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1.
J Nanobiotechnology ; 17(1): 54, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30992018

RESUMO

BACKGROUND: Nanomaterials that exhibit intrinsic enzyme-like characteristics have shown great promise as potential antibacterial agents. However, many of them exhibit inefficient antibacterial activity and biosafety problems that limit their usefulness. The development of new nanomaterials with good biocompatibility and rapid bactericidal effects is therefore highly desirable. Here, we show a new type of terbium oxide nanoparticles (Tb4O7 NPs) with intrinsic oxidase-like activity for in vitro and in vivo antibacterial application. RESULTS: We find that Tb4O7 NPs can quickly oxidize a series of organic substrates in the absence of hydrogen peroxide. The oxidase-like capacity of Tb4O7 NPs allows these NPs to consume antioxidant biomolecules and generate reactive oxygen species to disable bacteria in vitro. Moreover, the in vivo experiments showed that Tb4O7 NPs are efficacious in wound-healing and are protective of normal tissues. CONCLUSIONS: Our results reveal that Tb4O7 NPs have intrinsic oxidase-like activity and show effective antibacterial ability both in vitro and in vivo. These findings demonstrate that Tb4O7 NPs are effective antibacterial agents and may have a potential application in wound healing.


Assuntos
Antibacterianos/química , Escherichia coli , Nanopartículas Metálicas/química , Óxidos/química , Oxirredutases/química , Staphylococcus aureus , Térbio/química , Cicatrização , Animais , Antibacterianos/farmacologia , Materiais Biocompatíveis/química , Sobrevivência Celular , Escherichia coli/efeitos dos fármacos , Hemólise , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos Endogâmicos BALB C , Óxidos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Térbio/farmacologia
2.
Theranostics ; 6(10): 1611-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27446495

RESUMO

PURPOSE: Radionuclide therapy is increasingly seen as a promising option to target minimal residual disease. Copper-67, scandium-47 and terbium-161 have a medium-energy ß(-) emission which is similar to that of lutetium-177, but offer the advantage of having diagnostic partner isotopes suitable for pretreatment imaging. The aim of this study was to compare the efficacy of (67)Cu, (47)Sc and (161)Tb to irradiate small tumors. METHODS: The absorbed dose deriving from a homogeneous distribution of (67)Cu, (47)Sc or (161)Tb in water-density spheres was calculated with the Monte Carlo code CELLDOSE. The diameters of the spheres ranged from 5 mm to 10 µm, thus simulating micrometastases or single tumor cells. All electron emissions, including ß(-) spectra, Auger and conversion electrons were taken into account. Because these radionuclides differ in electron energy per decay, the simulations were run assuming that 1 MeV was released per µm(3), which would result in a dose of 160 Gy if totally absorbed. RESULTS: The absorbed dose was similar for the three radionuclides in the 5-mm sphere (146-149 Gy), but decreased differently in smaller spheres. In particular, (161)Tb delivered higher doses compared to the other radionuclides. For instance, in the 100-µm sphere, the absorbed dose was 24.1 Gy with (67)Cu, 14.8 Gy with (47)Sc and 44.5 Gy with (161)Tb. Auger and conversion electrons accounted for 71% of (161)Tb dose. The largest dose differences were found in cell-sized spheres. In the 10-µm sphere, the dose delivered by (161)Tb was 4.1 times higher than that from (67)Cu and 8.1 times that from (47)Sc. CONCLUSION: (161)Tb can effectively irradiate small tumors thanks to its decay spectrum that combines medium-energy ß(-) emission and low-energy conversion and Auger electrons. Therefore (161)Tb might be a better candidate than (67)Cu and (47)Sc for treating minimal residual disease in a clinical setting.


Assuntos
Neoplasia Residual/radioterapia , Neoplasias/radioterapia , Radioisótopos/farmacologia , Simulação por Computador , Radioisótopos de Cobre/farmacologia , Escândio/farmacologia , Térbio/farmacologia
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 168: 123-131, 2016 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-27288964

RESUMO

The synthesis of inner transition metal nanoparticles via an ecofriendly route is quite difficult. This study, for the first time, reports synthesis of terbium oxide nanoparticles using fungus, Fusarium oxysporum. The biocompatible terbium oxide nanoparticles (Tb2O3 NPs) were synthesized by incubating Tb4O7 with the biomass of fungus F. oxysporum. Multiple physical characterization techniques, such as UV-visible and photoluminescence spectroscopy, TEM, SAED, and zeta-potential were used to confirm the synthesis, purity, optical and surface characteristics, crystallinity, size, shape, distribution, and stability of the nanoemulsion of Tb2O3 NPs. The Tb2O3 NPs were found to inhibit the propagation of MG-63 and Saos-2 cell-lines (IC50 value of 0.102µg/mL) and remained non-toxic up to a concentration of 0.373µg/mL toward primary osteoblasts. Cell viability decreased in a concentration-dependent manner upon exposure to 10nm Tb2O3 NPs in the concentration range 0.023-0.373µg/mL. Cell toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, and FACS analysis. Morphological examinations of cells revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The level of ROS within the cells-an indicator of oxidative stress was significantly increased. The induction of apoptosis at concentrations ≤IC50 was corroborated by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) staining (DNA damage and nuclear fragmentation). Flow-cytometric studies indicated that the response was dose dependent with a threshold effect.


