structure, as well as at the ends of a completely cell-synthesized 3-helix bundle. This approach not only greatly simplifies the labeling procedure but also represents a first step towards using self-assembling metal spin-labels for in-cell distance measurements. © 2016 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A genetically encodable paramagnetic spin-label capable of self-assembly from naturally available components would offer a means for studying the in-cell structure and interactions of a protein by electron paramagnetic resonance (EPR). Here, we demonstrate pulse electron-electron double resonance (DEER) measurements on spin-labels consisting of Mn(II) ions coordinated to a sequence of histidines, so-called His-tags, that are ubiquitously added by genetic engineering to facilitate protein purification. Although the affinity of His-tags for Mn(II) was low (800 μM), Mn(II)-bound His-tags yielded readily detectable DEER time traces even at concentrations expected in cells. We were able to determine accurately the distance between two His-tag Mn(II) spin-labels at the ends of a rigid helical polyproline peptide of known structure, as well as at the ends of a completely cell-synthesized 3-helix bundle. This approach not only greatly simplifies the labeling procedure but also represents a first step towards using self-assembling metal spin-labels for in-cell distance measurements. © 2016 American Chemical Society. |
RIDME spectroscopy on high-spin Mn2+ centers Article de journal D Akhmetzyanov; H Y V Ching; V Denysenkov; P Demay-Drouhard; H C Bertrand; L C Tabares; C Policar; T F Prisner; S Un Physical Chemistry Chemical Physics, 18 (44), p. 30857–30866, 2016. @article{Akhmetzyanov:2016,
title = {RIDME spectroscopy on high-spin Mn2+ centers},
author = {D Akhmetzyanov and H Y V Ching and V Denysenkov and P Demay-Drouhard and H C Bertrand and L C Tabares and C Policar and T F Prisner and S Un},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85025823502&doi=10.1039%2fc6cp05239h&partnerID=40&md5=d3a6cd609c88b382cf0297ed361d4003},
doi = {10.1039/c6cp05239h},
year = {2016},
date = {2016-01-01},
journal = {Physical Chemistry Chemical Physics},
volume = {18},
number = {44},
pages = {30857--30866},
abstract = {Pulsed EPR dipolar spectroscopy is a powerful tool for determining the structure and conformational dynamics of biological macromolecules, as it allows precise measurements of distances in the range of 1.5-10 nm. Utilization of high-spin Mn2+ species as spin probes for distance measurements is of significant interest, because they are biologically compatible and endogenous in numerous biological systems. However, to date dipolar spectroscopy experiments with this kind of species have been underexplored. Here we present pulsed electron electron double resonance (PELDOR also called DEER) and relaxation-induced dipolar modulation enhancement (RIDME) experiments, which have been performed at W-band (94 GHz) and J-band frequencies (263 GHz) on a bis-MnDOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) model system. The distances obtained from these experiments are in good agreement with predictions. RIDME experiments reveal a significantly higher modulation depth compared to PELDOR, which is an important consideration for biological samples. These experiments also feature higher harmonics of the dipolar coupling frequency due to effective multiple-quantum relaxation of high-spin Mn2+ as well as the multiple-component background function. Harmonics of the dipolar coupling frequency were taken into account by including additional terms in the kernel function of Tikhonov regularization analysis. © The Owner Societies 2016.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Pulsed EPR dipolar spectroscopy is a powerful tool for determining the structure and conformational dynamics of biological macromolecules, as it allows precise measurements of distances in the range of 1.5-10 nm. Utilization of high-spin Mn2+ species as spin probes for distance measurements is of significant interest, because they are biologically compatible and endogenous in numerous biological systems. However, to date dipolar spectroscopy experiments with this kind of species have been underexplored. Here we present pulsed electron electron double resonance (PELDOR also called DEER) and relaxation-induced dipolar modulation enhancement (RIDME) experiments, which have been performed at W-band (94 GHz) and J-band frequencies (263 GHz) on a bis-MnDOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) model system. The distances obtained from these experiments are in good agreement with predictions. RIDME experiments reveal a significantly higher modulation depth compared to PELDOR, which is an important consideration for biological samples. These experiments also feature higher harmonics of the dipolar coupling frequency due to effective multiple-quantum relaxation of high-spin Mn2+ as well as the multiple-component background function. Harmonics of the dipolar coupling frequency were taken into account by including additional terms in the kernel function of Tikhonov regularization analysis. © The Owner Societies 2016. |
Bimodal X-ray and Infrared Imaging of an Organometallic Derivative of Praziquantel in Schistosoma mansoni Article de journal S Clède; N Cowan; F Lambert; H C Bertrand; R Rubbiani; M Patra; J Hess; C Sandt; N Trcera; G Gasser; J Keiser; C Policar ChemBioChem, 17 (11), p. 1004–1007, 2016. @article{Clede:2016,
title = {Bimodal X-ray and Infrared Imaging of an Organometallic Derivative of Praziquantel in Schistosoma mansoni},
author = {S Cl\`{e}de and N Cowan and F Lambert and H C Bertrand and R Rubbiani and M Patra and J Hess and C Sandt and N Trcera and G Gasser and J Keiser and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973124415&doi=10.1002%2fcbic.201500688&partnerID=40&md5=608b1bb28a5237e0717a29ee815e73bc},
doi = {10.1002/cbic.201500688},
year = {2016},
date = {2016-01-01},
journal = {ChemBioChem},
volume = {17},
number = {11},
pages = {1004--1007},
abstract = {An organometallic derivative of praziquantel was studied directly in worms by using inductively coupled plasma-mass spectrometry (ICP-MS) for quantification and synchrotron-based imaging. X-ray fluorescence (XRF) and IR absorption spectromicroscopy were used for the first time in combination to directly locate this organometallic drug candidate in schistosomes. The detection of both CO (IR) and Cr (XRF) signatures proved that the Cr(CO)3 core remained intact in the worms. Images showed a preferential accumulation at the worm's tegument, consistent with a possible targeting of the calcium channel but not excluding other biological targets inside the worm. Imaginative imaging: Two synchrotron-based techniques - X-ray fluorescence and IR absorption spectroscopy - were used in combination for the first time to directly locate an organometallic drug candidate in schistosomes. This represents a novel approach to examine mechanisms of actions for organometallic compounds and might lead to the discovery of new drug candidates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An organometallic derivative of praziquantel was studied directly in worms by using inductively coupled plasma-mass spectrometry (ICP-MS) for quantification and synchrotron-based imaging. X-ray fluorescence (XRF) and IR absorption spectromicroscopy were used for the first time in combination to directly locate this organometallic drug candidate in schistosomes. The detection of both CO (IR) and Cr (XRF) signatures proved that the Cr(CO)3 core remained intact in the worms. Images showed a preferential accumulation at the worm's tegument, consistent with a possible targeting of the calcium channel but not excluding other biological targets inside the worm. Imaginative imaging: Two synchrotron-based techniques - X-ray fluorescence and IR absorption spectroscopy - were used in combination for the first time to directly locate an organometallic drug candidate in schistosomes. This represents a novel approach to examine mechanisms of actions for organometallic compounds and might lead to the discovery of new drug candidates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Bioinspired superoxide-dismutase mimics: The effects of functionalization with cationic polyarginine peptides Article de journal H Y V Ching; I Kenkel; N Delsuc; E Mathieu; I Ivanović-Burmazović; C Policar Journal of Inorganic Biochemistry, 160 , p. 172–179, 2016. @article{Ching:2016a,
title = {Bioinspired superoxide-dismutase mimics: The effects of functionalization with cationic polyarginine peptides},
author = {H Y V Ching and I Kenkel and N Delsuc and E Mathieu and I Ivanovi\'{c}-Burmazovi\'{c} and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964372716&doi=10.1016%2fj.jinorgbio.2016.01.025&partnerID=40&md5=035d0c2b5ffd4ee0b6fb74df285838da},
doi = {10.1016/j.jinorgbio.2016.01.025},
year = {2016},
date = {2016-01-01},
journal = {Journal of Inorganic Biochemistry},
volume = {160},
pages = {172--179},
