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1.
Chem Biodivers ; : e202401388, 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39073302

RESUMO

Four new alkaloids Chaeronepaline-A (1), Chaeronepaline-B (2), Chaeronepaline-C (3), and Chaeronepaline-D (4) were isolated from Corydalis chaerophylla D.C. collected from Nepal and their structures were elucidated by spectroscopic data, 1D, 2D NMR and mass spectrometry. The structures were established as 3,12- Dimethoxy-5,6-dihydroisoquinolino [2,1-b] isoquinolin- 7- ium- 2, 9- diol (1), 7-methyl-5, 6, 7, 8-tetrahydroisoquinoline- 2, 3- methylenedioxy- (8-> 9)- 10, 12- methylenedioxy- benzoic-16-acid (2), 7- methyl-5, 6, 7, 8- tetrahydro- 8H-spiro-9,14-dihydroxy-11,12-methylenedioxy-indane-isoquinoline (3) and 7- methyl-5, 6, 7, 8- tetrahydro- 8H-spiro-9,14-dihydroxy-11,12-methylenedioxy-indane-isoquinoline-N-oxide (4). The new alkaloids were tested in human hepatoma cell line to assess their ability to modulate the expression of low-density lipoprotein receptor (LDL-R), of proprotein convertase subtilisin/kexin 9 (PCSK9) and to affect cellular cholesterol biosynthesis with the aim to evaluate their potential hypocholesterolemic effect. Results indicated that compounds 2 and 3 upregulate the LDLR, and inhibited the cholesterol biosynthesis with compound 2, which also reduced the secretion of PCSK9 by Huh7 cells. These in vitro data indicated a potential hypocholesterolemic effect of compound 2 that requires further in vivo validation.

2.
Sci Technol Adv Mater ; 25(1): 2315014, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38419801

RESUMO

The interaction between diverse nanoarchitectured fullerenes and cells is crucial for biomedical applications. Here, we detailed the preparation of hydrophilic self-assembled fullerenes by the liquid-liquid interfacial precipitation (LLIP) method and hydrophilic coating of the materials as a possible vascularization strategy. The interactions of vascular endothelial cells (ECs) with hydrophilic fullerene nanotubes (FNT-P) and hydrophilic fullerene nanowhiskers (FNW-P) were investigated. The average length and diameter of FNT-P were 16 ± 2 µm and 3.4 ± 0.4 µm (i.e. aspect ratios of 4.6), respectively. The average length and diameter of FNW-P were 65 ± 8 µm and 1.2 ± 0.2 µm (i.e. aspect ratios of 53.9), respectively. For two-dimensional (2D) culture after 7 days, the ECs remained viable and proliferated up to ~ 420% and ~ 400% with FNT-P and FNW-P of 50 µg/mL, respectively. Furthermore, an optimized chitosan-based self-healing hydrogel with a modulus of ~400 Pa was developed and used to incorporate self-assembled fullerenes as in vitro three-dimensional (3D) platforms to investigate the impact of FNT-P and FNW-P on ECs within a 3D environment. The addition of FNW-P or FNT-P (50 µg/mL) in the hydrogel system led to proliferation rates of ECs up to ~323% and ~280%, respectively, after 7 days of culture. The ECs in FNW-P hydrogel displayed an elongated shape with aligned morphology, while those in FNT-P hydrogel exhibited a rounded and clustered distribution. Vascular-related gene expressions of ECs were significantly upregulated through interactions with these fullerenes. Thus, the combined use of different nanoarchitectured self-assembled fullerenes and self-healing hydrogels may offer environmental cues influencing EC development in a 3D biomimetic microenvironment, holding promise for advancing vascularization strategy in tissue engineering.


Self-assembled fullerenes with large aspect ratios modulate the morphology and gene expression of endothelial cells within a soft biomimetic 3D microenvironment, representing a promising new vascularization strategy in tissue engineering.