Assuntos
Neoplasias Ósseas/tratamento farmacológico , Nanopartículas , Osteossarcoma/tratamento farmacológico , Óxidos/farmacologia , Térbio/farmacologia , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fusarium/química , Humanos , Nanopartículas/química , Nanopartículas/ultraestrutura , Nanotecnologia , Osteossarcoma/metabolismo , Osteossarcoma/patologia , Estresse Oxidativo/efeitos dos fármacos , Óxidos/química , Espécies Reativas de Oxigênio/metabolismo , Térbio/química
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 152: 304-10, 2016 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-26232573

RESUMO

The ternary terbium(III) complexes [Tb(HDAP)3⋅biq], [Tb(HDAP)3⋅dmph] and [Tb(HDAP)3⋅bathophen] were prepared by using methoxy substituted hydroxyketone ligand HDAP (2-hydroxy-4,6-dimethoxyacetophenone) and an ancillary ligand 2,2-biquinoline or 5,6-dimethyl-1,10-phenanthroline or bathophenanthroline respectively. The ligand and synthesized complexes were characterised based on elemental analysis, FT-IR and (1)H NMR. Thermal behaviour of the synthesized complexes illustrates the general decomposition patterns of the complexes by thermogravimetric analysis. Photophysical properties such as excitation spectra, emission spectra and luminescence decay curves of the complexes were investigated in detail. The main green emitting peak at 548nm can be attributed to (5)D4→(7)F5 of Tb(3+) ion. Thus, these complexes might be used to make a bright green light-emitting diode for display purpose. In addition the in vitro antibacterial activities of HDAP and its Tb(III) complexes against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and antifungal activities against Candida albicans and Aspergillus niger are reported. The Tb(3+) complexes were found to be more potent antimicrobial agent as compared to the ligand. Among all these complexes, [Tb(HDAP)3⋅bathophen] exhibited excellent antimicrobial activity which proves its potential usefulness as an antimicrobial agent. Furthermore, in vitro antioxidant activity tests were carried out by using DPPH method which indicates that the complexes have considerable antioxidant activity when compared with the standard ascorbic acid.


Assuntos
Acetofenonas/química , Anti-Infecciosos/química , Complexos de Coordenação/química , Fenantrolinas/química , Quinolinas/química , Térbio/química , Acetofenonas/síntese química , Acetofenonas/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/síntese química , Anti-Infecciosos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Antioxidantes/síntese química , Antioxidantes/química , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Fungos/efeitos dos fármacos , Humanos , Ligantes , Micoses/tratamento farmacológico , Nitrogênio/química , Nitrogênio/farmacologia , Fenantrolinas/síntese química , Fenantrolinas/farmacologia , Quinolinas/síntese química , Quinolinas/farmacologia , Térbio/farmacologia
5.
J Biomol Struct Dyn ; 34(2): 414-26, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25994049

RESUMO

Agarose gel electrophoresis, absorption, fluorescence, viscosity, and circular dichroism (CD) have been used in exploring the interaction of terbium(III) complex, [Tb(bpy)2Cl3(OH2)] where bipy is 2,2'-bipyridine, with Fish salmon DNA. Agarose gel electrophoresis assay, along with absorption and fluorescence studies, reveal interaction between the corresponding complex and FS-DNA. Also, the binding constants (Kb) and the Stern-Volmer quenching constants (Ksv) of Tb(III) complex with FS-DNA were determined. The calculated thermodynamic parameters suggested that the binding of mentioned complex to FS-DNA was driven mainly by hydrophobic interactions. A comparative study of this complex with respect to the effect of iodide-induced quenching, ionic strength effect, and ethidium bromide exclusion assay reflects binding of explicit to the FS-DNA primarily in a groove fashion. CD and viscosity data also support the groove binding mode. Furthermore, Tb(III) complex have been simultaneously screened for their antibacterial and antifungal activities.