abstract = {Continuing a bio-mimetic approach, we have prepared peptide conjugates of a superoxide dismutase (SOD) mimic [MnL]+ (where HL = N-(2-hydroxybenzyl)-N,N'-bis[2-(N-methylimidazolyl)methyl]ethane-1,2-diamine), namely [MnL'-Arg(n-1)]n+ (where n = 2, 4, 7 and 10) and [MnL'-Gly1]+. [MnL'-Arg(n-1)]n+ contained cationic residue(s) that emulate the electrostatic channel of the enzyme. Physicochemical methods showed that functionalization at the secondary amine of HL did not impair coordination to MnII with association constants (Kassoc) between 1.6 and 3.3 × 106 M- 1. The MnIII/MnII redox potential of the conjugates was between 0.27 and 0.30 V vs SCE, slightly higher than [MnL]+ under the same conditions, but remain at a value that facilitates O2•- dismutation. The catalytic rate constant (kcat) of the dismutation for the series was studied using a direct stopped-flow method, which showed that for compounds with the same overall charge, the alkylation of the secondary amine of [MnL]+ (kcat = 5.0 ± 0.1 × 106 M- 1 s- 1) led to a lower value (i.e. for [MnL'Gly]+},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Continuing a bio-mimetic approach, we have prepared peptide conjugates of a superoxide dismutase (SOD) mimic [MnL]+ (where HL = N-(2-hydroxybenzyl)-N,N'-bis[2-(N-methylimidazolyl)methyl]ethane-1,2-diamine), namely [MnL'-Arg(n-1)]n+ (where n = 2, 4, 7 and 10) and [MnL'-Gly1]+. [MnL'-Arg(n-1)]n+ contained cationic residue(s) that emulate the electrostatic channel of the enzyme. Physicochemical methods showed that functionalization at the secondary amine of HL did not impair coordination to MnII with association constants (Kassoc) between 1.6 and 3.3 × 106 M- 1. The MnIII/MnII redox potential of the conjugates was between 0.27 and 0.30 V vs SCE, slightly higher than [MnL]+ under the same conditions, but remain at a value that facilitates O2•- dismutation. The catalytic rate constant (kcat) of the dismutation for the series was studied using a direct stopped-flow method, which showed that for compounds with the same overall charge, the alkylation of the secondary amine of [MnL]+ (kcat = 5.0 ± 0.1 × 106 M- 1 s- 1) led to a lower value (i.e. for [MnL'Gly]+ |
Photophysical properties of single core multimodal probe for imaging (SCoMPI) in a membrane model and in cells Article de journal S Hostachy; J -M Swiecicki; C Sandt; N Delsuc; C Policar Dalton Transactions, 45 (7), p. 2791–2795, 2016. @article{Hostachy:2016,
title = {Photophysical properties of single core multimodal probe for imaging (SCoMPI) in a membrane model and in cells},
author = {S Hostachy and J -M Swiecicki and C Sandt and N Delsuc and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958064177&doi=10.1039%2fc5dt03819g&partnerID=40&md5=fb027086e6424b54b23cc2c11098e273},
doi = {10.1039/c5dt03819g},
year = {2016},
date = {2016-01-01},
journal = {Dalton Transactions},
volume = {45},
number = {7},
pages = {2791--2795},
abstract = {The spectroscopic properties of two luminescent Re(i) tricarbonyl complexes conjugated with two cell-penetrating peptides were examined. Fluorescence experiments and IR quantification in membrane models and in cells showed unexpectedly strong luminescence enhancement for one of the complexes in a lipid environment. © The Royal Society of Chemistry 2016.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The spectroscopic properties of two luminescent Re(i) tricarbonyl complexes conjugated with two cell-penetrating peptides were examined. Fluorescence experiments and IR quantification in membrane models and in cells showed unexpectedly strong luminescence enhancement for one of the complexes in a lipid environment. © The Royal Society of Chemistry 2016. |
New insight into the structural, electrochemical and biological aspects of macroacyclic Cu(II) complexes derived from S-substituted dithiocarbazate schiff bases Article de journal M L Low; L Maigre; M I M Tahir; E R T Tiekink; P Dorlet; R Guillot; T B Ravoof; R Rosli; J -M Pagès; C Policar; N Delsuc; K A Crouse European Journal of Medicinal Chemistry, 120 , p. 1–12, 2016. @article{Low:2016,
title = {New insight into the structural, electrochemical and biological aspects of macroacyclic Cu(II) complexes derived from S-substituted dithiocarbazate schiff bases},
author = {M L Low and L Maigre and M I M Tahir and E R T Tiekink and P Dorlet and R Guillot and T B Ravoof and R Rosli and J -M Pag\`{e}s and C Policar and N Delsuc and K A Crouse},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84967102584&doi=10.1016%2fj.ejmech.2016.04.027&partnerID=40&md5=71cde180942655ac9c57205e82887fcf},
doi = {10.1016/j.ejmech.2016.04.027},
year = {2016},
date = {2016-01-01},
journal = {European Journal of Medicinal Chemistry},
volume = {120},
pages = {1--12},
abstract = {Copper (II) complexes synthesized from the products of condensation of S-methyl- and S-benzyldithiocarbazate with 2,5-hexanedione (SMHDH2 and SBHDH2 respectively) have been characterized using various physicochemical (elemental analysis, molar conductivity, magnetic susceptibility) and spectroscopic (infrared, electronic) methods. The structures of SMHDH2, its copper (II) complex, CuSMHD, and the related CuSBHD complex as well as a pyrrole byproduct, SBPY, have been determined by single crystal X-ray diffraction. In order to provide more insight into the behaviour of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. Antibacterial activity and cytotoxicity were evaluated. The compounds, dissolved in 0.5% and 5% DMSO, showed a wide range of antibacterial activity against 10 strains of Gram-positive and Gram-negative bacteria. Investigations of the effects of efflux pumps and membrane penetration on antibacterial activity are reported herein. Antiproliferation activity was observed to be enhanced by complexation with copper. Preliminary screening showed Cu complexes are strongly active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. © 2016 Published by Elsevier Masson SAS.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Copper (II) complexes synthesized from the products of condensation of S-methyl- and S-benzyldithiocarbazate with 2,5-hexanedione (SMHDH2 and SBHDH2 respectively) have been characterized using various physicochemical (elemental analysis, molar conductivity, magnetic susceptibility) and spectroscopic (infrared, electronic) methods. The structures of SMHDH2, its copper (II) complex, CuSMHD, and the related CuSBHD complex as well as a pyrrole byproduct, SBPY, have been determined by single crystal X-ray diffraction. In order to provide more insight into the behaviour of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. Antibacterial activity and cytotoxicity were evaluated. The compounds, dissolved in 0.5% and 5% DMSO, showed a wide range of antibacterial activity against 10 strains of Gram-positive and Gram-negative bacteria. Investigations of the effects of efflux pumps and membrane penetration on antibacterial activity are reported herein. Antiproliferation activity was observed to be enhanced by complexation with copper. Preliminary screening showed Cu complexes are strongly active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. © 2016 Published by Elsevier Masson SAS. |
Human TTR conformation altered by rhenium tris-carbonyl derivatives Article de journal L Ciccone; C Policar; E A Stura; W Shepard Journal of Structural Biology, 195 (3), p. 353–364, 2016. @article{Ciccone:2016,
title = {Human TTR conformation altered by rhenium tris-carbonyl derivatives},
author = {L Ciccone and C Policar and E A Stura and W Shepard},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991363542&doi=10.1016%2fj.jsb.2016.07.002&partnerID=40&md5=86e7e8d956bfdb39ae832e52b01a9dea},
doi = {10.1016/j.jsb.2016.07.002},
year = {2016},
date = {2016-01-01},
journal = {Journal of Structural Biology},
volume = {195},
number = {3},
pages = {353--364},
abstract = {Transthyretin (TTR) is a 54 kDa homotetrameric serum protein that transports thyroxine (T4) and retinol. TTR is potentially amyloidogenic due to homotetramer dissociation into monomeric intermediates that self-assemble as amyloid deposits and insoluble fibrils. Most crystallographic structures, including those of amyloidogenic variants show the same tetramer without major variations in the monomer-monomer interface nor in the volume of the interdimeric cavity. Soaking TTR crystals in a solution containing rhenium tris-carbonyl derivatives yields a TTR conformer never observed before. Only one of the two monomers of the crystallographic dimer is significantly altered, and the inner part of the T4 binding cavity is expanded at one end and shrunk at the other. The result redefines the mechanism of allosteric communication between the two sites, suggesting that negative cooperativity is a function of dimer asymmetry, which can be induced through internal or external binding. An aspect that remains unexplained is why the conformational changes are ubiquitous throughout the crystal although the heavy metal content of the derivatized crystals is relatively low. The conformational changes observed, which include Leu82, may represent a form of TTR better at scavenging β-Amyloid. At a resolution of 1.69 r{A}, with excellent refinement statistics and well defined electron density for all parts of the structure, it is possible to envisage answering important questions that range from protein cooperative behavior to heavy atom induced protein conformational modifications that can result in crystallographic non-isomorphism. © 2016 Elsevier Inc.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Transthyretin (TTR) is a 54 kDa homotetrameric serum protein that transports thyroxine (T4) and retinol. TTR is potentially amyloidogenic due to homotetramer dissociation into monomeric intermediates that self-assemble as amyloid deposits and insoluble fibrils. Most crystallographic structures, including those of amyloidogenic variants show the same tetramer without major variations in the monomer-monomer interface nor in the volume of the interdimeric cavity. Soaking TTR crystals in a solution containing rhenium tris-carbonyl derivatives yields a TTR conformer never observed before. Only one of the two monomers of the crystallographic dimer is significantly altered, and the inner part of the T4 binding cavity is expanded at one end and shrunk at the other. The result redefines the mechanism of allosteric communication between the two sites, suggesting that negative cooperativity is a function of dimer asymmetry, which can be induced through internal or external binding. An aspect that remains unexplained is why the conformational changes are ubiquitous throughout the crystal although the heavy metal content of the derivatized crystals is relatively low. The conformational changes observed, which include Leu82, may represent a form of TTR better at scavenging β-Amyloid. At a resolution of 1.69 Å, with excellent refinement statistics and well defined electron density for all parts of the structure, it is possible to envisage answering important questions that range from protein cooperative behavior to heavy atom induced protein conformational modifications that can result in crystallographic non-isomorphism. © 2016 Elsevier Inc. |
