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1.
Langmuir ; 37(8): 2740-2748, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33586439

RESUMO

Hydrophilic fullerene derivatives get notable performance in various biological applications, especially in cancer therapy and antioxidation. The biological behaviors of functional fullerenes are much dependent on their surface physicochemical properties. The excellent reactive oxygen species-scavenging capabilities of functional fullerenes promote their outstanding performances in inhibiting pathological symptoms associated with oxidative stress, including neurodegenerative diseases, cardiovascular diseases, acute and chronic kidney disease, and diabetes. Herein, fullerene derivatives with reversed surface charges in aqueous solutions are prepared: cationic C60-EDA and anionic C60-(EDA-EA). Under the driving force of membrane potential (negative inside) in the cell and mitochondria, C60-EDA is much rapidly taken in by cells and transported into mitochondria compared with C60-(EDA-EA) that is enriched in lysosomes. With high cellular uptake and mitochondrial enrichment, C60-EDA exhibits stronger antioxidation capabilities in vitro than C60-(EDA-EA), indicating its better performance in the therapy of oxidation-induced diseases. It is revealed that the cellular uptake rate, subcellular location, and intracellular antioxidation behavior of fullerene derivatives are primarily mediated by their surface charges, providing new strategies for the design of fullerene drugs and their biological applications.


Assuntos
Fulerenos , Antioxidantes/farmacologia , Organelas , Estresse Oxidativo , Espécies Reativas de Oxigênio
2.
Angew Chem Int Ed Engl ; 60(28): 15225-15229, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-33855792

RESUMO

Inhaled gene therapy poses a unique potential of curing chronic lung diseases, which are currently managed primarily by symptomatic treatments. However, it has been challenging to achieve therapeutically relevant gene transfer efficacy in the lung due to the presence of numerous biological delivery barriers. Here, we introduce a simple approach that overcomes both extracellular and cellular barriers to enhance gene transfer efficacy in the lung in vivo. We endowed tetra(piperazino)fullerene epoxide (TPFE)-based nanoparticles with non-adhesive surface polyethylene glycol (PEG) coatings, thereby enabling the nanoparticles to cross the airway mucus gel layer and avoid phagocytic uptake by alveolar macrophages. In parallel, we utilized a hypotonic vehicle to facilitate endocytic uptake of the PEGylated nanoparticles by lung parenchymal cells via the osmotically driven regulatory volume decrease (RVD) mechanism. We demonstrate that this two-pronged delivery strategy provides safe, wide-spread and high-level transgene expression in the lungs of both healthy mice and mice with chronic lung diseases characterized by reinforced delivery barriers.


Assuntos
Compostos de Epóxi/química , Fulerenos/química , Técnicas de Transferência de Genes , Pneumopatias/terapia , Nanopartículas/química , Doença Crônica , Humanos , Pneumopatias/metabolismo
3.
J Am Chem Soc ; 140(24): 7373-7376, 2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29799737

RESUMO

Reactive oxygen species (ROS) and glutathione (GSH) dual responsive nanoparticulate drug delivery systems (nano-DDSs) hold great promise to improve the therapeutic efficacy and alleviate the side effects of chemo drugs in cancer theranosis. Herein, hydrogen peroxide (H2O2) and GSH dual responsive thioketal nanoparticle (TKN) was rationally designed for paclitaxel (PTX) delivery. Compared to other stimuli-sensitive nano-DDSs, this dual responsive DDS is not only sensitive to biologically relevant H2O2 and GSH for on-demand drug release but also biodegradable into biocompatible byproducts after fulfilling its delivering task. Considering the heterogeneous redox potential gradient, the PTX loaded TKNs (PTX-TKNs) might first respond to the extracellular ROS and then to the intracellular GSH, achieving a programmable release of PTX at the tumor site. The selective toxicity of PTX-TKNs to tumor cells with high levels of ROS and GSH was verified both in vitro and in vivo.


