Organic-inorganic Hybrid Nanostructures Research Articles

Organic-Inorganic Hybrid Nanoflowers as Potent Materials for Biosensing and Biocatalytic Applications

Flower-shaped organic-inorganic hybrid nanostructures, termed nanoflowers, have received considerable recent attention as they possess greatly enhanced activity, stability, durability, and even selectivity of entrapped organic biomolecules, which are much better than those from the conventional methods. They can be synthesized simply via co-incubation of organic and inorganic components in aqueous buffer at room temperature and yield hierarchical nanostructures with large surface-to-volume ratios, allowing for low-cost production by easy scale-up, as well as the high loading capacity of biomolecules without severe mass transfer limitations. Since a pioneering study reported on hybrid nanoflowers prepared with protein and copper sulfate, many other organic and inorganic components, which endow nanoflowers with diverse functionalities, have been employed. Thanks to these features, they have been applied in a diverse range of areas, including biosensors and biocatalysis. To highlight the progress of research on organic-inorganic hybrid nanoflowers, this review discusses their synthetic methods and mechanisms, structural and biological characteristics, as well as recent representative applications. Current challenges and future directions toward the design and development of multi-functional nanoflowers for their widespread utilization in biotechnology are also discussed.

Biomineralized hybrid nanoparticles for imaging and therapy of cancers.

In this review, we describe the research trends of hybrid nanocarriers developed based on a biomimetic mineralization process, and their recent applications in imaging and therapy of cancers. Organic-inorganic hybrid nanostructures formed by diverse biomimetic mineralization approaches are briefly reviewed, and particularly, the biomedical applications of these hybrid nanocarriers for the diagnosis and therapy of cancers are discussed. Biomineralization is an important process in which living organisms produce biominerals, such as calcium phosphate (CaP), calcium carbonate (CaCO3), and silica (SiO2), to strengthen their tissues, as found in the formation of bone and teeth. Introducing the artificial biomimetic mineralization process to nanobiotechnology has inspired researchers to develop smart stimuli-responsive nanoparticles for multiple purposes, such as improved therapeutic activity and activatable imaging of cancers.

유-무기 혼성 나노 꽃의 생물공학적 응용 연구 동향

Organic-inorganic hybrid nanostructures with flower-like morphology, so called nanoflowers, have received an increasing attention due to their capability to greatly enhance the activity, stability, and durability of entrapped biomolecules, which is much better than those from the conventional immobilization strategies. These hybrid nanoflowers are simply synthesized via the incubation at room temperature but show high surface roughness and large surface-tovolume ratio, which enables high loading capacity of biomolecules without severe mass transfer limitation. Based on the advantageous features, they have been applied in the field of biotechnology such as biosensor, biofuel cell, and protein digestion. To highlight the research progress on organic-inorganic hybrid nanoflowers, this review discusses the synthetic methods, structural characteristics, and recent applications of the nanoflowers. Finally, we address the future prospects of the hybrid nanoflowers in biotechnology industry, particularly for sensing, medicine, and catalyst.

“Precipitation on Nanoparticles”: Attractive Intermolecular Interactions Stabilize Specific Ligand Ratios on the Surfaces of Nanoparticles

AbstractConfining organic molecules to the surfaces of inorganic nanoparticles can induce intermolecular interactions between them, which can affect the composition of the mixed self‐assembled monolayers obtained by co‐adsorption from solution of two different molecules. Two thiolated ligands (a dialkylviologen and a zwitterionic sulfobetaine) that can interact with each other electrostatically were coadsorbed onto gold nanoparticles. The nanoparticles favor a narrow range of ratios of these two molecules that is largely independent of the molar ratio in solution. Changing the solution molar ratio of the two ligands by a factor of 5 000 affects the on‐nanoparticle ratio of these ligands by only threefold. This behavior is reminiscent of the formation of insoluble inorganic salts (such as AgCl), which similarly compensate positive and negative charges upon crystallizing. Our results pave the way towards developing well‐defined hybrid organic–inorganic nanostructures.

Controlled release of organic-inorganic nanohybrid:cefadroxil intercalated Zn-Al-layered double hydroxide.