Monitoring bicosomes containing antioxidants in normal and irradiated skin Article de journal E Fernández; S Hostachy; C Sandt; G Rodríguez; H C Bertrand; S Clède; M Cócera; A D L Maza; F Lambert; C Policar; O López RSC Advances, 6 (76), p. 72559–72567, 2016. @article{Fernandez:2016,
title = {Monitoring bicosomes containing antioxidants in normal and irradiated skin},
author = {E Fern\'{a}ndez and S Hostachy and C Sandt and G Rodr\'{i}guez and H C Bertrand and S Cl\`{e}de and M C\'{o}cera and A D L Maza and F Lambert and C Policar and O L\'{o}pez},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84982684419&doi=10.1039%2fc6ra11170j&partnerID=40&md5=126bef944046a09450ae86ce5985c07f},
doi = {10.1039/c6ra11170j},
year = {2016},
date = {2016-01-01},
journal = {RSC Advances},
volume = {6},
number = {76},
pages = {72559--72567},
abstract = {This study evaluates the penetration of bicosome systems incorporating two different antioxidants into normal skin and skin exposed to ultraviolet-visible radiation (UV-VIS) by Fourier-transform infrared microspectroscopy (FT-IR) using synchrotron radiation. Bicosomes are phospholipid assemblies based on mixtures of discoidal lipid structures protected by spherical lipid vesicles able to incorporate different molecules. In the current work, the antioxidants incorporated in these systems were β-carotene and a Mn complex as a superoxide dismutase (SOD) mimic. Additionally, a rhenium tri-carbonyl derivative was incorporated in the bicosome systems in order to map their penetration following the tag specific carbonyl signal by FT-IR microspectroscopy. The characterization of bicosome systems using the dynamic light scattering technique (DLS) showed a modification in the size of the systems containing β-carotene (Bcβ) or MnII complex (BcMn). After skin permeation, FT-IR results indicated a higher and deeper penetration of the BcMn system than the Bcβ system into the skin. Likely, the different physicochemical properties of both antioxidants could be responsible for this effect. Moreover, the penetration of both bicosome systems in irradiated skin was lower in comparison with the normal skin. This fact could be a consequence of the alteration of water transport in the skin during the irradiation process. In conclusion, these results indicated the effectiveness of bicosome systems as skin carriers, and provide information to protect skin under radiation using antioxidants. © The Royal Society of Chemistry 2016.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This study evaluates the penetration of bicosome systems incorporating two different antioxidants into normal skin and skin exposed to ultraviolet-visible radiation (UV-VIS) by Fourier-transform infrared microspectroscopy (FT-IR) using synchrotron radiation. Bicosomes are phospholipid assemblies based on mixtures of discoidal lipid structures protected by spherical lipid vesicles able to incorporate different molecules. In the current work, the antioxidants incorporated in these systems were β-carotene and a Mn complex as a superoxide dismutase (SOD) mimic. Additionally, a rhenium tri-carbonyl derivative was incorporated in the bicosome systems in order to map their penetration following the tag specific carbonyl signal by FT-IR microspectroscopy. The characterization of bicosome systems using the dynamic light scattering technique (DLS) showed a modification in the size of the systems containing β-carotene (Bcβ) or MnII complex (BcMn). After skin permeation, FT-IR results indicated a higher and deeper penetration of the BcMn system than the Bcβ system into the skin. Likely, the different physicochemical properties of both antioxidants could be responsible for this effect. Moreover, the penetration of both bicosome systems in irradiated skin was lower in comparison with the normal skin. This fact could be a consequence of the alteration of water transport in the skin during the irradiation process. In conclusion, these results indicated the effectiveness of bicosome systems as skin carriers, and provide information to protect skin under radiation using antioxidants. © The Royal Society of Chemistry 2016. |
2015
|
Fast magnetically driven electrodeposition of amorphous metal oxide water oxidation catalysts from carbon-coated metallic nanoparticles Article de journal J Zhu; F Lambert; C Policar; F Mavré; B Limoges Journal of Materials Chemistry A, 3 (31), p. 16190–16197, 2015. @article{Zhu:2015,
title = {Fast magnetically driven electrodeposition of amorphous metal oxide water oxidation catalysts from carbon-coated metallic nanoparticles},
author = {J Zhu and F Lambert and C Policar and F Mavr\'{e} and B Limoges},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938100019&doi=10.1039%2fc5ta03430b&partnerID=40&md5=ac4e0e0dc5c94a4c574b14d5b17ac552},
doi = {10.1039/c5ta03430b},
year = {2015},
date = {2015-01-01},
journal = {Journal of Materials Chemistry A},
volume = {3},
number = {31},
pages = {16190--16197},
abstract = {We report a new approach for efficient electrodeposition of amorphous metal oxide water oxidation catalysts on an electrode surface. A catalytic metal-based film was obtained by means of anodic oxidation of metallic nanoparticles, namely carbon-coated cobalt nanoparticles or carbon-coated nickel nanoparticles. Interestingly, these particles are intrinsically conductive and possess magnetic properties which make it easy to collect them on an electrode surface using a simple magnet to form a porous conductive particulate film. Upon anodic polarization in an appropriate electrolyte, the particulate film is rapidly converted into an amorphous metal-based catalytic film that efficiently catalyzes the oxidation of water at neutral pH. Compared to Nocera's method based on anodic electrodeposition of a metal salt in solution, this new electrodeposition strategy offers the key advantage of supplying metal ions in a solid and metallic form, leading to a fast release of high local concentrations of metal ions right at the spot of the film formation (i.e., in the vicinity of the electrode surface). This plays a decisive role in the formation rate of the catalytic film, allowing the deposition of the oxygen-evolving catalyst in a remarkably short-time. Moreover, the methodology can be easily extended to a wide range of metal particles of different nature and sizes, and also to their mixtures, finally offering a new degree of flexibility and opportunities not only in the preparation of metal-based water oxidation catalysts, but also in the preparation of inorganic metal-based catalysts for hydrogen or oxygen evolution. © 2015 The Royal Society of Chemistry.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report a new approach for efficient electrodeposition of amorphous metal oxide water oxidation catalysts on an electrode surface. A catalytic metal-based film was obtained by means of anodic oxidation of metallic nanoparticles, namely carbon-coated cobalt nanoparticles or carbon-coated nickel nanoparticles. Interestingly, these particles are intrinsically conductive and possess magnetic properties which make it easy to collect them on an electrode surface using a simple magnet to form a porous conductive particulate film. Upon anodic polarization in an appropriate electrolyte, the particulate film is rapidly converted into an amorphous metal-based catalytic film that efficiently catalyzes the oxidation of water at neutral pH. Compared to Nocera's method based on anodic electrodeposition of a metal salt in solution, this new electrodeposition strategy offers the key advantage of supplying metal ions in a solid and metallic form, leading to a fast release of high local concentrations of metal ions right at the spot of the film formation (i.e., in the vicinity of the electrode surface). This plays a decisive role in the formation rate of the catalytic film, allowing the deposition of the oxygen-evolving catalyst in a remarkably short-time. Moreover, the methodology can be easily extended to a wide range of metal particles of different nature and sizes, and also to their mixtures, finally offering a new degree of flexibility and opportunities not only in the preparation of metal-based water oxidation catalysts, but also in the preparation of inorganic metal-based catalysts for hydrogen or oxygen evolution. © 2015 The Royal Society of Chemistry. |
Metal-carbonyl units for vibrational and luminescence imaging: Towards multimodality Article de journal S Clède; C Policar Chemistry - A European Journal, 21 (3), p. 942–958, 2015. @article{Clede:2015,
title = {Metal-carbonyl units for vibrational and luminescence imaging: Towards multimodality},
author = {S Cl\`{e}de and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920784874&doi=10.1002%2fchem.201404600&partnerID=40&md5=eaf7654638733b121ed1fe744e71b7b5},
doi = {10.1002/chem.201404600},
year = {2015},
date = {2015-01-01},
journal = {Chemistry - A European Journal},
volume = {21},
number = {3},
pages = {942--958},