Assuntos
Antineoplásicos/uso terapêutico , Portadores de Fármacos/química , Nanopartículas/química , Paclitaxel/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Plásticos Biodegradáveis/síntese química , Plásticos Biodegradáveis/química , Plásticos Biodegradáveis/toxicidade , Células CHO , Linhagem Celular Tumoral , Cricetulus , Portadores de Fármacos/síntese química , Portadores de Fármacos/toxicidade , Liberação Controlada de Fármacos , Glutationa/química , Química Verde/métodos , Humanos , Peróxido de Hidrogênio/química , Masculino , Camundongos , Nanopartículas/toxicidade , Paclitaxel/química , Paclitaxel/farmacologia , Polímeros/síntese química , Polímeros/química , Polímeros/toxicidade , Sulfetos/síntese química , Sulfetos/química , Sulfetos/toxicidade , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Nanomedicine ; 14(4): 1361-1369, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29649591

RESUMO

Pulmonary fibrosis has become a fatal disease for its high incidence and few effective drugs available in clinic. In this study, gadofullerenol (GF-OH) and [70] fullerenol (C70-OH) nanoparticles (NPs) prepared by a one-pot reaction were designed as nanomedicines to treat this fatal disease. It was revealed that the inhalation of gadofullerenols and [70] fullerenols substantially alleviates the collagen deposition induced by acute lung injury. Based on detailed studies of oxidative stress parameters and transforming growth factor-ß1 (TGF-ß1), we demonstrated they owned the antioxidant and anti-inflammatory functions for the modulation of ROS-mediated inflammation process. Thus the therapeutic effect may be associated with synergistic mechanism of scavenging free radicals and indirectly modulating TGF-ß1 expression. Moreover, GF-OH NPs were observed to show the superiority to C70-OH NPs both in vitro and in vivo due to the structural distinction. These results suggest the inhalable fullerenols are highly potential for clinical therapy of pulmonary fibrosis.


Assuntos
Fulerenos/administração & dosagem , Fulerenos/uso terapêutico , Fibrose Pulmonar/tratamento farmacológico , Animais , Antioxidantes/metabolismo , Bleomicina/toxicidade , Linhagem Celular , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos , Fibrose Pulmonar/induzido quimicamente , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
5.
Chemistry ; 22(28): 9676-86, 2016 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-27249665

RESUMO

Construction of Gd(III) photosensitizers is important for designing theranostic agents owing to the unique properties arising from seven unpaired f electrons of the Gd(3+) ion. Combining these with the advantages of porpholactones with tunable NIR absorption, we herein report the synthesis of Gd(III) complexes Gd-1-4 (1, porphyrin; 2, porpholactone; 3 and 4, cis- and trans-porphodilactone, respectively) and investigated their function as singlet oxygen ((1) O2 ) photosensitizers. These Gd complexes displayed (1) O2 quantum yields (ΦΔ s) from 0.64-0.99 with the order Gd-1

6.
J Nanosci Nanotechnol ; 16(3): 2504-8, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27455662

RESUMO

A homogeneous C60 tri-diethyl malonate membrane was fabricated by a facile electro-spinning method. Comprehensive characterizations of its assembling structure, such as SEM, TEM, TGA, UV-vis, and FTIR, were carried out. Different fullerene derivatives show different assembling characters during the electrospining process. Notably, C60 tri-diethyl malonate with close-knite structures can form a stable structure after removing the assistant polymer of PVP. The antibacterial experiments of C60 tri-diethyl malonate membrane were performed, and the results revealed that this membrane owns excellent antibacterial activity.


Assuntos
Antibacterianos/farmacologia , Fulerenos/química , Malonatos/química , Membranas Artificiais , Antibacterianos/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
7.
Chemistry ; 20(20): 6126-30, 2014 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-24700619

RESUMO

Porous Mn2O3 nanoplates were prepared by a facile polyol solution method combined with a simple post-annealing process. The porous Mn2O3 nanoplates were characterized by XRD, field-emission SEM, high-resolution TEM, and N2 adsorption/desorption isotherm measurements. The formation process for the Mn2O3 nanoplates was proposed as a morphology-conserved transformation strategy. These porous nanoplates exhibited improved electrochemical performance with excellent cycling stability and good rate capability when applied as anode materials in lithium ion batteries.