BackgroundThe intercalation of an antibiotic drug, cefadroxil (CD), into the inter-gallery of Zn, Al nitrate-layered double hydroxide (LDH) was accomplished using a co-precipitation method. This formed a nanostructured organic–inorganic hybrid material that can be exploited for the preparation of a controlled release formulation.Materials and methodsThe drug–LDH nanohybrid was characterized by using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) thermogravimetric (TG) analysis, X-ray powder diffraction (XRD) and UV–visible (UV–vis) absorption spectroscopy, which confirmed the intercalation process. Release tests of nanohybrid in the presence or absence of NaCl or poly-acrylamide (PAM) were performed in vitro in gastric (pH 1.2), lysosomal (pH 4.0), intestinal (pH 6.8) and blood (pH 7.4) simulated fluid using UV–vis spectroscopy.ResultsAt pH 1.2, LDH was dissolved and intercalated antibiotic released from ZnAl-CD in a molecular form, which led to a significant increase in the antibiotic’s solubility. Results showed that the release of drug from nanohybrid at pH 4.0, 6.8 and 7.4 was a sustained process.ConclusionThis material might reduce side effects by the release of the drug in a controlled manner. However, it was found that the presence of Cl or PAM species in the release media has a negative impact on the release behavior. The weathering mechanism is responsible for the release of CD from the nanocomposite at pH 1.2, while the mechanism of anion exchange may be responsible for the release behavior at pH 4.0, 6.8 and 7.4. A number of kinetic models were chosen to gain more insights into the mechanisms of drug release. At pH 1.2, the zero-order model most satisfactorily explained the release kinetics of CD, while the release data of CD at pH 4.0, 6.8 and 7.4 were governed by Bhaskar kinetics.

Porous core-shell N-doped Mo2C@C nanospheres derived from inorganic-organic hybrid precursors for highly efficient hydrogen evolution

Using inorganic-organic MoO42−/aniline-pyrrole (MoO42−-Polymer) hybrids nanospheres as precursors, we synthesize the porous core-shell N-doped Mo2C@C nanospheres with the three advantages including porous nanostructures, conductive substrate and N-doping, which may maximize the activity of electrocatalysts for hydrogen evolution reaction (HER). The as-prepared Mo2C@NC has the porous core-shell nanospherical structure with ultrafine Mo2C nanoparticles as core and ultrathin N-doped carbon (NC) nanolayers as shell. The aniline-pyrrole in MoO42−-Polymer prevents fast growth and severe aggregation of Mo2C and form porous structure composed of ultrafine Mo2C, which implies the more exposed active sites. On the other hand, the carbonization of MoO42−-Polymer produces the ultrathin N-doped carbon shell on the surface of Mo2C@NC nanospheres, which can optimize electronic structures and greatly improve charge transfer rate. Through varying MoO42− content and carbonization temperature, the optimized Mo2C@NC sample exhibits enhanced HER performance and long-time stability both in acidic and alkaline solution. It requires an onset potential of only 110 mV and 60 mV, striking kinetic metrics (Tafel slope: 83 mV dec−1 and 70 mV dec−1) in 0.5 M H2SO4 and in 1 M KOH, respectively. Therefore, designing unique inorganic-organic hybrid nanostructures may open up a new way for excellent electrocatalysts for HER.

Organic-inorganic hybrid nanomaterials for advanced light dependent resistors

We report the photoconduction behaviour of hybrid organic (polypyrrole) - inorganic (ZnO) nanostructures, synthesized by the surfactant mediated solution based chemical method at room temperature, for the energy saving light dependent resistor (LDR) applications. The formation of organic-inorganic hybrid nanostructures is confirmed by the combination of high resolution transmission electron microscopy and scanning electron microscopy, which revealed creation of cubical shaped wurtzite ZnO nanoparticles with different preferential orientations and transformation of clip-like nanofibres form of pure polypyrrole (PPy) into worm-like nanoribbons having embedded ZnO nanoparticles in it. Given p-type nature of PPy and n-type nature of ZnO, the embedment of ZnO nanoparticles in PPy is expected to create several localized discrete p-n junctions, which is why Raman spectroscopic results reveal the change in molecular structure of PPy due to its nanoscale interaction with ZnO. The photoresponse of PPy is found to continuously enhance from ∼4.5 to 10.7% with increase in ZnO concentration from 0 to 10% at the constant illumination intensity of 100 mW/cm2. The improved photoresponse can be attributed to the formation of localized p-n junctions (p-type PPy/n-type ZnO) in the structure. The photoresponse of PPy and its nanocomposites also increases with increase in illumination intensity from 30 to 100 mW/cm2, which is attributed to the increased number of photo-generated electron-hole pairs.