abstract = {Metal-carbonyl complexes are attractive structures for bio-imaging. In addition to unique vibrational properties due to the CO moieties enabling IR and Raman cell imaging, the appropriate choice of ancillary ligands opens up the opportunity for luminescence detection. Through a classification by techniques, past and recent developments in the application of metal-carbonyl complexes for vibrational and luminescence bio-imaging are reviewed. Finally, their potential as bimodal IR and luminescent probes is addressed. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Metal-carbonyl complexes are attractive structures for bio-imaging. In addition to unique vibrational properties due to the CO moieties enabling IR and Raman cell imaging, the appropriate choice of ancillary ligands opens up the opportunity for luminescence detection. Through a classification by techniques, past and recent developments in the application of metal-carbonyl complexes for vibrational and luminescence bio-imaging are reviewed. Finally, their potential as bimodal IR and luminescent probes is addressed. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA. |
Synthesis, characterization and biological activity of Cu(II), Zn(II) and Re(I) complexes derived from S-benzyldithiocarbazate and 3-acetylcoumarin Article de journal M L Low; G Paulus; P Dorlet; R Guillot; R Rosli; N Delsuc; K A Crouse; C Policar BioMetals, 28 (3), p. 553–566, 2015. @article{Low:2015,
title = {Synthesis, characterization and biological activity of Cu(II), Zn(II) and Re(I) complexes derived from S-benzyldithiocarbazate and 3-acetylcoumarin},
author = {M L Low and G Paulus and P Dorlet and R Guillot and R Rosli and N Delsuc and K A Crouse and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939939059&doi=10.1007%2fs10534-015-9831-2&partnerID=40&md5=8d0220a2a88cc9eb122f191d65c87199},
doi = {10.1007/s10534-015-9831-2},
year = {2015},
date = {2015-01-01},
journal = {BioMetals},
volume = {28},
number = {3},
pages = {553--566},
abstract = {Cu(II), Zn(II) and Re(I) complexes have been synthesized with the Schiff base, N′-[1-(2-oxo-2H-chromen-3-yl)-ethylidene]-hydrazinecarbodithioic acid benzyl ester (SBCM-H) which was prepared by condensation of S-benzyldithiocarbazate and 3-acetylcoumarin. The metal complexes were characterized on the basis of various physico-chemical and spectroscopic techniques including elemental analysis and electrochemical studies, and FT-IR, UV-Vis, NMR, EPR and mass spectroscopy. The Schiff base was found to behave as a bidentate ligand coordinating with Cu(II) and Zn(II) in the thiolate form with 1:2 metal to ligand stoichiometry. Crystals suitable for X-ray diffractometry (XRD) were obtained from the reaction of ReCl(CO)5 with SBCM-H forming a centrosymmetric dimeric complex Re2L2(CO)6 linked by Re-S-Re bridges, where S is the thiolate sulfur of the N,S-bidentate ligand. This Re(I) complex is the first metal carbonyl complex with a bidentate dithiocarbazate ligand to have been characterized by XRD. Cytotoxicity assays revealed enhancement of the bioactivity of SBCM-H upon complexation. Both Cu(II) and Re(I) complexes are found to be active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. Graphical Abstract: TOC diagram [Figure not available: see fulltext.] © 2015 Springer Science+Business Media New York.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Cu(II), Zn(II) and Re(I) complexes have been synthesized with the Schiff base, N′-[1-(2-oxo-2H-chromen-3-yl)-ethylidene]-hydrazinecarbodithioic acid benzyl ester (SBCM-H) which was prepared by condensation of S-benzyldithiocarbazate and 3-acetylcoumarin. The metal complexes were characterized on the basis of various physico-chemical and spectroscopic techniques including elemental analysis and electrochemical studies, and FT-IR, UV-Vis, NMR, EPR and mass spectroscopy. The Schiff base was found to behave as a bidentate ligand coordinating with Cu(II) and Zn(II) in the thiolate form with 1:2 metal to ligand stoichiometry. Crystals suitable for X-ray diffractometry (XRD) were obtained from the reaction of ReCl(CO)5 with SBCM-H forming a centrosymmetric dimeric complex Re2L2(CO)6 linked by Re-S-Re bridges, where S is the thiolate sulfur of the N,S-bidentate ligand. This Re(I) complex is the first metal carbonyl complex with a bidentate dithiocarbazate ligand to have been characterized by XRD. Cytotoxicity assays revealed enhancement of the bioactivity of SBCM-H upon complexation. Both Cu(II) and Re(I) complexes are found to be active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. Graphical Abstract: TOC diagram [Figure not available: see fulltext.] © 2015 Springer Science+Business Media New York. |
Nanometric distance measurements between Mn(II)DOTA centers Article de journal H Y Vincent Ching; P Demay-Drouhard; H C Bertrand; C Policar; L C Tabares; S Un Physical Chemistry Chemical Physics, 17 (36), p. 23368–23377, 2015. @article{VincentChing:2015,
title = {Nanometric distance measurements between Mn(II)DOTA centers},
author = {H Y Vincent Ching and P Demay-Drouhard and H C Bertrand and C Policar and L C Tabares and S Un},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941299721&doi=10.1039%2fc5cp03487f&partnerID=40&md5=bfd7a9aac0fc115147eb207f0fbeb05b},
doi = {10.1039/c5cp03487f},
year = {2015},
date = {2015-01-01},
journal = {Physical Chemistry Chemical Physics},
volume = {17},
number = {36},
pages = {23368--23377},
abstract = {Pulse electron-electron double resonance (PELDOR) is a versatile technique for probing the structures and functions of complex biological systems. Despite the recent interest in high-spin metal-ions for high field/frequency applications, PELDOR measurements of Mn(II) remain relatively underexplored. Here we present Mn(II)-Mn(II) PELDOR distance measurements at 94 GHz on polyproline II (PPII) helices doubly spin-labeled with Mn(II)DOTA, which are distinguished by their small zero-field interaction. The measured Mn-Mn distances and distribution profiles were in good agreement with the expected values from molecular models. Additional features in the frequency-domain spectra became apparent at certain combinations of detect and pump frequencies. Spin-Hamiltonian calculations showed that they likely arose from contributions from the pseudo-secular component of the dipolar interaction that were found to be non-negligible for Mn(II)DOTA. However, the influence of the pseudo-secular component on the distance distribution profiles apparently was limited. The results show the potential of Mn(II)DOTA spin labels for high-field PELDOR distance measurements in proteins and other biological systems. © the Owner Societies 2015.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Pulse electron-electron double resonance (PELDOR) is a versatile technique for probing the structures and functions of complex biological systems. Despite the recent interest in high-spin metal-ions for high field/frequency applications, PELDOR measurements of Mn(II) remain relatively underexplored. Here we present Mn(II)-Mn(II) PELDOR distance measurements at 94 GHz on polyproline II (PPII) helices doubly spin-labeled with Mn(II)DOTA, which are distinguished by their small zero-field interaction. The measured Mn-Mn distances and distribution profiles were in good agreement with the expected values from molecular models. Additional features in the frequency-domain spectra became apparent at certain combinations of detect and pump frequencies. Spin-Hamiltonian calculations showed that they likely arose from contributions from the pseudo-secular component of the dipolar interaction that were found to be non-negligible for Mn(II)DOTA. However, the influence of the pseudo-secular component on the distance distribution profiles apparently was limited. The results show the potential of Mn(II)DOTA spin labels for high-field PELDOR distance measurements in proteins and other biological systems. © the Owner Societies 2015. |
Entasis through Hook-and-Loop fastening in a glycoligand with cumulative weak forces stabilizing CuI Article de journal L Garcia; F Cisnetti; N Gillet; R Guillot; M Aumont-Nicaise; J -P Piquemal; M Desmadril; F Lambert; C Policar Journal of the American Chemical Society, 137 (3), p. 1141–1146, 2015. @article{Garcia:2015,
title = {Entasis through Hook-and-Loop fastening in a glycoligand with cumulative weak forces stabilizing CuI},
author = {L Garcia and F Cisnetti and N Gillet and R Guillot and M Aumont-Nicaise and J -P Piquemal and M Desmadril and F Lambert and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921832039&doi=10.1021%2fja510259p&partnerID=40&md5=eb31b469985f0f4759bf0f0869f067c9},
doi = {10.1021/ja510259p},
year = {2015},
date = {2015-01-01},
journal = {Journal of the American Chemical Society},
volume = {137},
number = {3},
pages = {1141--1146},