8.
Analyst ; 139(8): 1993-9, 2014 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-24600682

RESUMO

Direct selective determination of free heme in the cerebral system is of great significance due to the crucial roles of free heme in physiological and pathological processes. In this work, a G-quadruplex DNAzymes-induced highly sensitive and selective colorimetric sensing of free heme in rat brain is established. Initially, the conformation of an 18-base G-rich DNA sequence, PS2.M (5'-GTGGGTAGGGCGGGTTGG-3'), in the presence of K(+), changes from a random coil to a "parallel" G-quadruplex structure, which can bind free heme in the cerebral system with high affinity through π-π stacking. The resulted heme/G-quadruplex complex exhibits high peroxidase-like activity, which can be used to catalyze the oxidation of colorless ABTS(2-) to green ABTS˙(-) by H2O2. The concentration of heme can be evaluated by the naked eye and determined by UV-vis spectroscopy. The signal output showed a linear relationship for heme within the concentration range from 1 to 120 nM with a detection limit of 0.637 nM. The assay demonstrated here was highly selective and free from the interference of physiologically important species such as dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbate acid (AA), cysteine, uric acid (UA), glucose and lactate in the cerebral system. The basal dialysate level of free heme in the microdialysate from the striatum of adult male Sprague-Dawley rats was determined to be 32.8 ± 19.5 nM (n = 3). The analytic protocol possesses many advantages, including theoretical simplicity, low-cost technical and instrumental demands, and responsible detection of heme in rat brain microdialysate.


Assuntos
Encéfalo/metabolismo , Colorimetria , DNA Catalítico/metabolismo , Quadruplex G , Animais , Sequência de Bases , Dicroísmo Circular , Limite de Detecção , Masculino , Microdiálise , Ratos , Ratos Sprague-Dawley , Espectrofotometria Ultravioleta
9.
Anal Chem ; 85(9): 4729-34, 2013 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-23574540

RESUMO

The quantitative analysis by matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) is a challenge due to the poor reproducibility originating from the heterogeneity of the matrix-analyte crystals. Polystyrene (PS) colloidal spheres have superior monodispersed property and can self-assemble to form photonic crystals. With the assistance of PS spheres, a uniform matrix-analyte cocrystal was constructed for the quantitative analysis of plasma lysophosphatidylcholines (LPCs). The matrix and the solvent in MALDI MS analysis were optimized, and the reproducibility and the accuracy were investigated in detail. This is the first report about the very simple method of PS spheres-assisted MALDI MS for quantitative analysis, where it is believed that this approach will greatly expand the applications of MALDI MS.


Assuntos
Adenoma/sangue , Neoplasias Colorretais/sangue , Lisofosfatidilcolinas/sangue , Poliestirenos/química , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
10.
Chemistry ; 19(43): 14675-81, 2013 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-24027072

RESUMO

The development of novel nanomaterials for the diagnosis and/or treatment of human diseases has become an important issue. In this work, a multifunctional theranostic agent was designed by covalently binding hydroxyl- and amino-bearing C60 derivatives (C60 O∼10 (OH)∼16 (NH2 )∼6 (NO2 )∼6 ⋅24 H2 O) with gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) to yield C60 O∼10 (OH)∼16 (NH2 )∼6 (NO2 )∼6 ⋅24 H2 O/(Gd-DTPA)3 (DF1 Gd3 ). The obtained DF1 Gd3 shows more than fourfold contrast improvement over commercial Gd-DTPA along with multiwavelength fluorescent emission for dual-modality diagnosis. An inner-ear magnetic resonance imaging (MRI) study was designed as a model of biological barriers, including the blood/brain barrier (BBB) for DF1 Gd3 to investigate its in vivo behavior. This revealed that the fabricated contrast agent dramatically increases the local contrast but can not cross the middle ear/inner ear barrier and endolymph/perilymph barrier in the inner ear, and thus it is also BBB-prohibited in normal individuals. In vivo biodistribution studies suggested that 1) DF1 Gd3 could circulate in vessels for a relatively long time and is mainly eliminated through liver and kidney, 2) DF1 Gd3 may potentially function as a liver-specific MRI contrast agent. Interestingly, DF1 Gd3 also shows an excellent quenching effect on hydroxyl radicals, as revealed by the DMPO spin trap/ESR method. The combination of enhanced MRI/FL imaging and local treatment of lesions is unique to DF1 Gd3 and potentiates the medical paradigm of "detect and treat/prevent" in combating human diseases related to reactive oxygen.


