Potential Functional Material Research Articles

Sonochemically prepared nanosized BiFeO3 as novel SO2 sensor

Bismuth ferrite (BiFeO3) without any co-formed impurity phase was synthesized by sonochemical method. The average crystallite sizes of synthesized BiFeO3 for two sonication times of 40min and 2h were found to be 38 and 32nm and the corresponding band gaps were 2.1 and 2.2eV, respectively. In contrast to BiFeO3 synthesized by conventional precipitation route which gives rise to co-formed impurity phases, the sonochemically prepared phase-pure BiFeO3 nanoparticles exhibited an excellent low-ppm SO2 sensing behaviour with fast response and recovery. Also the sonochemically synthesized BiFeO3 was selective to SO2 in presence of carbon monoxide and butane and may turn out to be a potential functional material for SO2 leak alarms.

Research progress on the hybrid luminescent materials based on layered rare-earth hydroxides

Layered rare-earth hydroxides (LRHs), which have the general composition RE₂(OH)₅X·<italic>n</italic>H₂O (where RE=rare-earth elements and X=anion), are a new group of important two-dimensionally inorganic layered matrices. The combination of various rare-earth and exchangeable ions is a unique feature of this layered rare-earth hydroxides family, which makes LRHs to be a kind of potential new functional materials. Herein, the research progresses of hybrid luminescent materials based on the layered rare-earth hydroxides have been reviewed. The effects of the host-guest interactions on the photophysical behaviors and stabilities of the hybrid materials have also been discussed.

Paradigms shift when solvent-less fluids come into play.

Solvent-less organic fluids are a new class of functional soft materials. Here the available fluid matrix makes it equally competitive with the solvent assisted systems. In this Perspective, the ways in which organic fluids challenge the established and accepted paradigms is highlighted. In general, fundamental properties such as photoisomerization, energy/electron transfer, photon upconversion and reversible dioxygen binding are controlled by solvents and/or solvent polarity, the presence of oxygen etc. Here solvent-less fluids challenge the paradigms by realizing it under neat, solvent-less and ambient conditions. This new phase of research has created many potential functional materials, which work better and more efficiently compared to the solvent assisted systems. Hence this relatively new research topic and the results need special attention. Here we discuss a few representative examples to point out the challenges offered in their functioning.

Novel anion conductors – conductivity, thermodynamic stability and hydration of anion-substituted mayenite-type cage compounds C12A7:X (X = O, OH, Cl, F, CN, S, N)

Mayenite (Ca12Al14O33) is a highly interesting functional material not only in view of its unique crystal structure as a cage compound but also for its variety of possible applications. Its ability to incorporate foreign ions into the cage structure opens the possibility to create new types of solid electrolytes and even electrides. Therefore, the conductivity of various anion substituted mayenites was measured as a function of temperature. Due to controversial reports on the stability of mayenite under specific thermodynamic conditions (dry, wet, reducing, and high temperature), a comprehensive study on the stability was performed. Mayenite is clearly not stable under dry conditions (ppm H2O < 100) at temperatures above 1050 °C, and thus, the mayenite phase vanishes from the calcium aluminate phase diagram below a minimum humidity. Two decomposition reactions were observed and are described in detail. To get further insight into the mechanism of hydration of mayenite, the conductivity was measured as a function of water vapour pressure in a range of -5 ≤ lg[pH2O/bar] ≤ -1.6 at temperatures ranging from 1000 °C ≤ θ ≤ 1200 °C. The hydration isotherms are described with high accuracy by the underlying point defect model, which is confirmed in a wide range of water vapour pressure.

A 1D anionic lanthanide coordination polymer as an adsorbent material for the selective uptake of cationic dyes from aqueous solutions.