abstract = {The idea of a possible control of metal ion properties by constraining the coordination sphere geometry was introduced by Vallee and Williams with the concept of entasis, which is frequently postulated to be at stake in metallobiomolecules. However, the interactions controlling the geometry at metal centers remain often elusive. In this study, the coordination properties toward copper ions - CuII or CuI - of a geometrically constrained glycoligand centered on a sugar scaffold were compared with those of an analogous ligand built on an unconstrained alkyl chain. The sugar-centered ligand was shown to be more preorganized for CuII coordination than its open-chain analogue, with an unusual additional stabilization of the CuI redox state. This preference for CuI was suggested to arise from geometric constraints favoring an optimized folding of the glycoligand minimizing steric repulsions. In other words, the CuI d10 species is stabilized by valence shell electron pair repulsion (VSEPR). This idea was rationalized by a theoretical noncovalent interactions (NCI) analysis. The cumulative effects of weak forces were shown to create an efficient buckle as in a hook-and-loop fastener, and fine structural features within the glycoligand reduce repulsive interactions for the CuI state. This study emphasizes that monosaccharide platforms are appropriate ligand backbones for a delicate geometric control at the metal center, with a network of weak interactions within the ligand. This structuration availing in glycoligands makes them attractive for metallic entasis. © 2015 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The idea of a possible control of metal ion properties by constraining the coordination sphere geometry was introduced by Vallee and Williams with the concept of entasis, which is frequently postulated to be at stake in metallobiomolecules. However, the interactions controlling the geometry at metal centers remain often elusive. In this study, the coordination properties toward copper ions - CuII or CuI - of a geometrically constrained glycoligand centered on a sugar scaffold were compared with those of an analogous ligand built on an unconstrained alkyl chain. The sugar-centered ligand was shown to be more preorganized for CuII coordination than its open-chain analogue, with an unusual additional stabilization of the CuI redox state. This preference for CuI was suggested to arise from geometric constraints favoring an optimized folding of the glycoligand minimizing steric repulsions. In other words, the CuI d10 species is stabilized by valence shell electron pair repulsion (VSEPR). This idea was rationalized by a theoretical noncovalent interactions (NCI) analysis. The cumulative effects of weak forces were shown to create an efficient buckle as in a hook-and-loop fastener, and fine structural features within the glycoligand reduce repulsive interactions for the CuI state. This study emphasizes that monosaccharide platforms are appropriate ligand backbones for a delicate geometric control at the metal center, with a network of weak interactions within the ligand. This structuration availing in glycoligands makes them attractive for metallic entasis. © 2015 American Chemical Society. |
An easy-to-detect nona-arginine peptide for epidermal targeting Article de journal S Clède; N Delsuc; C Laugel; F Lambert; C Sandt; A Baillet-Guffroy; C Policar Chemical Communications, 51 (13), p. 2687–2689, 2015. @article{Clede:2015a,
title = {An easy-to-detect nona-arginine peptide for epidermal targeting},
author = {S Cl\`{e}de and N Delsuc and C Laugel and F Lambert and C Sandt and A Baillet-Guffroy and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922637409&doi=10.1039%2fc4cc08737b&partnerID=40&md5=a0e333e8498570e4d4ceb500066d9c1e},
doi = {10.1039/c4cc08737b},
year = {2015},
date = {2015-01-01},
journal = {Chemical Communications},
volume = {51},
number = {13},
pages = {2687--2689},
abstract = {A correlative approach combining synchrotron radiation based IR microscopy and fluorescence microscopy enabled the successful detection and quantification of a nona-arginine peptide labelled with a Single Core Multimodal Probe for Imaging (SCoMPI) in skin biopsies. The topical penetration of the conjugate appeared to be time dependent and occurred most probably via the extracellular matrix. This journal is © The Royal Society of Chemistry 2015.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A correlative approach combining synchrotron radiation based IR microscopy and fluorescence microscopy enabled the successful detection and quantification of a nona-arginine peptide labelled with a Single Core Multimodal Probe for Imaging (SCoMPI) in skin biopsies. The topical penetration of the conjugate appeared to be time dependent and occurred most probably via the extracellular matrix. This journal is © The Royal Society of Chemistry 2015. |
2014
|
Influence of the side-chain length on the cellular uptake and the cytotoxicity of rhenium triscarbonyl derivatives: A bimodal infrared and luminescence quantitative study Article de journal S Clède; F Lambert; R Saint-Fort; M -A Plamont; H Bertrand; A Vessières; C Policar Chemistry - A European Journal, 20 (28), p. 8714–8722, 2014. @article{Clede:2014,
title = {Influence of the side-chain length on the cellular uptake and the cytotoxicity of rhenium triscarbonyl derivatives: A bimodal infrared and luminescence quantitative study},
author = {S Cl\`{e}de and F Lambert and R Saint-Fort and M -A Plamont and H Bertrand and A Vessi\`{e}res and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903724808&doi=10.1002%2fchem.201402471&partnerID=40&md5=7334edd420d748a4418df936173a79b9},
doi = {10.1002/chem.201402471},
year = {2014},
date = {2014-01-01},
journal = {Chemistry - A European Journal},
volume = {20},
number = {28},
pages = {8714--8722},
abstract = {Rhenium triscarbonyl complexes fac-[Re(CO)3(NtextasciicircumN)] with appropriate ancillary NtextasciicircumN ligands are relevant for fluorescent bio-imaging. Recently, we have shown that [Re(CO)3] cores can also be efficiently mapped inside cells using their IR signature and that they can thus be used in a bimodal approach. To describe them we have coined the term SCoMPIs for single-core multimodal probes for imaging. In the context of the use of these SCoMPIs in bio-imaging, the questions of their cellular uptake and cytotoxicity are critical. We report here a series of compounds derived from the [Re(CO) 3Cl(pyta)] core (pyta=4-(2-pyridyl)-1,2,3-triazole). The pyta ligand is of interest because it can be easily functionalized. Aliphatic side chains (C4, C8, and C12) were appended to this core. A correlative study involving IR and luminescence was performed to monitor and quantify their cellular internalization. We studied the relationship between lipophilicity (log P(o/w)), cytotoxicity (IC50), and cellular uptake, and we showed that both uptake and cytotoxicity increase with the length of the side chain, with a higher uptake for the C12 derivative. This study stresses the distinction that has to be made between apparent toxicity, determined as an incubation concentration IC50, and intrinsic toxicity. Indeed, the intrinsic toxicity of a compound can remain hidden if it is not cell permeable. Therefore it must be kept in mind that IC50 values are composite values, reflecting both cellular uptake and intrinsic toxicity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Rhenium triscarbonyl complexes fac-[Re(CO)3(NtextasciicircumN)] with appropriate ancillary NtextasciicircumN ligands are relevant for fluorescent bio-imaging. Recently, we have shown that [Re(CO)3] cores can also be efficiently mapped inside cells using their IR signature and that they can thus be used in a bimodal approach. To describe them we have coined the term SCoMPIs for single-core multimodal probes for imaging. In the context of the use of these SCoMPIs in bio-imaging, the questions of their cellular uptake and cytotoxicity are critical. We report here a series of compounds derived from the [Re(CO) 3Cl(pyta)] core (pyta=4-(2-pyridyl)-1,2,3-triazole). The pyta ligand is of interest because it can be easily functionalized. Aliphatic side chains (C4, C8, and C12) were appended to this core. A correlative study involving IR and luminescence was performed to monitor and quantify their cellular internalization. We studied the relationship between lipophilicity (log P(o/w)), cytotoxicity (IC50), and cellular uptake, and we showed that both uptake and cytotoxicity increase with the length of the side chain, with a higher uptake for the C12 derivative. This study stresses the distinction that has to be made between apparent toxicity, determined as an incubation concentration IC50, and intrinsic toxicity. Indeed, the intrinsic toxicity of a compound can remain hidden if it is not cell permeable. Therefore it must be kept in mind that IC50 values are composite values, reflecting both cellular uptake and intrinsic toxicity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Apo-neocarzinostatin: A protein carrier for Cu(II) glycocomplexes and Cu(II) into U937 and HT29 cell lines Article de journal L Garcia; S Franzoni; F Mussi; M Aumont-Niçaise; H Bertrand; M Desmadril; G Pelosi; A Buschini; C Policar Journal of Inorganic Biochemistry, 135 , p. 40–44, 2014. @article{Garcia:2014,
title = {Apo-neocarzinostatin: A protein carrier for Cu(II) glycocomplexes and Cu(II) into U937 and HT29 cell lines},
author = {L Garcia and S Franzoni and F Mussi and M Aumont-Ni\c{c}aise and H Bertrand and M Desmadril and G Pelosi and A Buschini and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896943429&doi=10.1016%2fj.jinorgbio.2014.02.006&partnerID=40&md5=81ab9f0bb44feb00966cfb5735d8901a},
doi = {10.1016/j.jinorgbio.2014.02.006},
year = {2014},
date = {2014-01-01},
journal = {Journal of Inorganic Biochemistry},
volume = {135},
pages = {40--44},
