Synthesis Of Inorganic Nanomaterials Research Articles

Two-dimensional collagen-graphene as colloidal templates for biocompatible inorganic nanomaterial synthesis.

In this study, natural graphite was first converted to collagen-graphene composites and then used as templates for the synthesis of nanoparticles of silver, iron oxide, and hydroxyapatite. X-ray diffraction did not show any diffraction peaks of graphene in the composites after inorganic nucleation, compared to the naked composite which showed (002) and (004) peaks. Scanning electron micrographs showed lateral gluing/docking of these composites, possibly driven by an electrostatic attraction between the positive layers of one stack and negative layers of another, which became distorted after inorganic nucleation. Docking resulted in single layer-like characteristics in certain places, as seen under transmission electron microscopy, but sp2/sp3 ratios from Raman analysis inferred three-layer composite formation. Strain-induced folding of these layers into uniform clusters at the point of critical nucleation, revealed beautiful microstructures under scanning electron microscopy. Lastly, cell viability studies using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed the highest cell viability for the collagen-graphene-hydroxyapatite composites. In this manner, this study provided – to the field of nanomedicine – a new process for the synthesis of several nanoparticles (with low toxicity) of high interest for numerous medical applications.

Novel Synthesis Strategy of γ-AlOOH Nanotubes: Coupling Reaction via Ionic Liquid-Assisted Hydrothermal Route

A novel synthetic strategy, i.e., transition metal ions used to drive a coupling reaction in terms of complex formation of the metal ions and decomposition of a precursor, combined with ionic liquid-assisted hydrothermal route, was utilized to synthesize γ-AlOOH nanotubes with high purity and uniform dimension at a mild condition. These γ-AlOOH nanotubes can be easily transformed to γ-Al2O3 nanotubes by calcining at 600 °C for 2 h, without changing the morphology. More specifically, this strategy may be helpful to develop a new opportunity for synthesis of inorganic nanomaterials with novel morphologies and improved properties.

Synthesis of calcium phosphate nanoparticles in deep-eutectic choline chloride–urea medium: Investigating the role of synthesis temperature on phase characteristics and physical properties

A novel and green method based on precipitation of calcium phosphate reactants in a deep eutectic solvent (DES) was devised for the synthesis of calcium phosphate nanoparticles. The DES was prepared by simple mixing-heating of choline chloride and urea. The effect of synthesis temperature on particulate and structural properties of the synthesized calcium phosphate nanoparticles was examined by X-ray diffractometry, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and nitrogen adsorption techniques. Based on the results, increase of synthesis temperature from 25 to 150°C was associated with the gradual evolution of calcium-deficient apatite phase, however with a poor degree of crystallinity. The particle size and Ca/P molar ratio of precipitated calcium phosphate particles were also dependent of temperature so that they increased from 25 to 85nm and 1.10 to 1.27 when the synthesis temperature increased from 25 to 150°C. The synthesized particles were mesoporous regardless of the synthesis temperature. Given the advantages of DESs from both environmental and chemical points of view, the present study can provide a new direction for DES-assisted synthesis of inorganic nanomaterials and particularly nanobiomaterials.

ChemInform Abstract: The Art of Using Ionic Liquids in the Synthesis of Inorganic Nanomaterials

AbstractReview: 85 refs.

Designing Non‐Native Iron‐Binding Site on a Protein Cage for Biological Synthesis of Nanoparticles

In biomineralization processes, a supramolecular organic structure is often used as a template for inorganic nanomaterial synthesis. The E2 protein cage derived from Geobacillus stearothermophilus pyruvate dehydrogenase and formed by the self-assembly of 60 subunits, has been functionalized with non-native iron-mineralization capability by incorporating two types of iron-binding peptides. The non-native peptides introduced at the interior surface do not affect the self-assembly of E2 protein subunits. In contrast to the wild-type, the engineered E2 protein cages can serve as size- and shape-constrained reactors for the synthesis of iron nanoparticles. Electrostatic interactions between anionic amino acids and cationic iron molecules drive the formation of iron oxide nanoparticles within the engineered E2 protein cages. The work expands the investigations on nanomaterial biosynthesis using engineered host-guest encapsulation properties of protein cages.

Non-equilibrium dynamic control of gold nanoparticle and hyper-branched nanogold assemblies

A flow system capable of dynamically controlling the synthesis of inorganic nanomaterials in real time switching between different conditions is presented whereby the combination of reactor engineering, ligand design and the employment of two in-line analytical techniques enables the synthesis and rapid characterisation of gold nanoparticles. Furthermore, it has been possible to discover a new type of hyper-branched nanogold-based material directly based on the optical feedback from UV-Vis, without stopping the process and the nanoparticles have been characterised using TEM.

