Synthesis Of Inorganic Nanoparticles Research Articles

A novel approach to metal and metal oxide nanoparticle synthesis: the oil-in-water microemulsion reaction method

A novel and straightforward approach, based on oil-in-water (o/w) microemulsions, was developed for the synthesis of inorganic nanoparticles at ambient conditions. It implies the use of organometallic precursors dissolved in nanometre-scale oil droplets of o/w microemulsions. Addition of reducing or oxidizing/precipitating agents results in the formation of metallic or metal oxide nanoparticles, respectively. Nonionic o/w microemulsion systems were chosen, and several key compositions were selected for nanoparticle synthesis at 25 °C. High Resolution Electron Microscopy revealed that small nanoparticles of metals (Pt, Pd and Rh) and nanocrystalline metal oxide (cerium (IV) oxide with cubic type crystalline structure confirmed by XRD), of less than 7 nm can be obtained in mild conditions.

Synthesis of Organic Shell–Inorganic Core Hybrid Nanoparticles by Wet Process and Investigation of Their Advanced Functions

Abstract This account reviews the chemical synthesis of inorganic nanoparticles stabilized by an organic shell layer and the investigation of their specific characteristics. Consideration of design and construction of organic–inorganic hybrid nanoparticles by wet process is indispensable in order to exploit the unprecedented nature resulting from the fusion of both organic and inorganic traits. In a series of studies, two synthetic parameters were the center of focus: physical construction of the inorganic core and the chemical constituents introduced. External stimuli such as electric fields or solvent polarity can be utilized to transform the characteristics of nanoparticles when redox active or liquid crystalline molecules as an organic shell are attached to the surface of an inorganic nano-core. In another case, the catalytic activities of nanoparticles are controllable by modifying the crystal faces and the surface area of the inorganic cores in connection with shape and size. Novel nanomaterial has also been fabricated by choosing a metal coordination polymer as a core, leading to the first isolation of alkyl chain-stabilized metal coordination nano-polymers (MCNPs). The compounds are listed as Pt nano-cubes, size-selected Au nanoparticles, metal hexacyanoferrate MCNPs, and metal nanoparticles functionalized by biferrocene, anthraquinone, and triphenylene derivatives. Synthetic procedures and remarkable characteristics are demonstrated.

Influence of Cyclodextrin in the Synthesis of Magnetite

ABSTRACTCyclodextrin (CD) has been studied intensively due to its ability to form inclusion complexes with a variety of guest molecules in the solid state. A few studies have paid attention to the use of CD to facilitate the synthesis of inorganic nanoparticles. In this work the synthesis of magnetite (M) is made in the presence of CD. The particle size of the inorganic material is controlled by the presence of CD, in which spherical particles of few nanometers are grown. The synthesis of Fe3O4 (M) in the presence of α-cyclodextrin (α-CD) and β-cyclodextrin (βCD) is described. The formation of an M-CD complex is studied in both cases by Fourier transform infrared spectroscopy (FT-IR) in order to elucidate the chemical bonding of the complex. The morphology and size of the particles are determined by Field Emission Scanning Electron Microscopy (FESEM) and software. X-ray diffraction (XRD) is used to confirm the formation of magnetite.

A Facile One‐Pot Construction of Supramolecular Polymer Micelles from α‐Cyclodextrin and Poly(ε‐caprolactone)

A matter of control: A method has been developed for the construction of supramolecular polymer micelles (SMPMs) from α-cyclodextrin (α-CD) and poly(ε-caprolactone) (PCL) by controlling the intermolecular hydrogen bonds between CDs (see scheme). These micelles show great potential for use as drug carriers, templates for the synthesis of inorganic nanoparticles, and nanoreactors.

Nucleic acid and nucleotide-mediated synthesis of inorganic nanoparticles

Since the advent of practical methods for achieving DNA metallization, the use of nucleic acids as templates for the synthesis of inorganic nanoparticles (NPs) has become an active area of study. It is now widely recognized that nucleic acids have the ability to control the growth and morphology of inorganic NPs. These biopolymers are particularly appealing as templating agents as their ease of synthesis in conjunction with the possibility of screening nucleotide composition, sequence and length, provides the means to modulate the physico-chemical properties of the resulting NPs. Several synthetic procedures leading to NPs with interesting photophysical properties as well as studies aimed at rationalizing the mechanism of nucleic acid-templated NP synthesis are now being reported. This progress article will outline the current understanding of the nucleic acid-templated process and provides an up to date reference in this nascent field.