abstract = {In the field of pharmaceuticals there is an increasing need for new delivery systems to overcome the issues of solubility, penetration, toxicity and drug resistance. One of the possible strategies is to use biocarriers such as proteins to encourage the cell-penetration of drugs. In this paper, the use of the apo-protein neocarzinostatin (apo-NCS) as a carrier-protein for two Cu(II) glycocomplexes, previously characterized, and Cu(II) ions was investigated. Its interaction with the metallic compounds was analyzed using microcalorimetry. The dissociation constants were shown to be in the micromolar range. The Cu(II) glycocomplexes, in absence of apo-NCS, were found to be cytotoxic in the U937 and HT29 cell lines whereas the corresponding glycoligands showed no toxicity. The leukemic cell line (U937) seems to be more sensitive to glycocomplexes than the colon cancer cell line (HT29). Interestingly, apo-NCS was shown to increase systematically the antiproliferative activity by a factor of 2 and 3 for Cu(II) glycocomplexes and Cu(II) respectively. The antiproliferative activity detected was not related to proteasome inhibition. This result stresses the importance of new molecular tools for the delivery of Cu(II) to tumor cells using non-covalent association with carriers proteins. © 2014 Elsevier Inc. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In the field of pharmaceuticals there is an increasing need for new delivery systems to overcome the issues of solubility, penetration, toxicity and drug resistance. One of the possible strategies is to use biocarriers such as proteins to encourage the cell-penetration of drugs. In this paper, the use of the apo-protein neocarzinostatin (apo-NCS) as a carrier-protein for two Cu(II) glycocomplexes, previously characterized, and Cu(II) ions was investigated. Its interaction with the metallic compounds was analyzed using microcalorimetry. The dissociation constants were shown to be in the micromolar range. The Cu(II) glycocomplexes, in absence of apo-NCS, were found to be cytotoxic in the U937 and HT29 cell lines whereas the corresponding glycoligands showed no toxicity. The leukemic cell line (U937) seems to be more sensitive to glycocomplexes than the colon cancer cell line (HT29). Interestingly, apo-NCS was shown to increase systematically the antiproliferative activity by a factor of 2 and 3 for Cu(II) glycocomplexes and Cu(II) respectively. The antiproliferative activity detected was not related to proteasome inhibition. This result stresses the importance of new molecular tools for the delivery of Cu(II) to tumor cells using non-covalent association with carriers proteins. © 2014 Elsevier Inc. All rights reserved. |
Electrochemical formation and reactivity of a manganese peroxo complex: Acid driven Ħ2O2 generation vs. O-O bond cleavage Article de journal H Y V Ching; E Anxolabéhère-Mallart; H E Colmer; C Costentin; P Dorlet; T A Jackson; C Policar; M Robert Chemical Science, 5 (6), p. 2304–2310, 2014. @article{Ching:2014,
title = {Electrochemical formation and reactivity of a manganese peroxo complex: Acid driven {H}2O2 generation vs. O-O bond cleavage},
author = {H Y V Ching and E Anxolab\'{e}h\`{e}re-Mallart and H E Colmer and C Costentin and P Dorlet and T A Jackson and C Policar and M Robert},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900329910&doi=10.1039%2fc3sc53469c&partnerID=40&md5=8b4ecc598d6455d82b1681e608484bc1},
doi = {10.1039/c3sc53469c},
year = {2014},
date = {2014-01-01},
journal = {Chemical Science},
volume = {5},
number = {6},
pages = {2304--2310},
abstract = {The formation of a side-on peroxo [MnIIIL(O2)] complex (L = phenolato-containing pentadentate ligand), resulting from the reaction of electrochemically reduced O2 and [MnIIL] +, is monitored in DMF using cyclic voltammetry, low temperature electronic absorption spectroscopy and electron paramagnetic resonance spectroscopy. Mechanistic studies based on cyclic voltammetry reveal that upon addition of a strong acid the Mn-O bond is broken, resulting in the release of H2O2, whereas in the presence of a weak acid the O-O bond is cleaved via a concerted dissociative electron transfer. This dichotomy of M-O versus O-O bond cleavage is unprecedented for peroxomanganese(iii) complexes and the latter offers a route for electrochemical O2 activation by a manganese(ii) complex. This journal is © the Partner Organisations 2014.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The formation of a side-on peroxo [MnIIIL(O2)] complex (L = phenolato-containing pentadentate ligand), resulting from the reaction of electrochemically reduced O2 and [MnIIL] +, is monitored in DMF using cyclic voltammetry, low temperature electronic absorption spectroscopy and electron paramagnetic resonance spectroscopy. Mechanistic studies based on cyclic voltammetry reveal that upon addition of a strong acid the Mn-O bond is broken, resulting in the release of H2O2, whereas in the presence of a weak acid the O-O bond is cleaved via a concerted dissociative electron transfer. This dichotomy of M-O versus O-O bond cleavage is unprecedented for peroxomanganese(iii) complexes and the latter offers a route for electrochemical O2 activation by a manganese(ii) complex. This journal is © the Partner Organisations 2014. |
Anti-oxidant Mn-complexes: evaluation in cellular models of oxidative stress Article de journal Clotilde Policar; Anne-Sophie Bernard; Nicolas Delsuc; Geraldine Gazzah; Manon Guille; Frederic Lemaitre; Christian Amatore; Maria Bachelet; Joelle Masliah Journal of Biological Inorganic Chemistry, 19 , p. S739-S740, 2014, (Times Cited: 0
2
12th European Biological Inorganic Chemistry Conference (EuroBIC)
Aug 24-28, 2014
Zurich, SWITZERLAND
Univ Zurich). @article{,
title = {Anti-oxidant Mn-complexes: evaluation in cellular models of oxidative stress},
author = {Clotilde Policar and Anne-Sophie Bernard and Nicolas Delsuc and Geraldine Gazzah and Manon Guille and Frederic Lemaitre and Christian Amatore and Maria Bachelet and Joelle Masliah},
year = {2014},
date = {2014-01-01},
journal = {Journal of Biological Inorganic Chemistry},
volume = {19},
pages = {S739-S740},
note = {Times Cited: 0
2
12th European Biological Inorganic Chemistry Conference (EuroBIC)
Aug 24-28, 2014
Zurich, SWITZERLAND
Univ Zurich},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
Conjugation of a new series of dithiocarbazate schiff base copper(II) complexes with vectors selected to enhance antibacterial activity Article de journal M L Low; L Maigre; P Dorlet; R Guillot; J -M Pagès; K A Crouse; C Policar; N Delsuc Bioconjugate Chemistry, 25 (12), p. 2269–2284, 2014. @article{Low:2014,
title = {Conjugation of a new series of dithiocarbazate schiff base copper(II) complexes with vectors selected to enhance antibacterial activity},
author = {M L Low and L Maigre and P Dorlet and R Guillot and J -M Pag\`{e}s and K A Crouse and C Policar and N Delsuc},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84918505283&doi=10.1021%2fbc5004907&partnerID=40&md5=d51ad81235fa7fd9aec14b7acd2c908a},
doi = {10.1021/bc5004907},
year = {2014},
date = {2014-01-01},
journal = {Bioconjugate Chemistry},
volume = {25},
number = {12},
pages = {2269--2284},
abstract = {A new series of six Schiff bases derived from S-methyldithiocarbazate (SMDTC) and S-benzyldithiocarbazate (SBDTC) with methyl levulinate (SMML, SBML), levulinic acid (SMLA, SBLA), and 4-carboxybenzaldehyde (SM4CB, SB4CB) were reacted with copper(II), producing complexes of general formula MLtextlessinftextgreater2textless/inftextgreater (M = Cu(II)},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A new series of six Schiff bases derived from S-methyldithiocarbazate (SMDTC) and S-benzyldithiocarbazate (SBDTC) with methyl levulinate (SMML, SBML), levulinic acid (SMLA, SBLA), and 4-carboxybenzaldehyde (SM4CB, SB4CB) were reacted with copper(II), producing complexes of general formula MLtextlessinftextgreater2textless/inftextgreater (M = Cu(II) |
Luminescence modulations of rhenium tricarbonyl complexes induced by structural variations Article de journal H C Bertrand; S Clède; R Guillot; F Lambert; C Policar Inorganic Chemistry, 53 (12), p. 6204–6223, 2014. @article{Bertrand:2014,
title = {Luminescence modulations of rhenium tricarbonyl complexes induced by structural variations},
author = {H C Bertrand and S Cl\`{e}de and R Guillot and F Lambert and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902530649&doi=10.1021%2fic5007007&partnerID=40&md5=f3030a715ad7c095b013503a9d5b44a8},
doi = {10.1021/ic5007007},
year = {2014},
date = {2014-01-01},
journal = {Inorganic Chemistry},
volume = {53},
number = {12},
pages = {6204--6223},
abstract = {Octahedral d6 low-spin Re(I) tricarbonyl complexes are of considerable interest as noninvasive imaging probes and have been deeply studied owing to their biological stability, low toxicity, large Stokes shifts, and long luminescence lifetimes. We reported recently the bimodal IR and luminescence imaging of a Re(I) tricarbonyl complex with a Pyta ligand (4-(2-pyridyl)-1,2,3-triazole) in cells and labeled such metal-carbonyl complexes SCoMPIs for single-core multimodal probes for imaging. Re(I) tricarbonyl complexes have unique photophysical properties allowing for their unequivocal detection in cells but also present some weaknesses such as a very low luminescence quantum yield in aqueous medium. Further optimizations would thus be desirable. We therefore developed new Re(I) tricarbonyl complexes prepared from different ancillary ligands. Complexes with benzothiadiazole- triazole ligands show interesting luminescent quantum yields in acetonitrile and may constitute valuable luminescent metal complexes in organic media. A series of complexes with bidentate 1-(2-quinolinyl)-1,2,3-triazole (Taquin) and 1-(2-pyridyl)-1,2,3-triazole (Tapy) ligands bearing various 4-substituted alkyl side chains has been designed and synthesized with efficient procedures. Their photophysical properties have been characterized in acetonitrile and in a H 2O/DMSO (98/2) mixture and compared with those of the parent Quinta- and Pyta-based complexes. Tapy complexes bearing long alkyl chains show impressive enhancement of their luminescent properties relative to the parent Pyta complex. Theoretical calculations have been performed to further characterize this new class of rhenium tricarbonyl complexes. Preliminary cellular imaging studies in MDA-MB231 breast cancer cells reveal a strong increase in the luminescence signal in cells incubated with the Tapy complex