3.
Sci Technol Adv Mater ; 25(1): 2322458, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38440402

RESUMO

A series of porous organic polymers based on a singlet oxygen generating oxoporphyinogen ('OxP') has been successfully prepared from a pseudotetrahedral OxP-tetraamine precursor (OxP(4-NH2Bn)4) by its reaction with tetracarboxylic acid dianhydrides under suitable conditions. Of the compounds studied, those containing naphthalene (OxP-N) and perylene (OxP-P) spacers, respectively, have large surface areas (~530 m2 g-1). On the other hand, the derivative with a simple benzene spacer (OxP-B) exhibits the best 1O2 generating capability. Although the starting OxP-tetraamine precursor is a poor 1O2 generator, its incorporation into OxP POPs leads to a significant enhancement of 1O2 productivity, which is largely due to the transformation of NH2 groups to electron-withdrawing diimides. Overall 1O2 production efficacy of OxP-POPs under irradiation by visible light is significantly improved over the common reference material PCN-222. All the materials OxP-B, OxP-N and OxP-P promote oxidation of thioanisole involving conversion of ambient triplet state oxygen to singlet oxygen under visible light irradiation and its reaction with the sulfide. Although the reaction rate of the oxidation promoted by OxP POPs is generally lower than for conventional materials (such as PCN-222) or previously studied OxP derivatives, undesired overoxidation of the substrate to methyl phenyl sulfone is suppressed. For organic sulfides, selectivity of oxidation is especially important for detoxification of mustard gas (bis(2-chloroethyl)sulfide) or similarly toxic compounds since controlled oxidation leads to the low toxicity bis(2-chloroethyl)sulfoxide while overoxidation leads to intoxification (since bis(2-chloroethyl)sulfone presents greater toxicity to humans than the sulfide substrate). Therefore, OxP POPs capable of promoting selective oxidation of sulfides to sulfoxides have excellent potential to be used as mild and selective detoxification agents.


Oxoporphyrinogen (OxP) is a unique chromophore compound in that it is intrinsically de-aggregated allowing large quantum yields of singlet oxygen generation. Due to its structure, OxP is also an ideal building block for porous systems. In this work, we describe the first incorporation of OxP in highly stable microporous polymers strongly enhanced singlet oxygen generation for selective oxidation of organic sulfides to sulfoxides (as a model reaction) under heterogeneous conditions. The novelty of this work lies in the high stability and easy recovery of the materials, the synergetic enhancement of singlet oxygen generation in the polymers over the starting OxP, and the excellent selectivity for the oxidation reaction.

4.
J Am Chem Soc ; 144(24): 10830-10843, 2022 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-35587544

RESUMO

Chromophores that generate singlet oxygen (1O2) in water are essential to developing noninvasive disease treatments using photodynamic therapy (PDT). A facile approach for formation of stable colloidal nanoparticles of 1O2 photosensitizers, which exhibit aggregation enhanced 1O2 generation in water toward applications as PDT agents, is reported. Chromophore encryption within a fuchsonarene macrocyclic scaffold insulates the photosensitizer from aggregation induced deactivation pathways, enabling a higher chromophore density than typical 1O2 generating nanoparticles. Aggregation enhanced 1O2 generation in water is observed, and variation in molecular structure allows for regulation of the physical properties of the nanoparticles which ultimately affects the 1O2 generation. In vitro activity and the ability of the particles to pass through the cell membrane into the cytoplasm is demonstrated using confocal fluorescence microscopy with HeLa cells. Photosensitizer encryption in rigid macrocycles, such as fuchsonarenes, offers new prospects for the production of biocompatible nanoarchitectures for applications involving 1O2 generation.