Polymer assisted hydroxyapatite microspheres suitable for biomedical application

Hollow Microspheres of hydroxyapatite-polymer composite can be used as carriers in drug delivery and fillers in tissue engineering. Based on the concept of soft chemistry, a battery of technique is available in the literature to synthesize hollow microspheres, however, an economically viable synthesis route, having good control over the microarchitect and easy to be scaled up, is yet to be developed. Polymer matrix mediated synthesis of inorganic nanoparticles is known to synthesize nanoparticles with controlled morphology and dimensions. It is termed as biomimetic synthesis. Integrating the biomimetic synthesis of nano-particles and spray drying techniques, a novel process of producing hydroxyapatite-polymer composite hollow microspheres is briefly discussed here.

Bio-template Synthesis of Nanoparticle by Cage-shaped Protein Supramolecule, Apoferritin

Bio-template methods for the synthesis of inorganic nano-particles are now attracting researchers’ interest in the bionanotechnology field. Using the protein cage, apoferritin, researchers have synthesized various kinds of nano-particles such as metal oxide nano-particles (Co, Ni, Cr nano-particles) and semiconductor nano-particles (CdSe, ZnSe) with a diameter of 7 nm. The synthesized nano-particles have high quality and a small diameter distribution. The mechanism of biomineralization in apoferritin has been studied and some knowledge has been accumulated. Biologically synthesized nanoparticles are now applicable to nanoelectronic devices and it is possible to produce floating gate memory with a monolayer of nanodots fabricated using apoferritins.

MICROGELS: Old Materials with New Applications

▪ Abstract This review describes the most recent progress in the use of polymer multiresponsive microgels as central components of advanced, functional colloidal materials. Significant areas of development include the use of microgels as microreactors for templated synthesis of inorganic nanoparticles with predetermined properties, as optically active materials including lenses and photonic crystals, and as primary units in site-specific and controlled drug delivery systems. In the last category, both synthetic and biopolymeric microgels are discussed.

金属イオン還元微生物を利用する貴金属ナノ粒子の合成

Although chemical and physical synthetic routes to inorganic solid nanoparticles have been extensively developed, another possibility is biological synthesis at room temperature under atmospheric pressure. The microbial synthesis of inorganic nanoparticles is potentially attractive as an environ-mentally friendly alternative to the conventional methods. This review focuses on the recent researches on metal-reducing microorganisms and their application to synthesis of noble metal nanoparticles. The mechanisms of microbial particle formation are discussed. Particular emphasis is placed on the microbial synthesis of gold nanoparticles by reducing soluble Au (III) to insoluble Au (0).

Recent achievements in the synthesis and application of inorganic nanoparticles as lubricant components

AbstractRecent advances made in the chemistry and technology of nano‐metric inorganic particles allow the synthesis of various metal oxides, chalcogenides, phosphates, and so on. Surface modification of nanoparticles in some cases allows the formation of stable dispersions in liquid hydrocarbons. The state of the art in the field of inorganic nanoparticle synthesis and their application in tribology are discussed in this paper. Special attention is paid to the synthesis of surface‐capped and bare molybdenum sulphide nanoparticles and to the testing thereof as friction‐modifying additives for liquid lubricants. Differences in the mechanism of action of MoSx nanoparticles and molecular molybdenum complexes (e.g., molybdenum dithiocarbamate) are discussed. Future trends in the use of inorganic nanoparticles as lubricant additives are suggested.

Analysis of a technical-grade w/o-microemulsion and its application for the precipitation of calcium carbonate nanoparticles

For a directed synthesis of inorganic nanoparticles in water-in-oil (w/o)-microemulsions the detailed investigation of the microemulsion system is of particular importance. This study illustrates that the phase behavior of the ternary as well as of the quaternary mixture (with reactants) has to be analyzed to identify microemulsion regions suitable for particle synthesis. Besides detailed phase prism investigations the microemulsion, consisting of water/reactant, cyclohexane and Marlipal O13/40, was further characterized. Dynamic light scattering studies have been conducted for determining the droplet size and viscosity measurements have been undertaken to clarify the internal structure. A time scale analysis of the involved processes during particle formation (e.g., droplet exchange, reaction, nucleation, growth and mixing) points out, that the utilization of w/o-microemulsions for precipitation reactions is an effective way to overcome mixing problems, which usually are present in bulk precipitation. This is demonstrated for the precipitation of CaCO 3 from two microemulsions containing dissolved Na 2CO 3 and CaCl 2, respectively. The influence of microemulsion composition, initial reactant concentration and holding time on the final particle size and shape was investigated. The resulting CaCO 3 nanoparticles have been characterized by means of a transmission electron microscope. Depending on the applied reaction conditions it is shown that different particle sizes and morphologies can be obtained.