Controlled Construction of Nanostructured Organic–Inorganic Hybrid Material Induced by Nanocellulose

Sticky rice lime mortar (SRLM) is a widely used lime-based gelled material in ancient China. Sticky rice plays an important role in the formation of organic–inorganic hybrid material. Inspired by this, a nanostructured organic–inorganic hybrid material (NOHM) was constructed based on the regulation of nanocellulose (NCC) on the crystallization of calcium carbonate. The used NCC was prepared by a green way via simultaneous ball milling and phosphotungstic acid catalyzed hydrolysis. The characteristics of the prepared NOHM were explored to gain insight into the interaction of NCC and mineral during the mineralization of calcium carbonate. The results indicate that nanocellulose plays a crucial role in the formation of nanostructured organic–inorganic hybrid material, which not only induces and regulates the mineralization process of calcium carbonate crystals but also affects the morphology and size of the formed calcium carbonate crystals. The mechanical strength and durability of NOHM were significantly i...

Near band gap luminescence in hybrid organic-inorganic structures based on sputtered GaN nanorods

Novel hybrid organic-inorganic nanostructures fabricated to utilize non-radiative resonant energy transfer mechanism are considered to be extremely attractive for a variety of light emitters for down converting of ultaviolet light and for photovoltaic applications since they can be much more efficient compared to devices grown with common design. Organic-inorganic hybrid structures based on green polyfluorene (F8BT) and GaN (0001) nanorods grown by magnetron sputtering on Si (111) substrates are studied. In such nanorods, stacking faults can form periodic polymorphic quantum wells characterized by bright luminescence. In difference to GaN exciton emission, the recombination rate for the stacking fault related emission increases in the presence of polyfluorene film, which can be understood in terms of Förster interaction mechanism. From comparison of dynamic properties of the stacking fault related luminescence in the hybrid structures and in the bare GaN nanorods, the pumping efficiency of non-radiative resonant energy transfer in hybrids was estimated to be as high as 35% at low temperatures.

PA17 異方場における液晶相転移を利用した有機-無機複合ナノ構造の垂直配向制御と機能化(液晶化学材料,ポスター発表,2015年日本液晶学会討論会)

PA17 異方場における液晶相転移を利用した有機-無機複合ナノ構造の垂直配向制御と機能化(液晶化学材料,ポスター発表,2015年日本液晶学会討論会)

Size of CdTe Quantum Dots Controls the Hole Transfer Rate in CdTe Quantum Dots–MEHPPV Polymer Nanoparticle Hybrid

Design of light harvesting systems using inorganic–organic hybrid nanostructures is an emerging field of research. Here, we design hybrid nanostructures by using electrostatic attraction of negatively charged CdTe QDs with positively surface functionalized poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) polymer nanoparticles for developing an efficient light harvesting system. Interfacial charge transfer between QDs and polymer nanoparticles has been investigated by ultrafast spectroscopy which is crucial for designing an efficient light harvesting system. Interfacial charge transfer dynamics are being controlled by tuning the size of QDs which is eventually controlled by highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) levels of QDs. Femtosecond fluorescence upconversion and transient absorption spectroscopic studies reveal that the hole transfer process takes place from QDs to polymer nanoparticles and the rate of hole transfer process is size depen...

Controlled preparation of ZnS nanoparticle arrays in Langmiur monolayer of an unsymmetrical phthalocyaninato zinc complex: Synthesis, organization and semiconducting properties

A new unsymmetrical phthalocyaninato zinc complex with typical amphiphilic nature, namely 2,3-di(4-hydroxyphenoxy)-9,10,16,17,24,25-hexakis([Formula: see text]-octyloxy)phthalocyaninato zinc, Zn[Pc(OC8H[Formula: see text](OPhOH)2], has been designed, synthesized, and characterized by a range of spectroscopic methods. The Langmuir monolayer of this amphiphilic complex has been used as not only an organic template but also as a good functional organic material to produce the monodispersed nanoparticles of Zn[Pc(OC8H[Formula: see text](OPhOH)2]/ZnS nanocomposite. In addition, multilayer pure and hybrid films have also been obtained by depositing monolayers of the amphiphilic complex and Zn[Pc(OC8H[Formula: see text](OPhOH)2]/ZnS nanocomposite, respectively, using the Langmuir–Shäfer (LS) method. Surface pressure-area isotherms, UV-vis spectroscopic, and XRD studies indicate that the molecules adopted a face-to-face configuration and edge-on orientation in both the multilayer pure LS and Zn[Pc(OC8H[Formula: see text](OPhOH)2]/ZnS hybrid films. In particular, current–voltage (I–V) measurements reveal the superior conductivity of the Zn[Pc(OC8H[Formula: see text](OPhOH)2]/ZnS hybrid film nanocomposites to that of the stand-alone films, and this is due to the existence of the densely packed molecular architecture in the film matrix and the large interfacial area between the two components. These characteristics remove the charge transporting bottleneck by creating an interpenetrating consistent thin film of hybrid materials. The result sheds lights on new ways for developing organic-inorganic hybrid nanostructures with good semiconducting properties.