Assuntos
2,2'-Dipiridil/farmacologia , DNA/metabolismo , Térbio/farmacologia , Absorção de Radiação , Animais , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Sítios de Ligação , Dicroísmo Circular , Clivagem do DNA , Eletroforese em Gel de Ágar , Etídio/química , Etídio/metabolismo , Fungos/efeitos dos fármacos , Cinética , Ligantes , Luminescência , Testes de Sensibilidade Microbiana , Concentração Osmolar , Salmão , Espectrometria de Fluorescência , Temperatura Ambiente , Viscosidade
6.
Nanoscale ; 7(46): 19501-18, 2015 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-26538278

RESUMO

Herein, we report the fabrication of a multifunctional nanoprobe based on highly monodispersed, optically and magnetically active, biocompatible, PEI-functionalized, highly crystalline ß-NaYF4:Gd(3+)/Tb(3+) nanorods as an excellent multi-modal optical/magnetic imaging tool and a pH-triggered intracellular drug delivery nanovehicle. The static and dynamic photoluminescence spectroscopy showed the presence of sharp emission peaks, with long lifetimes (∼3.5 milliseconds), suitable for optical imaging. The static magnetic susceptibility measurements at room temperature showed a strong paramagnetic signal (χ∼ 3.8 × 10(-5) emu g(-1) Oe(-1)). The nuclear magnetic resonance (NMR) measurements showed fair T1 relaxivity (r1 = 1.14 s(-1) mM(-1)) and magnetic resonance imaging gave enhanced T1-weighted MRI images with increased concentrations of ß-NaYF4:Gd(3+)/Tb(3+) making them suitable for simultaneous magnetic resonance imaging. In addition, an anticancer drug, doxorubicin (DOX) was conjugated to the amine-functionalized ß-NaYF4:Gd(3+)/Tb(3+) nanorods via pH-sensitive hydrazone bond linkages enabling them as a pH-triggered, site-specific drug delivery nanovehicle for DOX release inside tumor cells. A comparison between in vitro DOX release studies undertaken in normal physiological (pH 7.4) and acidic (pH 5.0) environments showed an enhanced DOX dissociation (∼80%) at pH 5.0. The multifunctional material was also applied as an optical probe to confirm the conjugation of DOX and to monitor DOX release via a fluorescence resonance energy transfer (FRET) mechanism. The DOX-conjugated ß-NaYF4:Gd(3+)/Tb(3+) nanorods exhibited a cytotoxic effect on MCF-7 breast cancer cells and their uptake by MCF-7 cells was demonstrated using confocal laser scanning microscopy and flow cytometry. The comparative cellular uptakes of free DOX and DOX-conjugated ß-NaYF4:Gd(3+)/Tb(3+) nanorods were studied in tumor microenvironment conditions (pH 6.5) using confocal imaging, which showed an increased uptake of DOX-conjugated ß-NaYF4:Gd(3+)/Tb(3+) nanorods. Thus, DOX-conjugated ß-NaYF4:Gd(3+)/Tb(3+) nanorods combining pH-triggered drug delivery, efficient luminescence and paramagnetic properties are promising for a potential multifunctional platform for cancer therapy, biodetection, and optical and magnetic resonance imaging.


Assuntos
Doxorrubicina , Fluoretos , Gadolínio , Medições Luminescentes/métodos , Imagem por Ressonância Magnética/métodos , Imagem Óptica/métodos , Térbio , Ítrio , Animais , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacologia , Doxorrubicina/química , Doxorrubicina/farmacologia , Feminino , Fluoretos/química , Fluoretos/farmacologia , Gadolínio/química , Gadolínio/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Células MCF-7 , Camundongos , Células NIH 3T3 , Térbio/química , Térbio/farmacologia , Ítrio/química , Ítrio/farmacologia
7.
Dalton Trans ; 44(46): 19844-55, 2015 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-26507987