Assuntos
Meios de Contraste/química , Nanoestruturas/química , Animais , Barreira Hematoencefálica/química , Barreira Hematoencefálica/metabolismo , Meios de Contraste/farmacocinética , Complexos de Coordenação/química , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/metabolismo , Fulerenos/química , Gadolínio/química , Humanos , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Camundongos , Radiografia , Ratos , Espécies Reativas de Oxigênio/química , Distribuição Tecidual
11.
Environ Sci Technol ; 47(13): 7490-8, 2013 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-23721301

RESUMO

In this work, we have investigated the change of cell wall for the tobacco plant cell (Nicotiana tobacum L. cv. Bright Yellow) under the repression of water-soluble carboxyfullerenes (C70(C(COOH)2)(2-4)). The adsorption of C70(C(COOH)2)(2-4) on cell wall led to the disruption of cell wall and membrane, and consequently, cell growth inhibition. Results from atomic force microscopy (AFM) force measurement and confocal imaging revealed an increase of the glycosyl residue on the cell wall of carboxyfullerene-treated cells, with a time- and dose-dependent manner, and accompanied by the elevated reactive oxygen species (ROS). Moreover, the stimulation-sensitive alteration of glycosyl residue and ROS was demonstrated, which suggested a possible protection strategy for the plant cells under fullerene repression. This study provides the first direct evidence on the change of plant cell wall composition under the repression of fullerene and is the first successful application of AFM ligand-receptor binding force measurement to the living plant cell. The new information present here would help to a better understanding and assessment of the biological effect of fullerenes on plant.


Assuntos
Ácidos Carboxílicos/farmacologia , Parede Celular/efeitos dos fármacos , Fulerenos/farmacologia , Nicotiana/citologia , Acetilglucosamina/metabolismo , Adsorção , Ácidos Carboxílicos/química , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Membrana Celular/fisiologia , Proliferação de Células/efeitos dos fármacos , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Fulerenos/química , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão
12.
Theranostics ; 13(14): 4936-4951, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37771782

RESUMO

Neuroinflammation is considered to drive the pathogenic process of neuronal degeneration in Parkinson's disease (PD). However, effective anti-neuroinflammation therapeutics for PD still remain dissatisfactory. Here we explore a robust therapeutic strategy for PD using anti-neuroinflammatory fullerenes. Methods: Oral fullerene was prepared by a ball-milling method. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model was used to investigate the therapeutic effects and mechanisms of it. The gut microenvironment was evaluated by 16S rRNA gene sequencing, gas chromatography-mass spectrometry, quantitative polymerase chain reaction (Q-PCR), and western blot (WB). The neuroinflammation and neurodegeneration were evaluated by pathological analysis, Elisa kits, transmission electron microscopy, Q-PCR, WB and so on. Toxicity was assessed by weight, blood test and hematoxylin-eosin (HE) staining. Results: Oral fullerene therapeutic system that dissolved [60]fullerene into olive oil (abbreviated as OFO) was dexterously designed, which could reduce neuroinflammation via regulating the diversity of gut microbiome, increasing the contents of short chain fatty acids (SCFAs) and recovering the integrity of gut barrier. Accordingly, the reduction of neuroinflammation prevented dopaminergic neuronal degeneration. And thus, OFO significantly ameliorated motor deficits and fundamentally reversed dopamine (DA) loss in MPTP-induced PD mice. Of note, OFO exhibited low toxicity towards the living body. Conclusion: Our findings suggest that OFO is a safe-to-use, easy-to-apply, and prospective candidate for PD treatment in clinic, opening a therapeutic window for neuroinflammation-triggered neurodegeneration.

13.
Natl Sci Rev ; 10(12): nwad309, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38204453

RESUMO

Sleep deprivation (SD) is a severe public health threat that can cause systemic inflammation and nerve damage. Few effective and side-effect-free drugs are available to address SD. However, the bidirectional communications between the brain and gut provide new strategies for anti-SD therapeutics. Here we explored oral delivery of fullerene nano-antioxidants (FNAO) in the SD model to improve sleep by regulating abnormal intestinal barrier and systemic inflammation via the brain-gut axis. SD caused excessive reactive oxygen species (ROS) production and hyperactive inflammatory responses in the intestines of zebrafish and mouse models, leading to disturbed sleep patterns and reduced brain nerve activity. Of note, based on the property of the conjugated π bond of the C60 structure to absorb unpaired electrons, oral FNAO efficiently reduced the excessive ROS in the intestines, maintained redox homeostasis and intestinal barrier integrity, and ameliorated intestinal and systemic inflammation, resulting in superior sleep improvement. Our findings suggest that maintaining intestinal homeostasis may be a promising avenue for SD-related nerve injury therapy.