Phase transfer-based synthesis of HgS nanocrystals.

Phase transfer techniques possess remarkable advantages for the synthesis of inorganic nanomaterials. In contrast to the abundant reports on the preparation of noble metal nanoparticles using phase transfer, the number of semiconductor nanocrystals syntheses based on phase transfer techniques is still limited. Herein, we report a systematic study of the phase transfer-based synthesis of HgS nanocrystals, including the tuning of their morphology/shape by either solvent choice or temperature. This strategy involves the transfer of Hg(ii) ions from aqueous solution to toluene, oleic acid or oleylamine and subsequent sulfidation at room or elevated temperature. Furthermore, we have extended this phase-transfer based strategy to the fabrication of HgS-Au nanocomposites. The studies in this work might provide a facile route for producing HgS nanocrystals with desirable properties and offer an effective strategy to investigate the influence of the morphology of HgS on the physical/chemical properties of various HgS-based materials.

Enzyme mediated synthesis of water-dispersible, naturally protein capped, monodispersed gold nanoparticles; their characterization and mechanistic aspects

Inorganic nanomaterials are conventionally synthesized under harsh environments like extremes of temperature, pressure and pH. These methods are eco-unfriendly, expensive, toxic, cumbersome, yield bigger particles which agglomerate due to not being capped by capping agents. In contrast, biological synthesis of inorganic nanomaterials occurs under ambient conditions viz. room temperature, atmospheric pressure, physiological pH and is reliable, eco-friendly and cheap. We have already reported the extracellular biosynthesis of monodispersed gold nanoparticles from the whole cells of novel extremophilic actinomycete Thermomonospora sp. In order to know the exact mechanism of synthesis, we decided to investigating it further. Here we describe the simple protocol for purification of the temperature and SDS resistant sulfite reductase enzyme and organic capping molecule, which are required for the synthesis and stabilization of gold nanoparticles respectively. This purified enzyme was then employed for the synthesis of gold nanoparticles along with the capping molecule, which render gold nanoparticles monodispersed in solution.

The art of using ionic liquids in the synthesis of inorganic nanomaterials

Wet chemistry using ionic liquids as the medium has proven to be highly efficient for the preparation of several types of metallic, metal oxides, and other kinds of semiconductor nanostructures, and so on. This article reviews state-of-the-art research activities in the field, focusing on the use of ionic liquids as a versatile regent for the synthesis of various nanoparticle systems. We begin with a survey of choices to explore the ability of ionic liquids to act as a reactant, solvent, and surfactant, as a function of other synthesis parameters, also denoted as ionic liquid precursors (or task-special ionic liquids), which offer many advantages over traditional solution-phase methods. We then examine the design and fabrication of functional inorganic materials by means of optimizing the effect models of ionic liquids. Many of the most recent advances in ionothermal or ionic liquid-assisted synthesis have been realized by appropriate choice of cations or anions of ionic liquids according to the need. This review also highlights crucial issues that should be addressed in future research activities.

Understanding the Effect Models of Ionic Liquids in the Synthesis of NH4‐Dw and γ‐AlOOH Nanostructures and Their Conversion into Porous γ‐Al2O3

Well-dispersed ammonium aluminum carbonate hydroxide (NH4-Dw) and γ-AlOOH nanostructures with controlled morphologies have been synthesized by employing an ionic-liquid-assisted hydrothermal process. The basic strategies that were used in this work were: 1) A controllable phase transition from NH4-Dw to γ-AlOOH could be realized by increasing the reaction temperature and 2) the morphological evolution of NH4-Dw and γ-AlOOH nanostructures could be influenced by the concentration of the ionic liquid. Based on these experimental results, the main objective of this work was to clarify the effect models of the ionic liquids on the synthesis of NH4-Dw and γ-AlOOH nanostructures, which could be divided into cationic- or anionic-dominant effect models, as determined by the different surface structures of the targets. Specifically, under the cationic-dominant regime, the ionic liquids mainly showed dispersion effects for the NH4-Dw nanostructures, whereas the anionic-dominant model could induce the self-assembly of the γ-AlOOH particles to form hierarchical structures. Under the guidance of the proposed models, the effect of the ionic liquids would be optimized by an appropriate choice of cations or anions, as well as by considering the different effect models with the substrate surface. We expect that such effect models between ionic liquids and the target products will be helpful for understanding and designing rational ionic liquids that contain specific functional groups, thus open up new opportunities for the synthesis of inorganic nanomaterials with new morphologies and improved properties. In addition, these as-prepared NH4-Dw and γ-AlOOH nanostructures were converted into porous γ-Al2O3 nanostructures by thermal decomposition, whilst preserving the same morphology. By using HRTEM and nitrogen-adsorption analysis, the obtained γ-Al2O3 samples were found to have excellent porous properties and, hence, may have applications in catalysis and adsorption.