RESUMO

The europium(III) and terbium(III) complexes, namely [Eu(dpq)(DMF)2(NO3)3] (1), [Eu(dppz)2(NO3)3] (2), [Tb(dpq)(DMF)2Cl3] (3), and [Tb(dppz)(DMF)2Cl3] (4), where dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 1 and 3), dipyrido[3,2-a:2',3'-c]phenazine (dppz in 2 and 4) and N,N'-dimethylformamide (DMF) have been isolated, characterized from their physicochemical data, luminescence studies and their interaction with DNA, serum albumin protein and photo-induced DNA cleavage activity are studied. The X-ray crystal structures of complexes 1-4 show discrete mononuclear Ln(3+)-based structures. The Eu(3+) in [Eu(dpq)(DMF)2(NO3)3] (1) and [Eu(dppz)2(NO3)3] (2) as [Eu(dppz)2(NO3)3]·dppz (2a) adopts a ten-coordinated bicapped dodecahedron structure with a bidentate N,N-donor dpq ligand, two DMF and three NO3(-) anions in 1 and two bidentate N,N-donor dppz ligands and three NO3(-) anions in 2. Complexes 3 and 4 show a seven-coordinated mono-capped octahedron structure where Tb(3+) contains bidentate dpq/dppz ligands, two DMF and three Cl(-) anions. The complexes are highly luminescent in nature indicating efficient photo-excited energy transfer from the dpq/dppz antenna to Ln(3+) to generate long-lived emissive excited states for characteristic f → f transitions. The time-resolved luminescence spectra of complexes 1-4 show typical narrow emission bands attributed to the (5)D0 → (7)F(J) and (5)D4 → (7)F(J) f-f transitions of Eu(3+) and Tb(3+) ions respectively. The number of inner-sphere water molecules (q) was determined from luminescence lifetime measurements in H2O and D2O confirming ligand-exchange reactions with water in solution. The complexes display significant binding propensity to the CT-DNA giving binding constant values in the range of 1.0 × 10(4)-6.1 × 10(4) M(-1) in the order 2, 4 (dppz) > 1, 3 (dpq). DNA binding data suggest DNA groove binding with the partial intercalation nature of the complexes. All the complexes also show binding propensity (K(BSA) ∼ 10(5) M(-1)) to the bovine serum albumin (BSA) protein. The intensity of the time-gated luminescence spectral bands enhances significantly with the increasing DNA concentration in aqueous buffer medium due to displacement of bound water upon interaction with DNA, thus reducing non-radiative quenching through the O-H oscillator. Complexes 1-4 efficiently cleave supercoiled (SC) ds-DNA to its nicked circular (NC) form on exposure to UV-A light of 365 nm via formation of singlet oxygen ((1)O2) and hydroxyl radicals (HO˙) as the reactive oxygen species at micromolar concentrations under physiological conditions.


Assuntos
Complexos de Coordenação/química , Clivagem do DNA/efeitos dos fármacos , Európio/química , Fenazinas/química , Fármacos Fotossensibilizantes/química , Quinoxalinas/química , Térbio/química , Animais , Sítios de Ligação , Bovinos , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , DNA/química , DNA/metabolismo , Európio/farmacologia , Ligantes , Substâncias Luminescentes/química , Substâncias Luminescentes/farmacologia , Modelos Moleculares , Fenazinas/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Quinoxalinas/farmacologia , Soroalbumina Bovina/química , Soroalbumina Bovina/metabolismo , Térbio/farmacologia , Raios Ultravioleta
8.
Int J Mol Sci ; 16(7): 16642-54, 2015 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-26204836

RESUMO

This article describes the genetically encoded caspase-3 FRET-sensor based on the terbium-binding peptide, cleavable linker with caspase-3 recognition site, and red fluorescent protein TagRFP. The engineered construction performs two induction-resonance energy transfer processes: from tryptophan of the terbium-binding peptide to Tb(3+) and from sensitized Tb(3+) to acceptor--the chromophore of TagRFP. Long-lived terbium-sensitized emission (microseconds), pulse excitation source, and time-resolved detection were utilized to eliminate directly excited TagRFP fluorescence and background cellular autofluorescence, which lasts a fraction of nanosecond, and thus to improve sensitivity of analyses. Furthermore the technique facilitates selective detection of fluorescence, induced by uncleaved acceptor emission. For the first time it was shown that fluorescence resonance energy transfer between sensitized terbium and TagRFP in the engineered construction can be studied via detection of microsecond TagRFP fluorescence intensities. The lifetime and distance distribution between donor and acceptor were calculated using molecular dynamics simulation. Using this data, quantum yield of terbium ions with binding peptide was estimated.


Assuntos
Técnicas Biossensoriais/métodos , Caspase 3/química , Transferência Ressonante de Energia de Fluorescência/métodos , Proteínas Luminescentes/química , Térbio/farmacologia , Sequência de Aminoácidos , Caspase 3/genética , Proteínas Luminescentes/genética , Metaloproteínas/química , Metaloproteínas/metabolismo , Simulação de Dinâmica Molecular , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/genética , Peptídeos/metabolismo , Ligação Proteica , Térbio/química
9.
Nanoscale ; 7(36): 14829-37, 2015 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-26205500

RESUMO

Multimodal and multifunctional contrast agents receive enormous attention in the biomedical imaging field. Such contrast agents are routinely prepared by the incorporation of organic molecules and inorganic nanoparticles (NPs) into host materials such as gold NPs, silica NPs, polymer NPs, and liposomes. Despite their non-cytotoxic nature, the large size of these NPs limits the in vivo distribution and clearance and inflames complex pharmacokinetics, which hinder the regulatory approval for clinical applications. Herein, we report a unique method that combines magnetic resonance imaging (MRI) and fluorescence imaging modalities together in nanoscale entities by the simple, direct and stable conjugation of novel biotinylated coordination complexes of gadolinium(III) to CdSe/ZnS quantum dots (QD) and terbium(III) to super paramagnetic iron oxide NPs (SPION) but without any host material. Subsequently, we evaluate the potentials of such lanthanide-speckled fluorescent-magnetic NPs for bioimaging at single-molecule, cell and in vivo levels. The simple preparation and small size make such fluorescent-magnetic NPs promising contrast agents for biomedical imaging.