substituted with a C12 alkyl chain. This study points out the interesting potential of the Tapy ligand in coordination chemistry, which has been so far underexploited. © 2014 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Octahedral d6 low-spin Re(I) tricarbonyl complexes are of considerable interest as noninvasive imaging probes and have been deeply studied owing to their biological stability, low toxicity, large Stokes shifts, and long luminescence lifetimes. We reported recently the bimodal IR and luminescence imaging of a Re(I) tricarbonyl complex with a Pyta ligand (4-(2-pyridyl)-1,2,3-triazole) in cells and labeled such metal-carbonyl complexes SCoMPIs for single-core multimodal probes for imaging. Re(I) tricarbonyl complexes have unique photophysical properties allowing for their unequivocal detection in cells but also present some weaknesses such as a very low luminescence quantum yield in aqueous medium. Further optimizations would thus be desirable. We therefore developed new Re(I) tricarbonyl complexes prepared from different ancillary ligands. Complexes with benzothiadiazole- triazole ligands show interesting luminescent quantum yields in acetonitrile and may constitute valuable luminescent metal complexes in organic media. A series of complexes with bidentate 1-(2-quinolinyl)-1,2,3-triazole (Taquin) and 1-(2-pyridyl)-1,2,3-triazole (Tapy) ligands bearing various 4-substituted alkyl side chains has been designed and synthesized with efficient procedures. Their photophysical properties have been characterized in acetonitrile and in a H 2O/DMSO (98/2) mixture and compared with those of the parent Quinta- and Pyta-based complexes. Tapy complexes bearing long alkyl chains show impressive enhancement of their luminescent properties relative to the parent Pyta complex. Theoretical calculations have been performed to further characterize this new class of rhenium tricarbonyl complexes. Preliminary cellular imaging studies in MDA-MB231 breast cancer cells reveal a strong increase in the luminescence signal in cells incubated with the Tapy complex substituted with a C12 alkyl chain. This study points out the interesting potential of the Tapy ligand in coordination chemistry, which has been so far underexploited. © 2014 American Chemical Society. |
Fourier transform infrared (FT-IR) spectromicroscopy to identify cell organelles: Correlation with fluorescence staining in MCF-7 breast cancer cells Article de journal S Clède; C Policar; C Sandt Applied Spectroscopy, 68 (1), p. 113–117, 2014. @article{Clede:2014a,
title = {Fourier transform infrared (FT-IR) spectromicroscopy to identify cell organelles: Correlation with fluorescence staining in MCF-7 breast cancer cells},
author = {S Cl\`{e}de and C Policar and C Sandt},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893060662&doi=10.1366%2f13-07139&partnerID=40&md5=f492b0918395dff47f71071460ac1f20},
doi = {10.1366/13-07139},
year = {2014},
date = {2014-01-01},
journal = {Applied Spectroscopy},
volume = {68},
number = {1},
pages = {113--117},
abstract = {Biomolecules display specific vibrational signatures in the infrared (IR) range, and organelles that concentrate these biomolecules can be identified by these IR signatures. Subcellular identification and location of cell organelles using IR signatures is attractive as it does not require the use of any specific trackers and is thus noninvasive and non-destructive. We show here that endogenous IR absorptions are relevant to detecting and imaging the nucleus, the cytoplasm, and the Golgi apparatus/endoplasmic reticulum in MCF- 7 breast cancer cells, and we compare these results with our previous work on the HeLa cell line. We correlate maps of fixed and dried cells obtained by synchrotron radiation Fourier transform infrared (SR FT-IR) spectromicroscopy with epifluorescence images using fluorescent trackers for Golgi apparatus and nucleus, namely BODIPY TR C5-ceramide complexed to BSA and DAPI, respectively. Interestingly, the ratios of the IR bands CH2:CH 3 (both asymmetric and symmetric) and CO(ester):amide I were shown to be reliable gauges of the lipidic character of a cellular compartment, the -CH2 and the CO(ester) absorptions increasing with the presence of inner membranes like in the Golgi apparatus. © 2014 Society for Applied Spectroscopy.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Biomolecules display specific vibrational signatures in the infrared (IR) range, and organelles that concentrate these biomolecules can be identified by these IR signatures. Subcellular identification and location of cell organelles using IR signatures is attractive as it does not require the use of any specific trackers and is thus noninvasive and non-destructive. We show here that endogenous IR absorptions are relevant to detecting and imaging the nucleus, the cytoplasm, and the Golgi apparatus/endoplasmic reticulum in MCF- 7 breast cancer cells, and we compare these results with our previous work on the HeLa cell line. We correlate maps of fixed and dried cells obtained by synchrotron radiation Fourier transform infrared (SR FT-IR) spectromicroscopy with epifluorescence images using fluorescent trackers for Golgi apparatus and nucleus, namely BODIPY TR C5-ceramide complexed to BSA and DAPI, respectively. Interestingly, the ratios of the IR bands CH2:CH 3 (both asymmetric and symmetric) and CO(ester):amide I were shown to be reliable gauges of the lipidic character of a cellular compartment, the -CH2 and the CO(ester) absorptions increasing with the presence of inner membranes like in the Golgi apparatus. © 2014 Society for Applied Spectroscopy. |
From IR-Spectromicroscopy using AFM-IR and SR-FTIR to Bimodal Spectromicroscopy using SCoMPIs - Single Core Multimodal Probe for Imaging Article de journal C Policar; C Sylvain; F Lambert; N Delsuc; C Sandt; P Dumas; M Refregiers; M Plamont; A Vessieres; Z Gueroui; A Dazzi Journal of Biological Inorganic Chemistry, 19 , p. S182-S182, 2014, ISSN: 0949-8257. @article{RN23c,
title = {From IR-Spectromicroscopy using AFM-IR and SR-FTIR to Bimodal Spectromicroscopy using SCoMPIs - Single Core Multimodal Probe for Imaging},
author = {C Policar and C Sylvain and F Lambert and N Delsuc and C Sandt and P Dumas and M Refregiers and M Plamont and A Vessieres and Z Gueroui and A Dazzi},
url = {<Go to ISI>://WOS:000332835300124},
issn = {0949-8257},
year = {2014},
date = {2014-01-01},
journal = {Journal of Biological Inorganic Chemistry},
volume = {19},
pages = {S182-S182},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
2013
|
Toward optimal spatial and spectral quality in widefield infrared spectromicroscopy of IR labelled single cells Article de journal E C Mattson; M Unger; S Clède; F Lambert; C Policar; A Imtiaz; R D'Souza; C J Hirschmugl Analyst, 138 (19), p. 5610–5618, 2013. @article{Mattson:2013,
title = {Toward optimal spatial and spectral quality in widefield infrared spectromicroscopy of IR labelled single cells},
author = {E C Mattson and M Unger and S Cl\`{e}de and F Lambert and C Policar and A Imtiaz and R D'Souza and C J Hirschmugl},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883213711&doi=10.1039%2fc3an00383c&partnerID=40&md5=77ab18447e02b2a40b9a4b70fb8f05b0},
doi = {10.1039/c3an00383c},
year = {2013},
date = {2013-01-01},
journal = {Analyst},
volume = {138},
number = {19},
pages = {5610--5618},
abstract = {Advancements in widefield infrared spectromicroscopy have recently been demonstrated following the commissioning of IRENI (InfraRed ENvironmental Imaging), a Fourier Transform infrared (FTIR) chemical imaging beamline at the Synchrotron Radiation Center. The present study demonstrates the effects of magnification, spatial oversampling, spectral pre-processing and deconvolution, focusing on the intracellular detection and distribution of an exogenous metal tris-carbonyl derivative 1 in a single MDA-MB-231 breast cancer cell. We demonstrate here that spatial oversampling for synchrotron-based infrared imaging is critical to obtain accurate diffraction-limited images at all wavelengths simultaneously. Resolution criteria and results from raw and deconvoluted images for two Schwarzschild objectives (36×, NA 0.5 and 74×, NA 0.65) are compared to each other and to prior reports for raster-scanned, confocal microscopes. The resolution of the imaging data can be improved by deconvolving the instrumental broadening that is determined with the measured PSFs, which is implemented with GPU programming architecture for fast hyperspectral processing. High definition, rapidly acquired, FTIR chemical images of respective spectral signatures of the cell and 1 shows that 1 is localized next to the phosphate- and Amide-rich regions, in agreement with previous infrared and luminescence studies. The infrared image contrast, localization and definition are improved after applying proven spectral pre-processing (principal component analysis based noise reduction and RMie scattering correction algorithms) to individual pixel spectra in the hyperspectral cube. © The Royal Society of Chemistry.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Advancements in widefield infrared spectromicroscopy have recently been demonstrated following the commissioning of IRENI (InfraRed ENvironmental Imaging), a Fourier Transform infrared (FTIR) chemical imaging beamline at the Synchrotron Radiation Center. The present study demonstrates the effects of magnification, spatial oversampling, spectral pre-processing and deconvolution, focusing on the intracellular detection and distribution of an exogenous metal tris-carbonyl derivative 1 in a single MDA-MB-231 breast cancer cell. We demonstrate here that spatial oversampling for synchrotron-based infrared imaging is critical to obtain accurate diffraction-limited images at all wavelengths simultaneously. Resolution criteria and results from raw and deconvoluted images for two Schwarzschild objectives (36×, NA 0.5 and 74×, NA 0.65) are compared to each other and to prior reports for raster-scanned, confocal microscopes. The resolution of the imaging data can be improved by deconvolving the instrumental broadening that is determined with the measured PSFs, which is implemented with GPU programming architecture for fast hyperspectral processing. High definition, rapidly acquired, FTIR chemical images of respective spectral signatures of the cell and 1 shows that 1 is localized next to the phosphate- and Amide-rich regions, in agreement with previous infrared and luminescence studies. The infrared image contrast, localization and definition are improved after applying proven spectral pre-processing (principal component analysis based noise reduction and RMie scattering correction algorithms) to individual pixel spectra in the hyperspectral cube. © The Royal Society of Chemistry. |