Assuntos
Fotoquimioterapia , Fármacos Fotossensibilizantes , Células HeLa , Humanos , Oxigênio , Fármacos Fotossensibilizantes/química , Oxigênio Singlete/metabolismo , Água
5.
Int J Mol Sci ; 23(10)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35628264

RESUMO

The simplicity of fullerenes as assembled components provides attractive opportunities for basic understanding in self-assembly research. We applied in situ reactive methods to the self-assembly process of C60 molecules with melamine/ethylenediamine components in solution, resulting in a novel type of fullerene assemblies, micron-sized two-dimensional, amorphous shape-regular objects, fullerene rosettes. ATR−FTIR spectra, XPS, and TGA results suggest that the melamine/ethylenediamine components strongly interact and/or are covalently linked with fullerenes in the fullerene rosettes. The broad peak for layer spacing in the XRD patterns of the fullerene rosettes corresponds roughly to the interdigitated fullerene bilayer or monolayer of modified fullerene molecules. The fullerene rosettes are made from the accumulation of bilayer/monolayer assemblies of hybridized fullerenes in low crystallinity. Prototype sensor systems were fabricated upon immobilization of the fullerene rosettes onto surfaces of a quartz crystal microbalance (QCM), and selective sensing of formic acid was demonstrated as preliminary results for social-demanded toxic material sensing. The QCM sensor with fullerene rosette is categorized as one of the large-response sensors among reported examples. In selectivity to formic acids against basic guests (formic acid/pyridine >30) or aromatic guests (formic acid/toluene >110), the fullerene rosette-based QCM sensor also showed superior performance.


Assuntos
Fulerenos , Etilenodiaminas , Gases , Técnicas de Microbalança de Cristal de Quartzo
6.
Biomacromolecules ; 22(3): 1053-1064, 2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33411512

RESUMO

Three-dimensional (3D) bioprinting is a technology that can precisely fabricate customized tissues and organs. Hydrogel materials that can embed living cells for use in 3D printing are called bioinks. However, there are only limited options of bioinks currently because they require the following features at once, such as printability, repetitive layer-by-layer stacking (stackability), structure stabilization, and biological properties. A polyurethane-gelatin double network hydrogel bioink was previously reported to own tunable modulus through changing the solid content, but cell viability at the high solid content is inevitably reduced. In the present study, the reinforcement effects of a metal-organic framework (MOF), zeolitic imidazolate framework-8 (ZIF-8), in the PUG bioink were evaluated. The printability, stackability, thermoresponsiveness, and shear-thinning behavior of the PUG-ZIF-8 composite hydrogels were examined. It was found that the PUG composite hydrogel containing 1250 µg/mL ZIF-8 crystals showed significant structural stability and modulus enhancement (∼2.5-fold). However, the PUG bioink containing 1250 µg/mL ZIF-8 crystals may lead to cell senescence or death. The cytocompatible concentration of ZIF-8 crystals in the bioink was about 875 µg/mL, and this concentration was much higher than the reported tolerable amount (∼50 µg/mL) of ZIF-8 for biomedical applications. The strong reinforcement effect of ZIF-8 and the drug-loading/sensing possibilities of MOFs may open new opportunities for using MOFs in 3D bioprinting applications.


Assuntos
Bioimpressão , Estruturas Metalorgânicas , Gelatina , Hidrogéis , Impressão Tridimensional , Reologia , Engenharia Tecidual , Alicerces Teciduais
7.
Sci Technol Adv Mater ; 22(1): 100-112, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33762890

RESUMO

Many researchers working on the development of Dye-sensitized solar cells (DSCs) continue to focus on the synthesis of photoanode materials with high surface area, along with high light scattering ability to enhance light harvesting efficiency (LHE). On the other hand, dye packing density, which can also affect the LHE significantly, is often overlooked. Solvothermally synthesized anatase TiO2 nanoparticles (SANP) were obtained by a new and simple approach using a mixed solvent, ethanol and acetic acid. SANP were applied as a photoanodes material in DSCs using a metal-free organic dye (D149) or organometallic dye (N719) dyes. The dye loading (packing density) was examined in term of the isoelectric point (IEP) and the contribution of this, in addition to light scattering effects were shown to control the devices photovoltaic efficiency of the devices; specifically when compared with ones employing commercially available TiO2 nanoparticles (either transparent or a bilayer structure with a transparent layer and a scattering one). SANP photoanodes sensitized with D149 dye were found to be optimised at 10 µm, yielding photovoltaic conversion efficiencies of 6.9%, superior to for transparent or transparent + scattering films from the commercial source (5.6% and 5.9%, respectively). Further to this, an efficiency of 7.7% PCE was achieved using a SANP photoanode sensitized with N719 dye, with 7.2% seen for the transparent photoanode and 7.9% with a scattering layer. The high efficiencies of devices based on of SANP photoanode are attributed to the high dye loading capability in addition to good light scattering. A further point of interest is that even with the increased reactivity of the surface towards dye adsorption, we did not observe any significant increase in recombination with the redox mediator, presumably due to this increased dye loading providing better shielding.