A new generation approach in enzyme immobilization: Organic-inorganic hybrid nanoflowers with enhanced catalytic activity and stability.

Many different micro and nano sized materials have been used for enzymes immobilization in order to increase their catalytic activity and stability. Generally, immobilized enzymes with conventional immobilization techniques exhibit improved stability while their activity is lowered compared to free enzymes. Recently, an elegant immobilization approach was discovered in synthesis of flower-like organic-inorganic hybrid nanostructures with extraordinary catalytic activity and stability. In this novel immobilization strategy, proteins (enzymes) and metal ions acted as organic and inorganic components, respectively to form hybrid nanoflowers (hNFs). It is demonstrated that the hNFs highly enhanced catalytic activities and stability in a wide range of experimental conditions (pHs, temperatures and salt concentration, etc.) compared to free and conventionally immobilized enzymes. This review mainly discussed the synthesis, characterization, development and applications of organic-inorganic hybrid nanoflowers formed of various enzymes and metal ions and explained potential mechanism underlying enhanced catalytic activity and stability.

Preparation of LaF3:Eu3+ Based Inorganic-Organic Hybrid Nanostructures via an Ion Exchange Method and Their Strong Luminescence.

Lanthanide doped inorganic-organic hybrid nanostructures have received much attention in recent years due to their strong luminescence sensitized by organic ligands via an energy transfer route. In this work, an ion exchange method was used to prepare Eu3+ doped LaF3 based inorganic-organic hybrid nanostructures with organic ligands. The undoped LaF3 nanoparticles were first synthesized by a hydrothermal method, and Eu3+ ions were then ion exchanged into these LaF. nanoparticles to form the Eu3+ doped LaF3 nanoparticles, which were then used to prepare the inorganic-organic hybrid nanostructures with benzoic acid and 2-thenoyltrifluoroacetone. As a result of the luminescence sensitization, strong luminescence was observed in these inorganic-organic hybrid nanostructures, and the luminescence enhancement was over 40 times. Dependence of the luminescence of the hybrid nanostructures on the doping concentration and amount of organic ligands was studied in detail, and optimization was conducted to obtain the maximum luminescence for the hybrid nanostructures.

Formation of CdS in Supramolecular Dendrimer–Dye Assemblies: Electrostatic and Electrostatic-Coordination Templating

A novel concept for the formation of organic–inorganic hybrid nanostructures based on a tunable supramolecular templating mechanism involving several types of noncovalent interactions is presented. Different organic–inorganic hybrid structures with narrow size distributions composed of a cationic dendrimer, an oppositely charged divalent diazo dye, and CdS can be created: First, larger supramolecular structures consisting of several 100 to 1000 dendrimers is built based on ionic and π–π interaction. Second, with this self-assembled template, the hybrid nanostructure forms based on electrostatics and coordination interaction. The influence on shape and internal structure of the supramolecular hybrid architectures was investigated. A size control of the assemblies is possible in a range of 60–420 nm. The prospect to direct self-assembly and templating through the controlled combination of different noncovalent interactions potentially allows to create tailor-made systems for various applications.

An Interfacial Europium Complex on SiO2 Nanoparticles: Reduction-Induced Blue Emission System.

In this study, Eu-coated SiO2 nanoparticles have been prepared, consisting of an interfacial complex of Eu and 1,10-phenanthroline (phen) at the solid surfaces of the SiO2/Eu nanostructures. The as-prepared SiO2/Eu/phen nanoparticles exhibits sharp red emission via energy transfer from the phen to the EuIII. After sintering at 200 °C in air, the emission is tuned from red to blue. The blue emission is originated from EuII. This reduction-induced emissive phenomenon resulted from the electron-donating environment created by the surrounding phen and SiO2, which is the first reported fabrication of a stable EuII-based emissive material using mild conditions (reaction in air and at low temperature) and an organic-inorganic hybrid nanostructure. The existence of two different stable oxidation states with characteristic emissions, blue emissive EuII and red emissive EuIII, suggests significant potential applications as novel luminescent materials with inorganic-organic hybrid structures.

Twin Polymerization--a New Principle for Hybrid Material Synthesis.