Assuntos
Meios de Contraste , Compostos Férricos , Imagem Óptica , Pontos Quânticos/química , Térbio , Animais , Linhagem Celular , Meios de Contraste/química , Meios de Contraste/farmacologia , Compostos Férricos/química , Compostos Férricos/farmacologia , Camundongos , Térbio/química , Térbio/farmacologia
10.
Biol Trace Elem Res ; 164(1): 122-9, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25534291

RESUMO

Rare earth elements, especially terbium (Tb), are high-valence heavy metal elements that accumulate in the environment, and they show toxic effects on plants. Signaling molecules regulate many physiological and biochemical processes in plants. How rare earth elements affect signaling molecules remains largely unknown. In the present study, the effects of Tb(3+) on some extracellular and intracellular signaling molecules (gibberellic acid, abscisic acid, auxin, H2O2, and Ca(2+)) in horseradish leaves were investigated by using high-performance liquid chromatography, X-ray energy spectrometry, and transmission electron microscopy, and Tb(3+) was sprayed on the surface of leaves. Tb(3+) treatment decreased the auxin and gibberellic acid contents and increased the abscisic acid content. These changes in the contents of phytohormones (gibberellic acid, abscisic acid, and auxin) triggered excessive production of intracellular H2O2. Consequently, the increase in H2O2 content stimulated the influx of extracellular Ca(2+) and the release of Ca(2+) from Ca(2+) stores, leading to Ca(2+) overload and the resulting inhibition of physiological and biochemical processes. The effects outlined above were more evident with increasing the concentration of Tb(3+) sprayed on horseradish leaves. Our data provide a possible underlying mechanism of Tb(3+) action on plants.


Assuntos
Armoracia/efeitos dos fármacos , Armoracia/metabolismo , Térbio/farmacologia , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Peróxido de Hidrogênio/metabolismo , Ácidos Indolacéticos/metabolismo
11.
Dalton Trans ; 43(32): 12321-8, 2014 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-24985564

RESUMO

Multi-modal imaging based on multifunctional nanoparticles provides deep, non-invasive and highly sensitive imaging and is a promising alternative approach that can improve the sensitivity of early cancer diagnosis. In this study, two nanoparticles, TbPO4:Ce(3+) and TbPO4:Ce(3+)@TbPO4:Gd(3+), were synthesized via the citric-acid-mediated hydrothermal route, and then systematically characterized by means of microstructure, photoluminescence, magnetic resonance imaging (MRI), biocompatibility, and bioimaging. The results of energy dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) line scans indicated that TbPO4:Gd(3+) nanoshells about 5 nm in thickness were successfully coated on the TbPO4:Ce(3+) nanocores. X-ray diffraction (XRD) and Fourier transforms of high-resolution transmission electron microscopy (TEM) images indicated that the core-shell nanocomposites had a single crystal structure. The photoluminescence of the TbPO4:Ce(3+)@TbPO4:Gd(3+) and TbPO4:Ce(3+) nanoparticles was greatly intensified by 200 times and 100 times, respectively, compared with pure TbPO4 nanoparticles. In vitro cytotoxicity tests based on the methyl thiazolyl tetrazolium (MTT) assay demonstrated that the monodispersed nanoparticles of TbPO4:Ce(3+)@TbPO4:Gd(3+) had low toxicity. The intracellular luminescence of the nanoparticles after being internalized by HeLa cells was also observed using confocal fluorescence microscopes. MRI showed that the nanoshells of Gd-doped TbPO4 possessed a longitudinal relaxivity of 4.067 s(-1) mM(-1), which is comparable to that of the commercial MRI contrast Gd-TDPA. As a result, the core-shell structured TbPO4:Ce(3+)@TbPO4:Gd(3+) nanoparticles can potentially serve as multifunctional nanoprobes for both optical biolabels and MRI contrast agents.