14.
Small ; 8(13): 2070-7, 2012 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-22508680

RESUMO

Carboxyfullerenes with different adduct numbers and cage sizes are tested as photosensitizers for photodynamic therapy (PDT). The photodynamic efficiency of these carboxyfullerenes depends mainly on the cage size, C(60) versus C(70) , and to a lesser extent on the adduct numbers. In particular, malonic acid modified C(70) fullerenes are more efficient than their C(60) counterparts as photosensitizers, and the mechanism of cell death induced by C(70) -carboxyfullerene under light irradiation is investigated in detail. The results indicate that cell death occurs via necrosis accompanied by membrane blebbing, which is a unique phenomenon for photosensitizer-induced cell death. Since C(70) -carboxyfullerene displays an efficient PDT property and negligible dark cytotoxicity, it is promising for use in PDT applications, especially in vascular capillary diseases usually occurring under the surface.


Assuntos
Fulerenos/química , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Fulerenos/uso terapêutico , Células HeLa , Humanos , Luz , Malonatos/química , Microscopia Eletrônica de Transmissão , Fármacos Fotossensibilizantes/uso terapêutico , Espécies Reativas de Oxigênio
15.
J Nanosci Nanotechnol ; 12(8): 6163-7, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22962722

RESUMO

Ginsenosides, the major chemical composition of Chinese white ginseng (Panax ginseng C. A. Meyer), can inhibit tumor, enhance body immune function, prevent neurodegeneration. In this paper, for the first time we reported that the amount of ginsenosides in the equivalent extraction of the nanoscale Chinese white ginseng particles (NWGP) was 2.5 times more than that of microscale Chinese white ginseng particles (WGP). And the extractions from NWGP (1000 microg/ml) reached a high tumor inhibition of 64% exposed to human lung carcinoma cells (A549) and 74% exposed to human cervical cancer cells (Hela) after 72 h. Our work shows that the nanoscale Chinese WGP greatly improves the bioavailability of ginsenosides.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Ginsenosídeos/isolamento & purificação , Panax/química , Extratos Vegetais/farmacologia , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , História do Século XIX , Humanos , Microscopia Eletrônica de Varredura , Nanotecnologia
16.
J Nanosci Nanotechnol ; 12(3): 1910-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22754998

RESUMO

Alpha-FeOOH and alpha-Fe2O3 with diverse morphologies (sea hedgehog-like, array-like, nanorod-like and nanoparticle-like) were synthesized through a simple and facile solvent-mediated method. The products with different morphologies can be prepared by adjusting the concentration of ferrous ions, reaction temperature and the pH value of the reaction solution in the rationally designed synthesis routes. All the products had a high BET surface area and exhibited an excellent catalytic ability in visible light induced degradation of rhodamine B.

17.
J Nanosci Nanotechnol ; 12(3): 2254-60, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22755045

RESUMO

By means of the density functional theory calculations, two C88(D2:35)-based endohedral fullerenes, Lu3C2@C88(D2:35) and Lu3N@C88(D2:35) which encapsulate tri-lutetium carbide and tri-lutetium nitride cluster were investigated. For the cores in Lu3C2@C88 and Lu3N@C88, the trivalent C2 and N respectively template a butterfly-shaped endohedral moiety and a planar tri-lutetium cluster within the same D2-symmetric C88 cage. Moreover, Lu3N@C88 - D2 has a closed-shell electronic structure but for LuC3C2@C88 - D2, it owns an unpaired electron mainly localized on the internal Lu3C2 cluster. These results clearly showed that the core unit C2(3) as well as N3- play an important role in constructing molecular structures and electronic features of metallofullerenes. Furthermore, the electrochemical redox potentials, and vibrational frequencies of the two endofullerenes agree well with our experimental results. The electronic structures, ionization energies, electron affinities, inner clusters' dynamic motions of them have been predicted to further disclose the characters of these two metallofullerenes.