A 1D anionic lanthanide coordination polymer {[(CH(3))(2)NH(2)] [(H(2)abtc)(2)Ho(H(2)O)]}n () (H(4)abtc = 3,3',5,5'-azobenzene-tetracarboxylic acid) has been synthesized under hydrothermal reaction conditions. The protonated [(CH(3))(2)NH(2)](+) is generated from decomposed DMA during the reaction, and balances the negative charge of the framework. The as-obtained samples were characterized using single-crystal and powder X-ray diffraction and TGA. Interestingly, 1 can selectively capture cationic dye molecules from mixtures of dye molecules containing different charges in aqueous solutions. Furthermore, 1 exhibits a different adsorption efficiency toward different cationic dyes (crystal violet, rhodamine B, safranine T and methylene blue). Among the studied dyes, methylene blue has a higher adsorption efficiency in comparison to the others. Thus, complex 1 could serve as a good candidate material for the selective removal of cationic dyes during the treatment of wastewater.

Oligopeptide-assisted self-assembly of oligothiophenes: co-assembly and chirality transfer.

The biomolecule-assisted self-assembly of semiconductive molecules has been developed recently for the formation of potential bio-based functional materials. Oligopeptide-assisted self-assembly of oligothiophene through weak intermolecular interactions was investigated; specifically the self-assembly and chirality-transfer behavior of achiral oligothiophenes in the presence of an oligopeptide with a strong tendency to form β-sheets. Two kinds of oligothiophenes without (QT) or with (QTDA) carboxylic groups were selected to explore the effect of the end functional group on self-assembly and chirality transfer. In both cases, organogels were formed. However, the assembly behavior of QT was quite different from that of QTDA. It was found that QT formed an organogel with the oligopeptide and co-assembled into chiral nanostructures. Conversely, although QTDA also formed a gel with the oligopeptide, it has a strong tendency to self-assemble independently. However, during the formation of the xerogel, the chirality of the oligopeptide can also be transferred to the QTDA assemblies. Different assembly models were proposed to explain the assembly behavior.

Crystal structural transformation accompanied by magnetic transition in MnCo1−xFexGe alloys

The effects of Fe-doping on the crystal structure and martensitic transformation (MT) temperature in MnCoGe alloy have been investigated by using x-ray diffraction, calorimetry and magnetic measurements. Substitution of Fe for Co atoms can stabilize the parent phase and significantly lower the MT temperature of the MnCoGe alloy. By tuning the Fe content, the magnetostructural transition from paramagnetic parent phase (i.e. austenite) with a Ni2In-type hexagonal structure to ferromagnetic TiNiSi-type martensite can be realized in a temperature window determined by the Curie temperature of the austenite and that of the martensite. A large difference in magnetization between the austenite and martensite, accompanied by the magnetostructural coupling, gives rise to the magnetic-field-induced temperature shift of MT, which makes the MnCo1−xFexGe alloys being a new kind of potential magnetic functional materials used as the magnetic-field-driven actuator or magnetic refrigeration material.

Synthesis of string-bean-like anisotropic titania nanoparticles with basic amino acids

An “assembly–aggregation–peptization” approach is reported for the preparation of colloidal dispersions of string-bean-like anisotropic titania nanoparticles using arginine. These titania nanoparticles have a single-crystalline anatase structure and possess high surface area, which is advantageous for potential functional materials.

Anti-inflammatory effects of Rubus coreanus Miquel through inhibition of NF-κB and MAP Kinase.