Assuntos
Cério/química , Gadolínio/química , Nanocompostos/química , Fosfatos/química , Térbio/química , Sobrevivência Celular/efeitos dos fármacos , Cério/farmacologia , Gadolínio/farmacologia , Células HeLa , Humanos , Luminescência , Imagem por Ressonância Magnética , Microscopia Eletrônica de Transmissão , Nanocompostos/ultraestrutura , Fosfatos/farmacologia , Espectrometria por Raios X , Térbio/farmacologia , Difração de Raios X
12.
Biol Trace Elem Res ; 161(1): 130-5, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25055927

RESUMO

The pollution of the environment by rare earth elements (REEs) causes deleterious effects on plants. Peroxidase plays important roles in plant response to various environmental stresses. Here, to further understand the overall roles of peroxidase in response to REE stress, the effects of the REE terbium ion (Tb(3+)) on the peroxidase activity and H2O2 and lignin contents in the leaves and roots of horseradish during different growth stages were simultaneously investigated. The results showed that after 24 and 48 h of Tb(3+) treatment, the peroxidase activity in horseradish leaves decreased, while the H2O2 and lignin contents increased. After a long-term (8 and 16 days) treatment with Tb(3+), these effects were also observed in the roots. The analysis of the changes in peroxidase activity and H2O2 and lignin contents revealed that peroxidase plays important roles in not only reactive oxygen species scavenging but also cell wall lignification in horseradish under Tb(3+) stress. These roles were closely related to the dose of Tb(3+), duration of stress, and growth stages of horseradish.


Assuntos
Armoracia/efeitos dos fármacos , Peroxidase do Rábano Silvestre/metabolismo , Proteínas de Plantas/metabolismo , Térbio/farmacologia , Armoracia/enzimologia , Armoracia/metabolismo , Relação Dose-Resposta a Droga , Peróxido de Hidrogênio/metabolismo , Lignina/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/metabolismo , Estresse Fisiológico , Fatores de Tempo
13.
Inorg Chem ; 53(12): 6013-21, 2014 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-24901440

RESUMO

A systematic study of the effect of hydrophobicity and charge on the cell viability and cell association of lanthanide metal complexes is presented. The terbium luminescent probes feature a macrocyclic polyaminocarboxylate ligand (DOTA) in which the hydrophobicity of the antenna and that of the carboxyamide pendant arms are independently varied. Three sensitizing antennas were investigated in terms of their function in vitro: 2-methoxyisophthalamide (IAM(OMe)), 2-hydroxyisophthalamide (IAM), and 6-methylphenanthridine (Phen). Of these complexes, Tb-DOTA-IAM exhibited the highest quantum yield, although the higher cell viability and more facile synthesis of the structurally related Tb-DOTA-IAM(OMe) platform renders it more attractive. Further modification of this latter core structure with carboxyamide arms featuring hydrophobic benzyl, hexyl, and trifluoro groups as well as hydrophilic amino acid based moieties generated a family of complexes that exhibit high cell viability (ED50 > 300 µM) regardless of the lipophilicity or the overall complex charge. Only the hexyl-substituted complex reduced cell viability to 60% in the presence of 100 µM complex. Additionally, cellular association was investigated by ICP-MS and fluorescence microscopy. Surprisingly, the hydrophobic moieties did not increase cell association in comparison to the hydrophilic amino acid derivatives. It is thus postulated that the hydrophilic nature of the 2-methoxyisophthalamide antenna (IAM(OMe)) disfavors the cellular association of these complexes. As such, responsive luminescent probes based on this scaffold would be appropriate for the detection of extracellular species.


Assuntos
Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/química , Compostos Heterocíclicos com 1 Anel/química , Substâncias Luminescentes/química , Térbio/química , Amidas/química , Amidas/farmacologia , Animais , Linhagem Celular , Complexos de Coordenação/farmacologia , Células HeLa , Compostos Heterocíclicos com 1 Anel/farmacologia , Humanos , Interações Hidrofóbicas e Hidrofílicas , Substâncias Luminescentes/farmacologia , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Fenantridinas/química , Fenantridinas/farmacologia , Ácidos Ftálicos/química , Ácidos Ftálicos/farmacologia , Ratos , Térbio/farmacologia
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 131: 388-97, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24835942

RESUMO

The complexes of Sm(III) and Tb(III) with 2-aminobenzoic acid (anthranilic acid, AA) and 2-amino-5-chlorobenzoic acid (5-chloroanthranilic acid, AACl) were synthesized and characterized based on elemental analysis, IR and mass spectroscopy. The data are in accordance with 1:3 [Metal]:[Ligand] ratio. On the basis of the IR analysis, it was found that the metals were coordinated to bidentate anthranilic acid via the ionised oxygen of the carboxylate group and to the nitrogen of amino group. While in 5-chloroanthranilic acid, the metals were coordinated oxidatively to the bidentate carboxylate group without bonding to amino group; accordingly, a chlorine-affected coordination and reactivity-diversity was emphasized. Thermal analyses (TGA) and biological activity of the complexes were also investigated. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using SDDALL basis set. Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, dipole moment and orientation have been performed and discussed.


