Preparation of fluorescent magnetic nanodiamonds and cellular imaging

Magnetic nanodiamonds were prepared via solid-state microwave arcing of a nanodiamond-ferrocene mixed powder in a focused microwave oven. High-resolution transmission electron microscope (HRTEM) images show that a magnetic nanodiamond is composed of iron nanoparticles encapsulated by graphene layers on the surface of nanodiamonds. Fluorescence property was introduced onto magnetic nanodiamonds by chemical modification of magnetic nanodiamonds via surface grafting of poly(acrylic acids) and fluorescein o-methacrylate. Fluorescent magnetic nanodiamonds are water soluble with a solubility of approximately 2.1 g/L. Cellular-imaging experiments show that fluorescent magnetic nanodiamonds could be ingested by HeLa cells readily in the absence of agonist (i.e., folate) moieties on the surface of nanodiamonds.     

Detonation nanodiamonds as catalysts of steam reforming of ethanol

Physicochemical properties and catalytic performance of detonation nanodiamonds were studied. Original samples of nanodiamonds and nanodiamonds modified by hydrogen, oxygen, and nitric acid with hydrogen peroxide and infrared-treated were investigated. The catalyst structure and morphology were examined by transmission electron microscopy and IR spectroscopy. All the investigated catalysts were active in the steam reforming of ethanol. The correlation of catalytic properties with composition and structure of the described systems is discussed. The specific surface area of nanodiamonds is changed insignificantly upon modification.     

Development of a rational technology for synthesis of high-quality detonation nanodiamonds

Concepts concerning the structure of detonation nanodiamonds were generalized on the basis of data reported in previous publications. The pH value of the nanodiamonds in an aqueous suspension was determined. The mechanism of the longest stage, washing of nanodiamonds with water to remove excess acidity, was considered. A novel method for substantially improving the quality of nanodiamonds and the stability of aqueous suspensions of nanodiamonds was suggested.     

Peculiarities of atomic hydrogen interactions with detonation nanodiamonds

Hydrogen treatment is a popular way of surface modification of nanodiamonds. Here, we used atomic hydrogen treatment of the functionalized surface to increase its hydrophobicity gently and maintain its overall composition. Corresponding mechanism was revealed via combination of theoretical and experimental methods.     

Are diamond nanoparticles cytotoxic?

Finely divided carbon particles, including charcoal, lampblack, and diamond particles, have been used for ornamental and official tattoos since ancient times. With the recent development in nanoscience and nanotechnology, carbon-based nanomaterials (e.g., fullerenes, nanotubes, nanodiamonds) attract a great deal of interest. Owing to their low chemical reactivity and unique physical properties, nanodiamonds could be useful in a variety of biological applications such as carriers for drugs, genes, or proteins; novel imaging techniques; coatings for implantable materials; and biosensors and biomedical nanorobots. Therefore, it is essential to ascertain the possible hazards of nanodiamonds to humans and other biological systems. We have, for the first time, assessed the cytotoxicity of nanodiamonds ranging in size from 2 to 10 nm. Assays of cell viability such as mitochondrial function (MTT) and luminescent ATP production showed that nanodiamonds were not toxic to a variety of cell types. Furthermore, nanodiamonds did not produce significant reactive oxygen species. Cells can grow on nanodiamond-coated substrates without morphological changes compared to controls. These results suggest that nanodiamonds could be ideal for many biological applications in a diverse range of cell types.     

Biohybrid fluorescent nanodiamonds as dual‐contrast markers for light and electron microscopies

Cathodoluminescence (CL) and correlative light‐electron microscopy (CLEM) are two useful analytical tools in diverse research areas. Recently, fluorescent nanodiamonds (FNDs) have emerged as promising imaging agents for both CL and CLEM owing to their exceptional photophysical and chemical properties. However, to realize their practical applications in the life sciences, surface modification and functionalization of the nanomaterials with bioactive molecules are critical and essential. Here we provide a comprehensive review on the methods of synthesizing biohybrid FNDs as well as recent advances of CL and CLEM imaging of cells with these carbon nanoparticles as dual‐contrast markers.     