Glutamate decarboxylase-derived IDDM autoantigens displayed on self-assembled protein nanoparticles

The recombinant ferritin heavy chain (FTN-H) formed self-assembled spherical nanoparticles with the size comparable to native one. We tried to express the GAD65 COOH-terminal fragments, i.e., 448–585 (GAD65 448–585), 487–585 (GAD65 487–585), and 512–585 (GAD65 512–585) amino acid fragments, using FTN-H as N-terminus fusion expression partner in Escherichia coli. All of recombinant fusion proteins (FTN-H::GAD65 448–585, FTN-H::GAD65 487–585, and FTN-H::GAD65 512–585) also formed spherical nanoparticles due probably to the self-assembly function of the fused ferritin heavy chain. The antigenic epitopes within GAD65 448–585, GAD65 487–585, and GAD65 512–585 against insulin-dependent diabetes mellitus (IDDM) marker (autoantibodies against GAD65) were localized at the surface of the spherical protein nanoparticles so that anti-GAD65 Ab could recognize them. Protein nanoparticles like FTN-H seem to provide distinct advantages over other inorganic nanoparticles (e.g., Au, Ag, CdSe, etc.) in that through the bacterial synthesis, the active capture probes can be located at the nanoparticle surface with constant orientation/conformation via covalent cross-linking without complex chemistry. Also it is possible for the protein nanoparticles to have uniform particle size, which is rarely achieved in the chemical synthesis of inorganic nanoparticles. Thus, the recombinant ferritin particles can be used as a three-dimensional (spherical) and nanometer-scale probe structure that is a key component in ultra-sensitive protein chip for detecting protein–small molecule interactions and protein–protein interactions.

Superparamagnetic Hybrid Nanocylinders

AbstractWell‐defined cylindrical polymer brushes with poly(acrylic acid) (PAA) cores and poly(n‐butyl acrylate) (PnBA) shells have been synthesized via a combination of anionic polymerization and atom transfer radical polymerization. These amphiphilic brushes are unimolecular cylindrical micelles and can be used as single‐molecular templates for the synthesis of inorganic nanoparticles, because the carboxylic acid groups (or carboxylate groups, after neutralization) in the polymer core can coordinate with various metal ions such as Fe3+ and Fe2+. Ultrafine magnetic nanoparticles were successfully synthesized within the core of these polymer brushes, as confirmed by various characterization techniques. Mössbauer spectroscopy and magnetization measurements indicate that the hybrid nanocylinders exhibit interesting superparamagnetic behavior.

Mechanochemical synthesis of nanoparticles

The results of recent investigation of the mechanochemical synthesis of inorganic nanoparticles are reviewed. It was demonstrated that, by selecting suitable chemical reaction paths, stoichiometry of starting materials and milling conditions, mechanochemical processing can be used to synthesise a wide range of nanocrystalline particles dispersed within a soluble salt matrix. Selective removal of the matrix phase by washing the resulting powder with appropriate solvents can yield nanoparticles of the desired phase. This technique has been shown to have advantages over other methods of producing nanoparticles in terms of low cost, small particle sizes, low agglomeration, narrow size distributions and uniformity of crystal structure and morphology.

Synthesis, Characterization, and Properties of Polyelectrolyte Block Copolymer Brushes Prepared by Atom Transfer Radical Polymerization and Their Use in the Synthesis of Metal Nanoparticles

Diblock copolymer polyelectrolyte brushes of either polystyrene (PS) or poly(methyl acrylate) (PMA) and poly(acrylic acid) (PAA) were synthesized using sequential monomer addition from a tethered 2-bromoisobutyrate initiator. Si/SiO2//PS-b-poly(tert-butyl acrylate) (P(t-BA)) and Si/SiO2//PMA-b-P(t-BA) were prepared by the “grafting from” method using atom transfer radical polymerization. The PAA block was prepared by hydrolysis of poly(tert-butyl acrylate) (P(t-BA)) and the polyelectrolyte was formed by subsequent treatment with either aqueous silver acetate or sodium tetrapalladate. Conversion of P(t-BA) to PAA and attachment of either silver or palladium ions to the PAA block was confirmed using ATR-FTIR spectroscopy, water contact angle measurements, and X-ray photoelectron spectroscopy. Solvent switching of the diblock copolymer brush using DMF and anisole was incomplete both before and after treatment with silver acetate, although the degree of switching was larger before treatment. The polyelectrolyte diblock copolymer brushes were used for the synthesis of inorganic nanoparticles by reduction of the treated PAA. These samples were characterized using AFM, XPS, and ATR−FTIR.

Metallodielectric Photonic Structures Based on Polyelectrolyte Multilayers

The processing of photonic structures using layer-by-layer assembly of polyelectrolytes and in-situ inorganic nanoparticle synthesis is reported. This approach facilitates the precise tuning of layer thicknesses and therefore optical response, and conformal large area coverage. Refractive index contrast of the polyelectrolyte multilayers (see Figure) is enhanced and manipulated by controlling silver nanoparticle concentration and distribution.