Assuntos
Anti-Infecciosos/química , Complexos de Coordenação/química , Samário/química , Térbio/química , ortoaminobenzoatos/química , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Complexos de Coordenação/farmacologia , Fungos/efeitos dos fármacos , Halogenação , Humanos , Modelos Moleculares , Micoses/tratamento farmacológico , Teoria Quântica , Samário/farmacologia , Térbio/farmacologia , ortoaminobenzoatos/farmacologia
15.
J Biol Inorg Chem ; 19(6): 879-91, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24585101

RESUMO

With its special physical and chemical properties, terbium has been widely used, which has inevitably increased the chance of human exposure to terbium-based compounds. It was reported that terbium mainly deposited in bone after introduction into the human body. Although some studies revealed the effects of terbium on bone cell lines, there have been few reports about the potential effect of terbium on adhesion and differentiation of mesenchymal stem cells (MSCs). In this study, we investigated the effects of terbium on the adhesion and osteogenic and adipogenic differentiation of MSCs and the associated molecular mechanisms. Our data reveal that terbium promoted the osteogenic differentiation in a time-dependent manner and conversely inhibited the adipogenic differentiation of MSCs. Meanwhile, the cell-cell or cell-matrix interaction was enhanced by activating adherent-related key factors, which were evaluated by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Real-time RT-PCR and Western blot analysis were also performed to further detect osteogenic and adipogenic biomarkers of MSCs. The regulation of terbium on differentiation of MSCs led to the interaction between the transforming growth factor ß/bone morphogenetic protein and peroxisome-proliferator-activated receptor γ (PPARγ) signaling pathways, resulting in upregulation of the osteogenic master transcription factors, such as Runt-related transcription factor 2, bone morphogenetic protein 2, collagen I, alkaline phosphatase, and osteocalcin, and downregulation of the adipogenic master transcription factors, such as PPARγ2. The results provide novel evidence to elucidate the mechanisms of bone metabolism by terbium and may be helpful for more rational application of terbium-based compounds in the future.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Térbio/farmacologia , Fator de Crescimento Transformador beta/metabolismo , Adipogenia/efeitos dos fármacos , Adipogenia/genética , Animais , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos , Osteogênese/genética , PPAR gama/antagonistas & inibidores , PPAR gama/metabolismo
16.
Biol Trace Elem Res ; 157(2): 183-8, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24420373

RESUMO

Rare earth elements (REEs) entering plant cells can directly interact with peroxidase in plants, which is the structural basis for the decrease in the activity of peroxidase. Different cellular compartments have different pH values. However, little information is available regarding the direct interaction between REEs and peroxidase in plants at different pH values. Here, we investigated the charge distribution on the surface of horseradish peroxidase (HRP) molecule as well as the interaction of terbium ion (Tb(3+), one type of REEs) and HRP at different pH values. Using the molecular dynamics simulation, we found that when the pH value was from 4.0 to 8.0, a large amount of negative charges were intensively distributed on the surface of HRP molecule, and thus, we speculated that Tb(3+) with positive charges might directly interact with HRP at pH 4.0-8.0. Subsequently, using ultraviolet-visible spectroscopy, we demonstrated that Tb(3+) could directly interact with HRP in the simulated physiological solution at pH 7.0 and did not interact with HRP in other solutions at pH 5.0, pH 6.0 and pH 8.0. In conclusion, we showed that the direct interaction between Tb(3+) and HRP molecule depended on the pH value of cellular compartments.


Assuntos
Armoracia/efeitos dos fármacos , Peroxidase do Rábano Silvestre/metabolismo , Térbio/farmacologia , Armoracia/enzimologia , Eletroquímica , Concentração de Íons de Hidrogênio , Simulação de Dinâmica Molecular , Espectrofotometria Ultravioleta
17.
Molecules ; 18(5): 5005-31, 2013 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-23629756

RESUMO

The folate receptor (FR) is expressed in many tumor types, among those ovarian and lung cancer. Due to the high FR affinity of folic acid, it has been used for targeting of FR-positive tumors, allowing specific delivery of attached probes to the malignant tissue. Therefore, nuclear imaging of FR-positive cancer is of clinical interest for selecting patients who could benefit from innovative therapy concepts based on FR-targeting. Positron emission computed tomography (PET) has become an established technique in clinical routine because it provides an increased spatial resolution and higher sensitivity compared to single photon emission computed tomography (SPECT). Therefore, it is of critical importance to develop folate radiotracers suitable for PET imaging. This review article updates on the design, preparation and pre-clinical investigation of folate derivatives for radiolabeling with radioisotopes for PET. Among those the most relevant radionuclides so far are fluorine-18 (t(1/2): 110 min, E(av) ß⁺: 250 keV) and gallium-68 (t(1/2): 68 min, E(av) ß⁺: 830 keV). Recent results obtained with new PET isotopes such as terbium-152 (t(1/2): 17.5 h, Eß⁺: 470 keV) or scandium-44 (t(1/2): 3.97 h, (Eav) ß⁺: 632 keV) are also presented and discussed. Current endeavors for clinical implementation of PET agents open new perspectives for identification of FR-positive malignancies in patients.