毫秒脉冲激光合成超细纳米金刚石

通过热力学和动力学的基本理论, 分析了毫秒脉冲激光照射石墨悬浮液合成超细纳米金刚石的机理. 在毫秒脉冲激光与石墨颗粒相互作用形成的碳蒸气羽中, 通过碳蒸气凝聚形成了金刚石核. 与纳秒脉冲激光相比, 毫秒脉冲激光具有较低的功率密度和较长的脉宽, 为金刚石核的生长提供了较小的过冷度, 使得金刚石核的生长速率减小; 而较小的生长速率也为金刚石表面形成sp2杂化结构提供了机会, 它可以有效降低金刚石核的表面能, 促使金刚石核稳定, 但表面的sp2杂化也阻止了金刚石核的外延. 以上两个原因决定了毫秒激光辐照石墨颗粒过程中只能获得超细的纳米金刚石.     

The chemistry of the surface of modified detonation nanodiamonds of different types

The influence of standard chemical treatment used to extract interstellar nanodiamonds from meteorites on the chemical composition of the surface of synthetic nanodiamonds with substantially different properties was studied by thermal desorption mass spectrometry and IR spectroscopy. The chemistry of the surface of nanodiamonds after treatment was substantially different from that of initial particles. The suggestion was made that the chemical structure of the surface of diamond particles in the interstellar space could be reconstructed from the data on meteorite diamonds. Mass spectrometric studies also gave information about possible mechanisms of the release of noble gases from meteorite diamonds at various temperatures.     

Nanodiamonds in sugar rings: an experimental and theoretical investigation of cyclodextrin-nanodiamond inclusion complexes

We report on the noncovalent interactions of nanodiamond carboxylic acids derived from adamantane, diamantane, and triamantane with β- and γ-cyclodextrins. The water solubility of the nanodiamonds was increased by attaching an aromatic dicarboxylic acid via peptide coupling. Isothermal titration calorimetry experiments were performed to determine the thermodynamic parameters (K(a), ΔH, ΔG and ΔS) for the host-guest inclusion. The stoichiometry of the complexes is invariably 1:1. It was found that K(a), ΔG and ΔH of inclusion increase for larger nanodiamonds. ΔS is generally positive, in particular for the largest nanodiamonds. β-Cyclodextrin binds all nanodiamonds, γ-cyclodextrin clearly prefers the most bulky nanodiamonds. The interaction of 9-triamantane carboxylic acid shows one of the strongest complexation constants towards γ-cyclodextrin ever reported, K(a) = 5.0 × 10(5) M(-1). In order to gain some insight into the possible structural basis of these inclusion complexes we performed density functional calculations at the B97-D3/def2-TZVPP level of theory.     

Solubilization of carbon nanoparticles,nanotubes, nano-onions,and nanodiamonds through covalent functionalization with sucrose

Water solubilization of carbon nanoparticles (nanocarbons), single-walled nanotubes (SWCNTs), nano-onions (NOs) and nanodiamonds (NDs) has been achieved through their covalent functionalization by fluorination and subsequent derivatization with sucrose. The covalent bonding of sucrose to the surface of the fluorinated nanocarbons was attained by a one-step fluorine substitution reaction with sucrose-derived lithium monosucrate under sonication in DMF at room temperature. This chemical process provides a simple, inexpensive, and easily scalable method for hydrophilic chemical modification of SWCNT, NO, and ND surfaces to produce sucrose-functionalized nanocarbons that become soluble in water, DMF, ethanol, and other polar solvents. The sucrose-functionalized nanocarbon particles are expected to be biocompatible due to the abundance of hydroxyl groups available for hydrogen bonding and further chemical modification. Relevant examples have been given.     

Plasma Catalytic Synthesis of Ammonia Using Functionalized-Carbon Coatings in an Atmospheric-Pressure Non-equilibrium Discharge

We investigate the synthesis of ammonia in a non-equilibrium atmospheric-pressure plasma using functionalized-nanodiamond and diamond-like-carbon coatings on α-Al₂O₃ spheres as catalysts. Oxygenated nanodiamonds were found to increase the production yield of ammonia, while hydrogenated nanodiamonds decreased the yield. Neither type of nanodiamond affected the plasma properties significantly. Using diffuse-reflectance FT-IR and XPS, the role of different functional groups on the catalyst surface was investigated. Evidence is presented that the carbonyl group is associated with an efficient surface adsorption and desorption of hydrogen in ammonia synthesis on the surface of the nanodiamonds, and an increased production of ammonia. Conformal diamond-like-carbon coatings, deposited by plasma-enhanced chemical vapour deposition, led to a plasma with a higher electron density, and increased the production of ammonia.     