BACKGROUND/OBJECTIVESRubus Coreanus Miquel (RCM), used as a traditional Korean medicine, reduces chronic inflammatory diseases such as cancer and rheumatoid arthritis. However, its mechanism has not been elucidated. In this study, we examine the anti-inflammatory effects of RCM and their possible mechanisms using RAW 264.7 cells.MATERIALS/METHODSUnripe RCM ethanol extract (UE), unripe RCM water extract (UH), ripe RCM ethanol extract (RE), and ripe RCM water extract (RH) were prepared. Inflammatory response was induced with LPS treatment, and expression of pro-inflammatory mediators (iNOS, COX-2, TNF-α, IL-1β, and IL-6) and NO and PGE2 productions were assessed. To determine the anti-inflammatory mechanism of RCM, we measured NF-κB and MAPK activities.RESULTSUE and UH treatment significantly reduced NF-κB activation and JNK and p38 phosphorylation and reduced transcriptional activities decreased iNOS, COX-2, and pro-inflammatory cytokines expressions, and NO and PGE2 productions. RE and RH treatments reduced IL-1β and IL-6 expressions through suppressions of JNK and p38 phosphorylation.CONCLUSIONSIn this study, we showed that RCM had anti-inflammatory effects by suppression of pro-inflammatory mediator expressions. Especially, unripe RCM showed strong anti-inflammatory effects through suppression of NF-κB and MAPK activation. These findings suggest that unripe RCM might be used as a potential functional material to reduce chronic inflammatory responses.

미숙과와 성숙과 복분자의 섭취가 복강 Macrophages의 유전자 발현에 미치는 영향

ABSTRACT Rubus coreanus Miquel (RCM) has been used as one of the Korean traditional medicines for prostate health. In addition, recent studies have reported that RCM reduced chronic inflammatory diseases such as cancer, and rheumatoid arthritis. Therefore, in this study, we investigated the effects of unripe and ripe RCM on inflammation- related gene expressions in LPS-stimulated mouse peritoneal macrophages. Mice were fed with 2% unripe RCM (U2), 10% unripe RCM (U10), 2% ripe RCM (R2), and 10% ripe RCM (R10) for 8 weeks. Peritoneal macrophages were isolated and stimulated with LPS then proinflammatory mediators (TNF-α, IL-1β, and IL-6), and prostaglandin E 2 (PGE 2 ) productions were assessed. Moreover, gene expression profiles were analyzed by cDNA microarray method. Unripe and ripe RCM significantly reduced TNF-α production but only unripe RCM decreased IL-1β and IL-6 production. RCM intake significantly reduced inflammatory-related gene expressions such as arachidonate 5-lip-oxygenase, interleukin 11, and nitric oxide synthase 2. Furthermore, unripe and ripe RCM significantly decreased ceruloplasmin, tissue plasminogen activator, thrombospondin 1, and vascular endothelial growth factor A expression which modulates symptoms of chronic inflammatory diseases. RCM intake also significantly increased hypoxia inducible factor 3, alpha which is the negative regulators of hypoxia-inducible gene expression. Furthermore, only unripe RCM reduced chemokine (C-C motif) ligand 8, chemokine (C-X-C motif) ligand 14, and phospholipase A2 expression. In this study, we showed that RCM had anti-inflammatory effects by suppression of pro-inflammatory mediator ex-pressions and may reduce chronic inflammatory disease progress through regulation of gene expressions. These findings suggest that RCM might be used as a potential functional material to reduce chronic inflammatory responses.

Hydrothermal evolution, optical and electrochemical properties of hierarchical porous hematite nanoarchitectures.

Hollow or porous hematite (α-Fe2O3) nanoarchitectures have emerged as promising crystals in the advanced materials research. In this contribution, hierarchical mesoporous α-Fe2O3 nanoarchitectures with a pod-like shape were synthesized via a room-temperature coprecipitation of FeCl3 and NaOH solutions, followed by a mild hydrothermal treatment (120°C to 210°C, 12.0 h). A formation mechanism based on the hydrothermal evolution was proposed. β-FeOOH fibrils were assembled by the reaction-limited aggregation first, subsequent and in situ conversion led to compact pod-like α-Fe2O3 nanoarchitectures, and finally high-temperature, long-time hydrothermal treatment caused loose pod-like α-Fe2O3 nanoarchitectures via the Ostwald ripening. The as-synthesized α-Fe2O3 nanoarchitectures exhibit good absorbance within visible regions and also exhibit an improved performance for Li-ion storage with good rate performance, which can be attributed to the porous nature of Fe2O3 nanoarchitectures. This provides a facile, environmentally benign, and low-cost synthesis strategy for α-Fe2O3 crystal growth, indicating the as-prepared α-Fe2O3 nanoarchitectures as potential advanced functional materials for energy storage, gas sensors, photoelectrochemical water splitting, and water treatment.