Role of self-assembly in construction of inorganic nanostructural materials

Understanding the evolution process and formation mechanism of nanoscale structures is crucial to controllable synthesis of inorganic nanomaterials with well-defined geometries and unique functionalities. In addition to the conventional Ostwald ripening process, oriented aggregation has been recently found to be prevalent in nanocrystal growth. In this new mechanism, primary small nanocrystals firstly spontaneously aggregate in the manner of oriented attachment, and then the large crystalline materials are formed via the process of interparticle recrystallization. Furthermore, controllable fabrication of the ordered nanocrystal solid materials that has shown specific collective properties will promote the application of inorganic nanocrystal in devices. Therefore, investigation of the mechanism of oriented aggregation is essential to controllable synthesis of nanocrystals and ordered nanocrystal solid materials. In this review, we summarize recent advances in the preparation of nanocrystal materials, which are mostly focused on our work about the role of self-assembly in construction of inorganic nanostructural materials.

Phytosynthesis of intracellular and extracellular gold nanoparticles by living peanut plant (Arachis hypogaeaL.)

Inorganic nanomaterials of different chemical compositions are conventionally synthesized under harsh environments such as extremes of temperature, pressure, and pH. Moreover, these methods are eco-unfriendly and cumbersome, yield bigger particles, and agglomerate because of not being capped by capping agents. In contrast, biological synthesis of inorganic nanomaterials occurs under ambient conditions, namely room temperature, atmospheric pressure, and physiological pH. These methods are reliable, eco-friendly, and cheap. In this paper, we report for the first time the extracellular and intracellular synthesis of gold nanoparticles (GNPs) using living peanut seedlings. The formed GNPs were highly stable in solution and inside the plant tissue. Transmission electron microscopy revealed that extracellular GNPs distributions were in the form of monodispersed nanoparticles. The nanoparticles ranged from 4 to 6nm in size. The intercellular nanoparticles were of oval shape and size ranged from 5 to 50nm. Both extracellular and intracellular nanoparticles were further characterized by standard techniques. The formed GNPs inside the plant tissue were estimated by inductively coupled plasma spectrometry. This opens up an exciting possibility of a plant-based nanoparticle synthesis strategy, wherein the nanoparticles may be entrapped in the biomass in the form of a film or produced in the solution, both of which have interesting applications.

Nanomaterials based on peptides

Owing to the assortment of functional groups, peptides are capable of self-assembly and formation of regularly patterned supramolecular complexes. Peptide-based nanomaterials offer promise for medicine, engineering, and bioimaging. The present review surveys the structure and characteristics of filaments formed by peptides of various secondary structures and their further assembly into 2D and 3D nanomaterials. Possible application areas of self-assembling peptide systems, including the synthesis of inorganic nanomaterials, are considered.

Role of self-assembly in construction of inorganic nanostructural materials

Understanding the evolution process and formation mechanism of nanoscale structures is crucial to controllable synthesis of inorganic nanomaterials with well-defined geometries and unique functionalities. In addition to the conventional Ostwald ripening process, oriented aggregation has been recently found to be prevalent in nanocrystal growth. In this new mechanism, primary small nanocrystals firstly spontaneously aggregate in the manner of oriented attachment, and then the large crystalline materials are formed via the process of interparticle recrystallization. Furthermore, controllable fabrication of the ordered nanocrystal solid materials that has shown specific collective properties will promote the application of inorganic nanocrystal in devices. Therefore, investigation of the mechanism of oriented aggregation is essential to controllable synthesis of nanocrystals and ordered nanocrystal solid materials. In this review, we summarize recent advances in the preparation of nanocrystal materials, which are mostly focused on our work about the role of self-assembly in construction of inorganic nanostructural materials.

Passing the limit of electrodeposition: ‘Gas template’ H2 nanobubbles for growing highly crystalline nanoporous ZnO

One of the most important challenges in the field of electrodeposition in aqueous media concerns the synthesis of inorganic nanomaterials with excellent control of the film microstructure, morphology and crystallinity. In this work, we present a ground-breaking method for tailoring highly crystalline nanoporous layers of ZnO upon transparent conductive oxide substrates which extends the limit of electrodeposition in aqueous media. Being surfactant and template-free, the design of a well-defined ZnO nanostructure has been achieved by means of an accurate control of the electro-assisted generation of hydrogen bubbles which play the role of a ‘gas template’ enabling the formation of dense to highly porous ZnO mesostructures depending on H2 evolution. Such layers were successfully introduced in solid-state dye-sensitized solar cells. In combination with an organic D-π-A dye (C220) and CuSCN as hole transporter material, we achieved 2.1% power conversion efficiency.