Assuntos
Ácido Fólico , Neoplasias Experimentais/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Animais , Radioisótopos de Flúor/química , Radioisótopos de Flúor/farmacologia , Receptor 1 de Folato/agonistas , Receptor 1 de Folato/metabolismo , Ácido Fólico/síntese química , Ácido Fólico/química , Ácido Fólico/farmacologia , Isótopos de Gálio/química , Isótopos de Gálio/farmacologia , Camundongos , Proteínas de Neoplasias/agonistas , Proteínas de Neoplasias/metabolismo , Neoplasias Experimentais/metabolismo , Radiografia , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/farmacologia , Térbio/química , Térbio/farmacologia
18.
Microcirculation ; 19(6): 477-84, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22435898

RESUMO

OBJECTIVE: We examined the three-dimensional organization of the endothelial vesicular system with TEM tomography of semi-thick sections. MATERIALS AND METHODS: Mouse abdominal muscle capillaries were perfused with terbium to label vesicular compartments open to the luminal surface. The tissue was prepared for TEM and semi-thick (250 nm) sections were cut. Dual axis tilt series, collected from +60° to -60° at 1° increments, were acquired in regions of labeled abluminal caveolae. These tomograms were reconstructed and analyzed to reveal three-dimensional vesicular associations not evident in thin sections. RESULTS: Reconstructed tomograms revealed free vesicles, both labeled and unlabeled, in the endothelial cytoplasm as well as transendothelial channels that spanned the luminal and abluminal membranes. A large membranous compartment connecting the luminal and abluminal surfaces was also present. Computer modeling of tomographic data and video animations provided three-dimensional perspectives to these structures. CONCLUSIONS: Uncertainties associated with other three-dimensional methods to study the capillary wall are remedied by tomographic analysis of semi-thick sections. Transendothelial channels of fused vesicles and free cytoplasmic vesicles give credence to their role as large pores in the transport of solutes across the walls of continuous capillaries.


Assuntos
Capilares/ultraestrutura , Vesículas Citoplasmáticas/ultraestrutura , Tomografia com Microscopia Eletrônica , Endotélio Vascular/ultraestrutura , Imagem Tridimensional , Animais , Camundongos , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/ultraestrutura , Térbio/farmacologia
19.
Appl Environ Microbiol ; 77(15): 5536-9, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21685163

RESUMO

Release of dipicolinic acid (DPA) and its fluorescence with terbium (Tb(3+)) allow rapid measurement of the germination and viability of spores of Bacillus and Clostridium species. However, germination of coat-deficient Bacillus spores was strongly inhibited by Tb(3+) and some other multivalent cations. Tb(3+) also inhibited germination of coat-deficient Clostridium perfringens spores.


Assuntos
Bacillus/efeitos dos fármacos , Clostridium/efeitos dos fármacos , Esporos Bacterianos/efeitos dos fármacos , Térbio/farmacologia , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Proteínas de Bactérias/metabolismo , Cátions , Clostridium/crescimento & desenvolvimento , Clostridium/metabolismo , Fluorescência , Viabilidade Microbiana , Ácidos Picolínicos , Esporos Bacterianos/crescimento & desenvolvimento , Esporos Bacterianos/metabolismo , Térbio/química , Térbio/metabolismo
20.
Nanoscale ; 3(3): 1263-9, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21135975

RESUMO

Luminescent TbPO4 nanoparticles were synthesized via a citric-acid-mediated hydrothermal route. Eu3+ doping of TbPO4 enables an efficient Tb3+-to-Eu3+ energy transfer, leading to a four-fold increase of the absolute emission quantum yield (QY), compared to that of undoped TbPO4. To check the potential of biological use, we conducted in vitro biological experiments on human cervical carcinoma HeLa cells incubated with TbPO4:Eu nanoparticles. TbPO4:Eu nanoparticles can be successfully internalized into the cells, and they show bright intracellular luminescence and very low cytotoxicity. Photoluminescence intensity dependence upon time demonstrates that Eu3+-doped TbPO4 nanoparticles are highly resistant to photobleaching. Our present work represents a demonstration of the use of rare-earth-based nanocrystals as a biological labeling agent because they combine several advantages including high emission quantum yield, long luminescence lifetime, low cytotoxicity and high photostability.


Assuntos
Apoptose/efeitos dos fármacos , Európio/farmacologia , Medições Luminescentes/métodos , Nanoestruturas/administração & dosagem , Nanoestruturas/ultraestrutura , Fosfatos/farmacologia , Térbio/farmacologia , Európio/química , Células HeLa , Humanos , Teste de Materiais , Tamanho da Partícula , Fosfatos/química , Térbio/química
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