8.
Molecules ; 26(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34361787

RESUMO

Nanoarchitectonics of two-dimensional materials from zero-dimensional fullerenes is mainly introduced in this short review. Fullerenes are simple objects with mono-elemental (carbon) composition and zero-dimensional structure. However, fullerenes and their derivatives can create various types of two-dimensional materials. The exemplified approaches demonstrated fabrications of various two-dimensional materials including size-tunable hexagonal fullerene nanosheet, two-dimensional fullerene nano-mesh, van der Waals two-dimensional fullerene solid, fullerene/ferrocene hybrid hexagonal nanosheet, fullerene/cobalt porphyrin hybrid nanosheet, two-dimensional fullerene array in the supramolecular template, two-dimensional van der Waals supramolecular framework, supramolecular fullerene liquid crystal, frustrated layered self-assembly from two-dimensional nanosheet, and hierarchical zero-to-one-to-two dimensional fullerene assembly for cell culture.

9.
Phys Chem Chem Phys ; 22(40): 23276-23285, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-33030486

RESUMO

Ionic self-assembly is a simple yet powerful method to obtain robust nanostructures. Herewith, we use mixtures of oppositely-charged porphyrins that can act as mesogens to form chromonic liquid crystals in water, i.e., molecular stacks with orientational (nematic) or positional (hexagonal) order. Electrostatic locking coupled with π-π interactions between aromatic groups within the stacks, together with inter-stack hydrogen bonding induce formation of all-organic crystalline nanofibers with high aspect ratio (a few tenths of nanometers in width but several tenths of micrometers in length) and that display branching. The nanofibers prepared from metal-free porphyrin units feature interesting optical properties, including an absorption spectrum that is different from the simple sum of the individual spectra of the components, which is attributed to a striking aggregation-induced chromism. When in contact with some polar organic solvents the materials become fluorescent, as a result of disaggregation. In a proof-of-concept, the obtained self-assembled one-dimensional (1D) materials were carbonized (yield ca. 60%) to produce nitrogen-doped carbon nanofibers that can be used as active electrode materials for energy storage applications.

10.
Chem Rec ; 19(9): 1891-1912, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30230688

RESUMO

The challenges of pollution, environmental science, and energy consumption have become global issues of broad societal importance. In order to address these challenges, novel functional systems and advanced materials are needed to achieve high efficiency, low emission, and environmentally friendly performance. A promising approach involves nanostructure-level controls of functional material design through a novel concept, nanoarchitectonics. In this account article, we summarize nanoarchitectonic approaches to create nanoscale platform structures that are potentially useful for environmentally green and bioprocessing applications. The introduced platforms are roughly classified into (i) membrane platforms and (ii) nanostructured platforms. The examples are discussed together with the relevant chemical processes, environmental sensing, bio-related interaction analyses, materials for environmental remediation, non-precious metal catalysts, and facile separation for biomedical uses.


Assuntos
Materiais Biomiméticos/química , Bicamadas Lipídicas/química , Nanopartículas/química , Nanotecnologia/métodos , Catálise , Recuperação e Remediação Ambiental/métodos , Química Verde/métodos
11.
Sci Technol Adv Mater ; 20(1): 51-95, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30787960