18.
J Am Chem Soc ; 133(25): 9741-50, 2011 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-21548647

RESUMO

The dimetallic endohedral heterofullerene (EHF), Gd(2)@C(79)N, was prepared and isolated in a relatively high yield when compared with the earlier reported heterofullerene, Y(2)@C(79)N. Computational (DFT), chemical reactivity, Raman, and electrochemical studies all suggest that the purified Gd(2)@C(79)N, with the heterofullerene cage, (C(79)N)(5-) has comparable stability with other better known isoelectronic metallofullerene (C(80))(6-) cage species (e.g., Gd(3)N@C(80)). These results describe an exceptionally stable paramagnetic molecule with low chemical reactivity with the unpaired electron spin density localized on the internal diatomic gadolinium cluster and not on the heterofullerene cage. EPR studies confirm that the spin state of Gd(2)@C(79)N is characterized by a half-integer spin quantum number of S = 15/2. The spin (S = ½) on the N atom of the fullerene cage and two octet spins (S = 7/2) of two encapsulated gadoliniums are coupled with each other in a ferromagnetic manner with a small zero-field splitting parameter D. Because the central line of Gd(2)@C(79)N is due to the Kramer's doublet with a half-integer spin quantum number of S = 15/2, this relatively sharp line is prominent and the anisotropic nature of the line is weak. Interestingly, in contrast with most Gd(3+) ion environments, the central EPR line (g = 1.978) is observable even at room temperature in a toluene solution. Finally, we report the first EHF derivative, a diethyl bromomalonate monoadduct of Gd(2)@C(79)N, which was prepared and isolated via a modified Bingel-Hirsch reaction.


Assuntos
Fulerenos/química , Gadolínio , Magnetismo , Espectroscopia de Ressonância de Spin Eletrônica
19.
Phys Chem Chem Phys ; 13(2): 428-33, 2011 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-21088791

RESUMO

A series of novel supramolecular complexes composed of a three-point binding C(60)-trispyridylporphyrin dyad (1) or C(70)-trispyridylporphyrin dyad (2) and zinc tetraphenylporphyrin (ZnP) were constructed by adopting a "covalent-coordinate" bonding approach, composed of three-point binding. The dyads and self-assembled supramolecular triads or pentads formed by coordinating the pyridine groups located on the dyads to ZnP, have been characterized by means of spectral and electrochemical techniques. The formation constants of ZnP-1 and ZnP-2 complexes were calculated as 1.4 × 10(4) M(-1) and 2.0 × 10(4) M(-1), respectively, and the Stern-Volmer quenching constants K(SV) were founded to be 2.9 × 10(4) M(-1) and 5.5 × 10(4) M(-1), respectively, which are much higher than those of other supramolecular complexes such as previously reported ZnP-3 (N-ethyl-2-(4-pyridyl)-3,4-fulleropyrrolidine). The electrochemical investigations of these complexes suggest weak interactions between the constituents in the ground state. The excited states of the complexes were further monitored by time-resolved fluorescence measurements. The results revealed that the presence of the multiple binding point dyads (1 or 2) slightly accelerated the fluorescence decay of ZnP in o-DCB relative to that of the "single-point" bound supramolecular complex ZnP-3. In comparison with 1 and 2, C(70) is suggested as a better electron acceptor relative to C(60). DFT calculations on a model of supramolecular complex ZnP-1 (with one ZnP entity) were performed. The results revealed that the lowest unoccupied molecular orbital (LUMO) is mainly located on the fullerene cage, while the highest occupied molecular orbital (HOMO) is mainly located on the ZnP macrocycle ring, predicting the formation of radical ion pair ZnP(+)˙-H(2)P-C(60)(-)˙ during photo-induced reaction.

20.
Nano Lett ; 10(8): 2843-8, 2010 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-20698597

RESUMO

Single-walled carbon nanohorns (SWNHs) are new carbonaceous materials. In this paper, we report the first successful preparation of SWNHs encapsulating trimetallic nitride template endohedral metallofullerenes (TNT-EMFs). The resultant materials were functionalized by a high-speed vibration milling method and conjugated with CdSe/ZnS quantum dots (QDs). The successful encapsulation of TNT-EMFs and external functionalization with QDs provide a dual diagnostic platform for in vitro and in vivo biomedical applications of these new carbonaceous materials.


Assuntos
Fulerenos/química , Metais/química , Nanotubos de Carbono , Pontos Quânticos , Técnicas In Vitro
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