Facile fabrication of TiO2-based composites with tunable properties and improved performance through a general and controllable method

TiO2-based composites with tunable properties and improved performance were synthesized by a general and controllable method in environmentally benign conditions. The particle size, phase transformation, and thermal stability of composites can be conveniently tuned through the adjustment of reaction parameters. This work demonstrates that this approach not only helps us to easily and unrestrictedly design composites with the desired properties but it also provides the possibility for a large scale screening of potential functional materials for the future synthesis of smart devices.

The Optimization of Synthesis Condition of ZnSe Nanocrystals

In biomineralization, self-organization of organic based templates provides scaffolding for the assembly of QDs materials. The host-guest relationship between these protein cages and the encapsulated material is based primarily on a complementary electrostatic interaction. Zinc selenide (ZnSe) were synthesized in the cavity of the apoferritin from horse spleen (HsAFr) and the reaction condition was optimized by adding tween 20 to avoid ferritin agglomeration. The obtained nanodots were characterized by TEM, and absorption measurements. In addition, the protein concentration of ZnSe-ferritin was precisely measured by the Bradford protein assay method. From the results, it was concluded that the ZnSe nanocrystals were successfully synthesized in the core of ferritin and it can be applied as a potential functional material such as transistors, biosensor materials or medical imaging.

Hierarchical plasmonic-metal/semiconductor micro/nanostructures: green synthesis and application in catalytic reduction of p-nitrophenol

Hierarchical micro/nano arrays can offer both the advantages of nano-sized building blocks and micro- or submicrometer-sized ordered arrays, therefore representing one kind of potential functional materials and having received enormous attention for a wealth of applications. In this study, four-dimensionally flower-like CuO micro/nanostructures decorated by Au nanoparticles are synthesized via an environmentally friendly route assisted by polyethylene glycol. Experiments reveal that the product demonstrates high catalytic performance for the reduction of 4-nitrophenol using NaBH4 as the reducing agent, which could be attributed to the rich Au/CuO interfaces in the samples. Compared to the pure noble metal catalysts, the obtained sample is quite economic. In terms of methodology and cost-effectiveness, this study proposes an economically useful and green method to produce a highly efficient metal-based catalyst. It is also a good example for the organic combination of green chemistry and functional materials.

Phenolic compounds and antioxidant activities of Rumex hastatus D. Don. leaves

In this study different solvent fractions (n-hexane, ethyl acetate, chloroform, butanol and aqueous) of the methanol extract of Rumex hastatus(RH) leaves were evaluated for antioxidant activities. The ethyl acetate fraction possessed high amount of total polyphenolics (106.3±3.93 mg GAE/g extract) while butanolic fraction was found with high flavonoid contents (59.8±1.94 mg RTE/g extract) as compared to other solvent fractions. Butanol fraction exhibited most promising DPPH (EC50 140±0.99 μg/ml), iron chelation (EC50 70±2.1 μg/ml) and for phosphomolybdate (EC50 31±1.25 μg/ml) scavenging activity. However, ethyl acetate fraction exhibited the highest scavenging potential for super oxide radicals (EC50 40±0.78 μg/ml), ABTS radicals (EC50 70±2.46 μg/ml), hydroxyl radicals (EC50 9±0.56 μg/ml) and inhibition of β-carotene linoleic acid peroxidation (EC50 54±5.67 μg/ml). Chloroform fraction showed the most potent antioxidant activities in scavenging of hydrogen peroxide (EC50 48±4.89 μg/ml). The high correlation coefficient was found between EC50 values of DPPH, superoxides, hydroxyl, hydrogen peroxide and ABTS radicals with total polyphenolic and flavonoids. HPLC studies of ethyl acetate fraction indicated the presence of luteolin (24.67±2.90 mg/g extract), kaempherol (17.03±1.67 mg/g extract), luteolin-7-O-glucoside (14.73±2.17 mg/g extract) and rutin (8.24±1.43 mg/g extract). Therefore, our study substantiated that RH leaves can be used as a good source of potential antioxidant or functional food material due to the presence of sufficient amount of phenolics such as luteolin and kaempherol. Key words: Rumex hastatus, antioxidant activity, flavonoids, phenolics, 2,2-diphenyl-1-picrylhydrazyl.