RESUMO

The development of science and technology of advanced materials using nanoscale units can be conducted by a novel concept involving combination of nanotechnology methodology with various research disciplines, especially supramolecular chemistry. The novel concept is called 'nanoarchitectonics' where self-assembly processes are crucial in many cases involving a wide range of component materials. This review of self-assembly processes re-examines recent progress in materials nanoarchitectonics. It is composed of three main sections: (1) the first short section describes typical examples of self-assembly research to outline the matters discussed in this review; (2) the second section summarizes self-assemblies at interfaces from general viewpoints; and (3) the final section is focused on self-assembly processes at interfaces. The examples presented demonstrate the strikingly wide range of possibilities and future potential of self-assembly processes and their important contribution to materials nanoarchitectonics. The research examples described in this review cover variously structured objects including molecular machines, molecular receptors, molecular pliers, molecular rotors, nanoparticles, nanosheets, nanotubes, nanowires, nanoflakes, nanocubes, nanodisks, nanoring, block copolymers, hyperbranched polymers, supramolecular polymers, supramolecular gels, liquid crystals, Langmuir monolayers, Langmuir-Blodgett films, self-assembled monolayers, thin films, layer-by-layer structures, breath figure motif structures, two-dimensional molecular patterns, fullerene crystals, metal-organic frameworks, coordination polymers, coordination capsules, porous carbon spheres, mesoporous materials, polynuclear catalysts, DNA origamis, transmembrane channels, peptide conjugates, and vesicles, as well as functional materials for sensing, surface-enhanced Raman spectroscopy, photovoltaics, charge transport, excitation energy transfer, light-harvesting, photocatalysts, field effect transistors, logic gates, organic semiconductors, thin-film-based devices, drug delivery, cell culture, supramolecular differentiation, molecular recognition, molecular tuning, and hand-operating (hand-operated) nanotechnology.

12.
Sensors (Basel) ; 19(2)2019 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-30641916

RESUMO

Here we report the aromatic vapor sensing performance of bitter melon shaped nanoporous fullerene C60 crystals that are self-assembled at a liquid-liquid interface between isopropyl alcohol and C60 solution in dodecylbenzene at 25 °C. Average length and center diameter of the crystals were ca. 10 µm and ~2 µm, respectively. Powder X-ray diffraction pattern (pXRD) confirmed a face-centered cubic (fcc) structure with cell dimension ca. a = 1.4272 nm, and V = 2.907 nm³, which is similar to that of the pristine fullerene C60. Transmission electron microscopy (TEM) confirmed the presence of a nanoporous structure. Quartz crystal microbalance (QCM) results showed that the bitter melon shaped nanoporous C60 performs as an excellent sensing system, particularly for aromatic vapors, due to their easy diffusion through the porous architecture and strong π⁻π interactions with the sp²-carbon.

13.
Langmuir ; 34(29): 8670-8677, 2018 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-29940738

RESUMO

We demonstrate a novel charge-free reverse wormlike micelle (RWLM) consisting of a ternary mixture of a nonionic amphiphilic block copolymer, fatty acid alkyl ester oil, and water under ambient conditions. Nonionic amphiphile tetra-[poly(oxyethylene)-poly(oxybutylene)]pentaerythrityl ether (TEBPE) self-assembled into spheroid-type micelles in nonaqueous media isopropyl myristate (IPM) with viscosity comparable to that of IPM. The addition of water increases viscosity only slightly up to a certain concentration of water and then drastically, demonstrating the sphere-to-wormlike micelle transition as confirmed by small-angle X-ray scattering. Further increase in water decreases the viscosity after attaining a maximum value. The zero shear viscosity (η0) of the 10 wt % TEBPE/IPM system reached the maximum at 2.6 wt % water and ca. 56 Pa·s, which is ∼fivefold higher than that of water. Dynamic rheological measurements on the highly viscous solutions confirmed the viscoelastic behavior and could be described by the Maxwell model. Conductivity, measured in the presence of a conductive probe, 1-ethyl-3-methylimidazolium tetrafluoroborate, was found to be higher for viscous samples compared to the nonviscous samples, suggesting the static percolation caused by the RWLM formation. Decrease in η0 and conductivity beyond a maximum suggests the shortening of reverse micelles. A similar behavior has been observed in other fatty acid alkyl ester oils of different alkyl chain lengths. Note that most of the RWLM systems previously reported are based on phosphatidylcholine (PC). Formulation and structure-properties related to non-PC-based RWLMs have been rarely explored. Non-PC-based RWLMs using chemically stable and low-cost synthetic molecules can be applied not only in pharmaceuticals and cosmetics but also in a wide range of applications including drag reduction agents for nonaqueous fluids and as a template for nanomaterial synthesis.