Self-Assembly of 2D Nanosheets into 3D Dendrites Based on the Organic Small Molecule ANPZ and Their Size-Dependent Thermal Properties

A surfactant-assisted self-assembly technique was developed to prepare three-dimensional (3D) dendritic micro-/nanostructures of 2,6-diamino-3,5-dinitropyrazine (ANPZ). The resulting micro-/nanostructures exhibited perfect fractal features. A series of experiments indicated that the formation of the dendritic ANPZ microstructures was dominated by the process nucleation and growth → aggregation → further growth, which is similar to the growth process of inorganic dendrites. The influence of various experimental parameters on the morphology of final product was also examined, and it was found that the size and morphology of the final product can be easily controlled by adjusting experimental parameters. In addition, the ANPZ micro-/nanostructures exhibited a seemingly morphology-dependent thermal effect that was actually size-dependent and has the potential for use in energy-demanding microscale systems. This wet chemical route, which has been widely used in the synthesis of inorganic nanomaterials, will provide useful information for the design and fabrication of organic small-molecule micro-/nanostructures with novel morphologies.

Process on Inorganic Nanomaterial Synthesis by Microwave-Hydrothermal Methods

The microwave-hydrothermal method is one of the methods preparing inorganic material. In this paper, the synthesis principle and application of microwave–hydrothermal technology in preparing nano-material were summarized. The application prospect of synthesizing inorganic material by microwave- hydrothermal method was prospected. The microwave- hydrothermal technology plays an important role in accelerating and optimizing the crystallization and nuclear of inorganic nano-material, which will provide a new way for inorganic material synthesis.

Ultrafast and Continuous Synthesis of Unaccommodating Inorganic Nanomaterials in Droplet- and Ionic Liquid-Assisted Microfluidic System

Despite many efforts on the synthesis of inorganic nanomaterials with uniform structure and narrow size distribution in a fast and continuous way, it is still a critical challenge in the chemistry research community due to the uncontrollable mass and heat transfer and the harsh experimental conditions of high temperature and pressure. Here we report a droplet- and ionic liquid-assisted microfluidic (DIM) synthesis method, which takes full advantage of both ionic liquids and droplet-assisted microreaction systems, for an ultrafast, mild, and continuous synthesis of various inorganic nanomaterials that takes only tens of minutes rather than days that are usually needed to synthesize. In particular, unaccommodating inorganic nanomaterials that are difficult to produce, such as nanoporous ZSM-5, γ-AlOOH, and β-FeOOH nanorods, were synthesized in only "20 minutes" of reaction time even with simple instrument. The DIM method delineated herein would offer a breakthrough synthetic approach for functional but unaccommodating inorganic nanomaterials in a continuous and mild manner.

Bio-inspired supramolecular self-assembly towards soft nanomaterials.

Supramolecular self-assembly has proven to be a reliable approach towards versatile nanomaterials based on multiple weak intermolecular forces. In this review, the development of bio-inspired supramolecular self-assembly into soft materials and their applications are summarized. Molecular systems used in bio-inspired "bottom-up self-assembly" involve small organic molecules, peptides or proteins, nucleic acids, and viruses. Self-assembled soft nanomaterials have been exploited in various applications such as inorganic nanomaterial synthesis, drug or gene delivery, tissue engineering, and so on.

Synthesis of Platinum Single-Twinned Right Bipyramid and {111}-Bipyramid through Targeted Control over Both Nucleation and Growth Using Specific Peptides

Shape-controlled synthesis requires rigorous kinetic control over both nucleation and growth. For platinum (Pt), to date it is still challenging to generate twinned seeds in nucleation in a controllable fashion. Here, we report that a specific Pt binding peptide BP7A is able to mediate and stabilize single-twinned seeds formation at the nucleation stage under mild conditions. Importantly, it targets the control over nucleation directly. Combining with control over growth, we further demonstrate the rational design and synthesis of single-twinned structures, right bipyramid and {111}-bipyramid, by incorporating targeted facet stabilization over {100} facet and {111} facet, respectively. To the best of our knowledge, this is the first report on the successful synthesis of single-twinned bipyramids for Pt nanocrystals (NCs) with high yields. The work here demonstrates the power of biomolecules in recognizing and mediating inorganic nanomaterials synthesis, guiding the formation of material structures that are otherwise unconventional, and hence presenting one step further toward predictable and programmable biomimetic synthesis.