Optimized ultrasonic-assisted extraction of flavonoids from Prunella vulgaris L. and evaluation of antioxidant activities in vitro

Abstract The Box–Behnken design combined with response surface methodology was used to optimize ultrasonic-assisted extraction of total flavonoids from Prunella vulgaris L. The results indicated that the highest extraction yield of flavonoids by ultrasonic-assisted extraction could obtain to be 3.62% using ethanol concentration of 41% (v/v) as solvent and liquid to solid ratio of 30:1 (mL/g) for 30.5 min at the temperature of 79 °C. The crude extract was then purified by AB-8 macroporous adsorption resin, the flavonoids content in the purified extract increased to 81.58%. The antioxidant activities of the purified flavonoids were evaluated in vitro by scavenging capability of DPPH free radical and hydroxyl free radical, reducing power, total antioxidant capability and β-carotene bleaching test. The results showed that the flavonoids have significant antioxidant activities, which can be used as a source of potential antioxidant. Industrial Relevance The effective exploitation and application of the natural plant resources have very important significance for the industrial and economic development. Prunella vulgaris L. is a perennial plant commonly found in China and Europe, which was proved to be rich in flavonoids, triterpenes and phenolic acid. It has long been used as a folk medicine for alleviating sore throat, reducing fever and accelerating wound healing. Recent studies have demonstrated that the methanol or water extract of this herb exhibits many of the activities including antihyperglycemic activity, systemic anaphylaxis inhibition, antioxidative antiviral and antibacterial effects. However, attempts have not been made so far to investigate the ultrasonic-assistant extraction of flavonoids from P. vulgaris L. and evaluate their antioxidant activities in vitro. In this work, a four-variable, three-level experiment Box–Behnken design based on response surface methodology was used to optimize ultrasonic-assistant extraction of flavonoids from P. vulgaris L. The optimized results showed that the highest extraction yield of flavonoids by ultrasonic-assisted extraction could arrive 3.62%, using 41% (v/v) ethanol as solvent and 30:1 (mL/g) liquid to solid ratio for 30.5 min at the temperature of 79 °C. The suitability of the model equation for predicting the optimum response values was tested using the selected optimal conditions. The predicted extraction yield of flavonoids was 3.63%, which was consistent with the practical extraction yield of flavonoids of 3.62%. The crude extract was then purified by AB-8 macroporous adsorption resin, the flavonoids content in the purified extract increased to 81.58%. The antioxidant activities of the purified flavonoids were evaluated in vitro by scavenging capability of DPPH free radical and hydroxyl free radical, reducing power, total antioxidant capability and β-carotene bleaching test. The results indicated that the flavonoids have significant antioxidant activities, which can be used as a source of potential antioxidant or functional food material. We believe that the knowledge gained from this study should be helpful to further exploit and apply this resource .

Evaluation of antioxidant activities of various solvent extracts of Carissa opaca fruits

The chloroform and aqueous fractions of Carissa opaca fruit, a traditional medicinal fruit in Pakistan possessed a high amount of total phenolic and flavonoid contents as compare to other solvent fractions with potent antioxidant activities in scavenging DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, and had strong iron chelating activity. On the other hand, the ethyl acetate fraction showed the highest inhibition of β-carotene linoleic acid peroxidation and phosphomolybdate assay. A high correlation coefficient existed between EC 50 values of DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, total phenolics and flavonoids, but a non significant correlation was found in the case of iron chelaters, β-carotene and phosphomolybdate assay. This study verified that the chloroform and aqueous fractions have strong antioxidant activities which were correlated with its high level of phenolics and flavonoids. These fractions can be used as a source of potential antioxidant or functional food material.