14.
Chem Rec ; 18(7-8): 676-695, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29205796

RESUMO

Important points for the fabrication of functional materials are the creation of nanoscale/molecular-scale units and architecting them into functional materials and systems. Recently, a new conceptual paradigm, nanoarchitectonics, has been proposed to combine nanotechnology and other methodologies including supramolecular chemistry, self-assembly and self-organization to satisfy major features of nanoscience and promote the creation of functional materials and systems. In this account article, our recent research results in materials development based on the nanoarchitectonics concept are summarized in two stories, (i) nanoarchitectonics from fullerenes as the simplest nano-units and (ii) dimension-dependent nanoarchitectonics from various structural units. The former demonstrates creativity of the nanoarchitectonics concept only with simple construction stuffs on materials fabrications, and a wide range of material applicability for the nanoarchitectonics strategy is realized in the latter ones.

15.
Phys Chem Chem Phys ; 20(27): 18873-18878, 2018 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-29968876

RESUMO

A hierarchical heterostructure composed of silver nanoparticles (Ag-NPs: average diameter ∼10 nm) on fullerene nanorods (FNRs: average length ∼11 µm and average diameter ∼200 nm) was fabricated using a simple solution route. It was used as an effective single particle freestanding surface enhanced Raman scattering (SERS) substrate for the detection of target molecules (Rhodamine 6G: R6G). FNRs were formed ultra-rapidly (formation process completed in a few seconds) at a liquid-liquid interface of methanol and C60/mesitylene solution then Ag-NPs were grown directly on the surfaces of the FNRs by treatment with a solution of silver nitrate in ethanol. This unique hierarchical heterostructure allows efficient adsorption of target molecules also acting as an effective SERS substrate capable of detecting the adsorbed R6G molecules in the nanomolar concentration range. In this study, SERS spectra are acquired on an isolated single Ag-FNR for the detection of the absorbed molecule rather than from a bulk, large area film composed of silver/gold nanoparticles as used in conventional methods. Thus, this work provides a new approach for the design and fabrication of freestanding SERS substrates for molecular detection applications.

16.
Angew Chem Int Ed Engl ; 57(31): 9679-9683, 2018 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-29917300

RESUMO

Two-dimensional (2D) carbon nanomaterials possessing promising physical and chemical properties find applications in high-performance energy storage devices and catalysts. However, large-scale fabrication of 2D carbon nanostructures is based on a few specific carbon templates or precursors and poses a formidable challenge. Now a new bottom-up method for carbon nanosheet fabrication using a newly designed anisotropic carbon nanoring molecule, CPPhen, is presented. CPPhen was self-assembled at a dynamic air-water interface with a vortex motion to afford molecular nanosheets, which were then carbonized under inert gas flow. Their nanosheet morphologies were retained after carbonization, which has never been seen for low-molecular weight compounds. Furthermore, adding pyridine as a nitrogen dopant in the self-assembly step successfully afforded nitrogen-doped carbon nanosheets containing mainly pyridinic nitrogen species.

17.
Phys Chem Chem Phys ; 19(43): 29099-29105, 2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29075701

RESUMO

Polycyclic aromatic compounds (naphthalene, anthracene and pyrene) have been intercalated into the superstructures of fullerene nanowhiskers, using a facile liquid-liquid interfacial precipitation (LLIP) method. Due to the interaction between polycyclic molecules and fullerene, the growth of fullerene crystals was interfered in comparison to the fullerene crystal growth without the polycyclic molecules, resulting in the formation of fullerene superstructures with various nanofeatures. Moreover, the fluorescence emissions of the fullerene superstructures were significantly changed due to the intercalation of the polycyclic molecules, implying the influence of molecular packing on the electron transfer within the nanostructures. These results may bring new insights on the control of fullerene nanostructures and to manipulate their optical properties in optoelectronic devices.