Twin polymerization is a novel modular approach for the synthesis of hybrid materials. Using this strategy two distinct polymers of either inorganic or organic nature are produced from a single source monomer in a mechanistically coupled process. Twin polymerization is an elegant way for producing nanostructured organic-inorganic hybrid materials of composition and morphology on demand. The main objective of this Review is the explanation of the principle of various twin polymerization processes and their appropriate terminologies. Different types of twin polymerization are classified with respect to the underlying processes as described in individual examples, demonstrating its potential in material synthesis. Prospects of the synthetic methodology of twin polymerization are demonstrated for different molecular structures of twin monomers and the resulting hybrid materials. A comparison with other scenarios for the synthesis of two different polymers within one procedure is included.

The impact of ultra-low amounts of amino-modified MMT on dynamics and properties of densely cross-linked cyanate ester resins.

Thermostable nanocomposites based on densely cross-linked cyanate ester resins (CER), derived from bisphenol E and doped by 0.01 to 5 wt. % amino-functionalized 2D montmorillonite (MMT) nanoparticles, were synthesized and characterized using Fourier transform infrared (FTIR), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDXS), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), far-infrared (Far-IR), and creep rate spectroscopy (CRS) techniques. It was revealed that ultra-low additives, e.g., 0.025 to 0.1 wt. %, of amino-MMT nanolayers covalently embedded into СER network exerted an anomalously large impact on its dynamics and properties resulting, in particular, in some suppression of dynamics, increasing the onset of glass transition temperature by 30° to 40° and twofold rise of modulus in temperature range from 20°C to 200°C. Contrarily, the effects became negligibly small or even negative at increased amino-MMT contents, especially at 2 and 5 wt. %. That could be explained by TEM/EDXS data displaying predominance of individual amino-MMT nanolayers and their thin (2 to 3 nanolayers) stacks over more thick tactoids (5 to 10 nanolayers) and the large amino-MMT aggregates (100 to 500 nm in thickness) reversing the composite structure produced with increasing of amino-MMT content within CER matrix. The revealed effect of ultra-low amino-MMT content testifies in favor of the idea about the extraordinarily enhanced long-range action of the ‘constrained dynamics’ effect in the case of densely cross-linked polymer networks.PACS82.35.Np Nanoparticles in polymers; 81.05.Qk Reinforced polymers and polymer-based composites; 81.07.Pr Organic-inorganic hybrid nanostructures

Nonaqueous Synthesis of a Bismuth Vanadate Photocatalyst By Using Microwave Heating: Photooxidation versus Photosensitized Decomposition in Visible‐Light‐Driven Photocatalysis

AbstractA new synthetic route to monoclinic bismuth vanadate using a concept adapted from a nonaqueous synthesis strategy for nanostructured organic–inorganic hybrid materials and metal oxides, introduced recently as twin polymerization, is reported. Microwave‐assisted synthesis starting from bismuth(III) tert‐butoxide and vanadium(V) oxytri(tert‐butoxide) in the presence of 2‐methoxybenzyl alcohol, 2,4‐dimethoxybenzyl alcohol, and 2‐(2‐thienyl)iso‐propyl alcohol gave hybrid materials, which were characterized by solid‐state 13C NMR spectroscopy, CH analysis, atomic absorption spectroscopy, and energy dispersive X‐ray spectroscopy. Subsequent pyrolysis resulted in nanoscale monoclinic bismuth vanadate that showed a high photocatalytic activity. The photocatalytic decomposition of model pollutants such as rhodamine B (RhB), methyl orange, methylene blue, and orange G under visible‐light irradiation using the as‐prepared bismuth vanadate samples was studied with a focus on the influence of the agglomeration behavior. The interplay between the photooxidation of RhB, induced by the excitation of the catalyst using visible light, and the photosensitized decomposition pathway is demonstrated by degradation experiments in solution and the solid state.

Hybrid ZnO-Based Nanoconjugate for Efficient and Sustainable White Light Generation

Developing new ways of generating white light is of paramount importance for the design of the next generation of smart, energy-efficient lighting sources. Here we report tunable white light emission of hybrid organic–inorganic nanostructures based on colloidal ZnO nanocrystals conjugated with organic fluorophores. These materials act as single nanophosphors owing to the distance-dependent energy transfer between the two components. The defect-based size-tunable ZnO nanocrystal blue-green emission coupled with complementary color emission from different fluorophores allows for the generation of white light with targeted chromaticity, color temperature, and color rendering index. We further show that silane layer-protected nanoconjugates result in increased stability of white light emission over a long period of time. The results of this work demonstrate an inexpensive, green, and sustainable approach to general solid-state lighting, without the use of rare earth or heavy metals. Colloidal form of the repo...