Tunable Electronic Structures and Optical Properties of Fluorenone-Based Molecular Materials by Heteroatoms

The ground-state and excited-state electronic structures as well as the tunable optical properties of a variety of newly designed fluorenone-based molecular materials have been theoretically investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The substitutes on the O atom in the carbonyl group of the fluorenone (FN) molecule with S (FN-C=S), Se (FN-C=Se), and Te (FN-C=Te) atoms can significantly influence their electronic structures, molecular orbitals, geometric conformations, and optical properties of fluorenone-based molecular materials. Due to the important difference of electronegativity for O, S, Se, and Te atoms in the same group, the ground-state dipole moment of these fluorenone-based molecular materials is gradually decreased in the order FN, FN-C=S, FN-C=Se, and FN-C=Te. At the same time, the ground-state bond length of the C=X (X refers O, S, Se, and Te) is gradually increased in the order of FN, FN-C=S, FN-C=Se, and FN-C=Te. Due to the different nature of the S(1) state for FN (pipi* character) and FN-C=S, FN-C=Se, and FN-C=Te (sigmapi* character), the excited-state dipole moment of FN in the S(1) state is dramatically increased in comparison with that in the ground state; however, the excited-state dipole moments of FN-C=S, FN-C=Se, and FN-C=Te are significantly diminished. In addition, the excited-state bond length of C=X (X refers O, S, Se, and Te) in the S(1) state is lengthened in comparison with that in the ground state due to the photoexcitation of the C=X bond FN, FN-C=S, FN-C=Se, and FN-C=Te. On the other hand, the energy level of the HOMO orbital is heightened and that of LUMO orbital is lowered with the introduction of heteroatoms in the order of S, Se, and Te. Consequently, the energy gap between LUMO and HOMO orbtials is gradually decreased in the order of the FN, FN-C=S, FN-C=Se, and FN-C=Te. Consequently, the calculated fluorescence wavelengths are strongly red-shifted from the visible region for FN to the near-infrared (NIR) region for FN-C=S, FN-C=Se, and FN-C=Te. These newly designed fluorenone-based molecules may be potential NIR fluorescent molecular functional materials.

Moisture-saturated zeolites – A new strategy for releasing nitric oxide

To cure ulcers inside the stomach and/or intestines caused by bacterial infection, a new strategy for releasing NO in the digestive system is proposed and verified. Nitric oxide, pre-adsorbed onto zeolite, when added to hydrochloric acid with a low pH (similar to that of gastric juice), releases NO into the solution; the amount of NOx released can be tuned by altering the structure and modifier species of the zeolite. Various factors, including pH value, the temperature of acid solution, the volume ratio of liquid to solid, and the release time, are investigated to provide help understand the NOx release mechanism from the moisture-saturated zeolites. We find that nitrite is produced in acid solution, which has advantages for controlled NO release because it provides an active storage mechanism for NO, and this is proved by in situ FT-IR experiments. Finally, we were able to simultaneously achieve the release of a large amount of NO and the capturing of nitrosamine by alumina-modified zeolite samples in the gastric juice mimic, affording a potential functional material to reduce the risk of ulcers and cancers in the digestive system.

A Collagen-Mimic Dendrimer Capable of Controlled Release

A collagen model peptide-attached dendrimer was synthesized as a potential functional collagen material. The peptides that clustered at the surface of the dendrimer formed a thermally reversible collagen-like triple helix. This dendrimer worked as a drug carrier with thermosensitive release capabilities, although it did not exhibit a lower critical solution temperature. From this dendrimer, the hydrogel could be made at low temperature.