18.
Sci Technol Adv Mater ; 18(1): 147-151, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28458738

RESUMO

We developed ceramic core-shell materials based on abundant halloysite clay nanotubes with enhanced heavy metal ions loading through Schiff base binding. These clay tubes are formed by rolling alumosilicate sheets and have diameter of c.50 nm, a lumen of 15 nm and length ~1 µm. This allowed for synthesis of metal nanoparticles at the selected position: (1) on the outer surface seeding 3-5 nm metal particles on the tubes; (2) inside the tube's central lumen resulting in 10-12 nm diameter metal cores shelled with ceramic wall; and (3) smaller metal nanoparticles intercalated in the tube's wall allowing up to 9 wt% of Ru, and Ag loading. These composite materials have high surface area providing a good support for catalytic nanoparticles, and can also be used for sorption of metal ions from aqueous solutions.

19.
Langmuir ; 32(47): 12511-12519, 2016 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-27267221

RESUMO

Here, we report the structural and morphological modulation of fullerene C60 crystals induced by nonionic surfactants diglycerol monolaurate (C12G2) and monomyristate (C14G2). C60 crystals synthesized at a liquid-liquid interface comprising isopropyl alcohol (IPA) and a saturated solution of C60 in ethylbenzene (EB) exhibited a one-dimensional (1D) morphology with well-defined faceted structure. Average length and diameter of the faceted rods were ca. 4.8 µm and 747 nm, respectively. Powder X-ray diffraction pattern (pXRD) confirmed a hexagonal-close packed (hcp) structure with cell dimensions ca. a = 2.394 nm and c = 1.388 nm. The 1D rod morphology of C60 crystals was transformed into "Konpeito candy-like" crystals (average diameter ca. 1.2 µm) when the C60 crystals were grown in the presence of C12G2 or C14G2 surfactant (1%) in EB. The pXRD spectra of "Konpeito-like" crystals could be assigned to the face-centered cubic (fcc) phase with cell dimensions ca. a = 1.4309 nm (for C12G2) and a = 1.4318 nm (for C14G2). However, clusters or aggregates of C60 lacking a uniform morphology were observed at lower surfactant concentrations (0.1%), although these crystals exhibited an fcc crystal structure. The self-assembled 1D faceted C60 crystals and "Konpeito-like" C60 crystals exhibited intense photoluminescence (PL) (∼35 times greater than pC60) and a blue-shifted PL intensity maximum (∼15 nm) compared to those of pC60, demonstrating the potential use of this method for the control of the optoelectronic properties of fullerene nanostructures. The "Konpeito-like" crystals were transformed into high surface area nanoporous carbon with a graphitic microstructure upon heat-treatment at 2000 °C. The heat-treated samples showed enhanced electrochemical supercapacitance performance (specific capacitance is ca. 175 F g-1, which is about 20 times greater than pC60) with long cyclic stability demonstrating the potential of the materials in supercapacitor device fabrication.

20.
Analyst ; 141(9): 2629-38, 2016 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-26876528

RESUMO

Recently, the nanoarchitectonics concept has been proposed to fabricate functional materials on the basis of concerted harmonization actions to control materials organization. In this review, we introduce recent several sensor designs from viewpoints of nanoarchitectonics that are classified into three categories: (i) inside nanoarchitectonics, (ii) outside nanoarchitectonics, and (iii) hierarchic nanoarchitectonics. In addition, various nanocarbons, such as carbon nanotubes, graphene derivatives, fullerene assemblies and nanoporous carbons, are selected as standard materials. In the first section, design and fabrication of mesoporous or nanoporous materials for enhanced sensing are especially exemplified as inside nanoarchitectonics. In the next section, recent examples of layer-by-layer nanoarchitectures for sensor fabrications are explained for outside nanoarchitectonics. Finally, their combined strategies for hierarchic carbon nanoarchitectonics are introduced as advanced sensor materials designs.

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