Polypyrrole functionalized with new copper complex as platform for His-tag antibody immobilization and direct antigen detection Article de journal S Chebil; A Miodek; V Ambike; H Sauriat-Dorizon; C Policar; H Korri-Youssoufi Sensors and Actuators, B: Chemical, 185 , p. 762–770, 2013. @article{Chebil:2013,
title = {Polypyrrole functionalized with new copper complex as platform for His-tag antibody immobilization and direct antigen detection},
author = {S Chebil and A Miodek and V Ambike and H Sauriat-Dorizon and C Policar and H Korri-Youssoufi},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879243477&doi=10.1016%2fj.snb.2013.05.024&partnerID=40&md5=3d177c3bfb5d34b53cdc0265fd462968},
doi = {10.1016/j.snb.2013.05.024},
year = {2013},
date = {2013-01-01},
journal = {Sensors and Actuators, B: Chemical},
volume = {185},
pages = {762--770},
abstract = {A biomaterial based on a copper complex covalently attached to a polypyrrole backbone was designed for monitoring a glycoprotein, D-dimer, used as a marker of the deep vein thrombosis (DVT) condition. For this purpose a new copper complex has been developed based on the ligand N-(2-hydroxybenzyl)- N′-(6-aminohexyl)-N,N′-bis[2-(N-methylimidazolyl)methyl]ethane-1, 2-diamine (3) that is able to coordinate copper ions through two imidazole, two amine and one phenolato moieties - this coordination sphere will be labeled enPI2. The complex conjugated with a polypyrrole layer allows the His-tag antibody immobilization onto the conducting polymer substrate and immunosensor evaluation. The biomaterial shows a remarkable variation in redox activity of the Cu(II) complex after the D-dimer interaction. The redox activity of the [(enPi2)Cu(II)] complex decreases after the antigen interaction providing a linear response between 0.01 and 500 ng mL-1 with a detection limit of 10 pg mL-1. The chemical structure of copper complex demonstrates the ability to avoid non specific-interaction leading to anti fouling surface. Such biolayer architecture offers high measurement stability over time and the biomaterial could be stocked for several weeks without any modification of the electrochemical properties. © 2013 Elsevier B.V.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A biomaterial based on a copper complex covalently attached to a polypyrrole backbone was designed for monitoring a glycoprotein, D-dimer, used as a marker of the deep vein thrombosis (DVT) condition. For this purpose a new copper complex has been developed based on the ligand N-(2-hydroxybenzyl)- N′-(6-aminohexyl)-N,N′-bis[2-(N-methylimidazolyl)methyl]ethane-1, 2-diamine (3) that is able to coordinate copper ions through two imidazole, two amine and one phenolato moieties - this coordination sphere will be labeled enPI2. The complex conjugated with a polypyrrole layer allows the His-tag antibody immobilization onto the conducting polymer substrate and immunosensor evaluation. The biomaterial shows a remarkable variation in redox activity of the Cu(II) complex after the D-dimer interaction. The redox activity of the [(enPi2)Cu(II)] complex decreases after the antigen interaction providing a linear response between 0.01 and 500 ng mL-1 with a detection limit of 10 pg mL-1. The chemical structure of copper complex demonstrates the ability to avoid non specific-interaction leading to anti fouling surface. Such biolayer architecture offers high measurement stability over time and the biomaterial could be stocked for several weeks without any modification of the electrochemical properties. © 2013 Elsevier B.V. |
Detection of an estrogen derivative in two breast cancer cell lines using a single core multimodal probe for imaging (SCoMPI) imaged by a panel of luminescent and vibrational techniques Article de journal S Clède; F Lambert; C Sandt; S Kascakova; M Unger; E Harté; M -A Plamont; R Saint-Fort; A Deniset-Besseau; Z Gueroui; C Hirschmugl; S Lecomte; A Dazzi; A Vessières; C Policar Analyst, 138 (19), p. 5627–5638, 2013. @article{Clede:2013a,
title = {Detection of an estrogen derivative in two breast cancer cell lines using a single core multimodal probe for imaging (SCoMPI) imaged by a panel of luminescent and vibrational techniques},
author = {S Cl\`{e}de and F Lambert and C Sandt and S Kascakova and M Unger and E Hart\'{e} and M -A Plamont and R Saint-Fort and A Deniset-Besseau and Z Gueroui and C Hirschmugl and S Lecomte and A Dazzi and A Vessi\`{e}res and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883254315&doi=10.1039%2fc3an00807j&partnerID=40&md5=02420b772ef22a07206b5ae31c42dd2e},
doi = {10.1039/c3an00807j},
year = {2013},
date = {2013-01-01},
journal = {Analyst},
volume = {138},
number = {19},
pages = {5627--5638},
abstract = {3-Methoxy-17α-ethynylestradiol or mestranol is a prodrug for ethynylestradiol and the estrogen component of some oral contraceptive formulations. We demonstrate here that a single core multimodal probe for imaging-SCoMPI-can be efficiently grafted onto mestranol allowing its tracking in two breast cancer cell lines, MDA-MB-231 and MCF-7 fixed cells. Correlative imaging studies based on luminescence (synchrotron UV spectromicroscopy, wide field and confocal fluorescence microscopies) and vibrational (AFMIR, synchrotron FTIR spectromicroscopy, synchrotron-based multiple beam FTIR imaging, confocal Raman microspectroscopy) spectroscopies were consistent with one another and showed a Golgi apparatus distribution of the SCoMPI-mestranol conjugate in both cell lines. © The Royal Society of Chemistry.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
3-Methoxy-17α-ethynylestradiol or mestranol is a prodrug for ethynylestradiol and the estrogen component of some oral contraceptive formulations. We demonstrate here that a single core multimodal probe for imaging-SCoMPI-can be efficiently grafted onto mestranol allowing its tracking in two breast cancer cell lines, MDA-MB-231 and MCF-7 fixed cells. Correlative imaging studies based on luminescence (synchrotron UV spectromicroscopy, wide field and confocal fluorescence microscopies) and vibrational (AFMIR, synchrotron FTIR spectromicroscopy, synchrotron-based multiple beam FTIR imaging, confocal Raman microspectroscopy) spectroscopies were consistent with one another and showed a Golgi apparatus distribution of the SCoMPI-mestranol conjugate in both cell lines. © The Royal Society of Chemistry. |
Synchrotron radiation FTIR detection of a metal-carbonyl tamoxifen analog. Correlation with luminescence microscopy to study its subcellular distribution Article de journal S Clède; F Lambert; C Sandt; Z Gueroui; N Delsuc; P Dumas; A Vessières; C Policar Biotechnology Advances, 31 (3), p. 393–395, 2013. @article{Clede:2013,
title = {Synchrotron radiation FTIR detection of a metal-carbonyl tamoxifen analog. Correlation with luminescence microscopy to study its subcellular distribution},
author = {S Cl\`{e}de and F Lambert and C Sandt and Z Gueroui and N Delsuc and P Dumas and A Vessi\`{e}res and C Policar},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875055388&doi=10.1016%2fj.biotechadv.2012.01.023&partnerID=40&md5=064b36e2db4e1260e17d3abc8b07bbd6},
doi = {10.1016/j.biotechadv.2012.01.023},
year = {2013},
date = {2013-01-01},
journal = {Biotechnology Advances},
volume = {31},
number = {3},
pages = {393--395},
abstract = {1,1-Di(4-hydroxyphenyl)-2-cyrhetrenylbut-1-ene 1 is an organometallic conjugate where a [(Cp)Re(CO)3] unit is linked to a hydroxytamoxifen-like structure. Its subcellular nuclear distribution was previously observed in a single cell using the near-field technique AFMIR. We show here that synchrotron radiation FTIR spectromicroscopy (SR-FTIR-SM) enabled the mapping of 1 based on its IR-signature (characteristic bands in the 1850-2200cm-1 range) and pointed out the colocalization of 1 with an area of high amide density. Fluorescence microscopy using DAPI staining performed on the same cells confirmed that this area corresponds to the cell nucleus. © 2012 Elsevier Inc.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
1,1-Di(4-hydroxyphenyl)-2-cyrhetrenylbut-1-ene 1 is an organometallic conjugate where a [(Cp)Re(CO)3] unit is linked to a hydroxytamoxifen-like structure. Its subcellular nuclear distribution was previously observed in a single cell using the near-field technique AFMIR. We show here that synchrotron radiation FTIR spectromicroscopy (SR-FTIR-SM) enabled the mapping of 1 based on its IR-signature (characteristic bands in the 1850-2200cm-1 range) and pointed out the colocalization of 1 with an area of high amide density. Fluorescence microscopy using DAPI staining performed on the same cells confirmed that this area corresponds to the cell nucleus. © 2012 Elsevier Inc. |