Modified method for synthesis of detonation nanodiamonds and their real elemental composition

Modified technique for synthesis of detonation nanodiamonds by exploding a charge of high explosives in a water shell is described. Reducing agents are introduced into water. Their use enables solution of a number of problems: the carbon content of nanodiamonds is raised from 90 to 96 wt %, the content of incombustible admixtures is dramatically diminished from 3 to 0.1 wt %, and the yield of detonation nanodiamonds becomes two times higher. A new method for determining the elemental composition is described and the oxidation of nanodiamonds under heating in the presence of atmospheric oxygen is analyzed.     

Preparation and properties of Miramistin–hyaluronic acid coatings on the nanodiamond surface

Hyaluronic acid is a promising coating for imparting biocompatibility to nanodiamond–antibiotic composites. It has been found that the adsorption of Miramistin on nanodiamonds with an initial negative zeta-potential increases the adsorption of hyaluronic acid, which remains lower than on positively charged nanodiamonds that are not affected by the pre-adsorption of Miramistin. The highest adsorption of hyaluronic acid is observed when Miramistin neutralizes the surface charge of nanoparticles.     

Magnetic resonance tracking of copper ion fixation on the surface of carboxylated nanodiamonds from viewpoint of changes in carbon-inherited paramagnetism

Detonation nanodiamonds with a particle size of 5 nm and a carboxylated surface are easily modified by doubly charged copper ions to form copper chelate complexes. The concentration of copper complexes in a dry powder of such nanodiamonds is well monitored by the method of electron paramagnetic resonance, both by the signal width of intrinsic paramagnetic centers in nanodiamonds and by the signal shape for the surface Cu²⁺ ions themselves, including the set of hyperfine splitting lines for the parallel component and the line with an unresolved hyperfine structure for the perpendicular component.     

Effect of Armoring Composition on the Yield of Nanodiamonds and Content of Impurities

Efficiency of using detonation nanodiamonds is strongly affected by the amount and elemental composition of impurities. The study considers the possibility of affecting the yield of detonation nanodiamonds and diamond-containing stock and the content and composition of incombustible impurities in the stock and diamonds by varying the composition of the water armor (shell) of the classical TNT–hexogen (50/50) charge. As compounds affecting the above parameters were used hydrazine, urotropin, ammonia, urea, Trilon B (disodium salt of ethylene diamine tetraacetic acid), aminotetrazole, and boric acid. It was found that using urotropin was the optimal as regards a whole set of parameters. In this case, the maximum yield of detonation nanodiamonds (6.9%) and diamond-containing stock (13.4%) was obtained. A close yield of the diamond-containing stock and detonation nanodiamonds was provided by using hydrazine and urea in the armor. Use of boric acid in the armor can substantially diminish the variety of impurity elements in the diamond-containing stock and detonation nanodiamonds at an acceptable yield of the diamond-containing stock (11.1%) and detonation nanodiamonds (6.13%). Use of pure water as the armor is inefficient.     

Ion chromatographic investigation of the ion-exchange properties of microdisperse sintered nanodiamonds

The possibility of using sintered diamonds as a stationary phase in ion chromatography has been evaluated. Bare sintered synthetic nanodiamonds demonstrated the properties of a weak cation-exchanger. The observed ion-exchange selectivity is similar to carboxylic type cation-exchangers. The regularities of retention of alkali, alkaline-earth and transition metal ions on a column packed with sintered nanodiamonds in dilute nitric acid were studied and the occurrence of chelating properties was noted. For the first time chromatographic separations of model mixtures of cations on diamonds have been obtained.     

A nickel-substituted form of nanodiamonds and its catalytic activity in decomposition of hydrogen peroxide

Adsorption of nickel (II) ions with nanodiamonds obtained by the detonation synthesis was studied. A nickel-substituted form of nanodiamonds was obtained. The catalytic activity exhibited by nickel ions (II) in the form of the surface complexes with nanodiamond functional groups in decomposition of hydrogen peroxide was determined.     

Preparation and characterization of Zonyl-coated nanodiamonds with antifouling properties

The paper reports on covalent linking of a modified amphiphilic polymer, the alkynyl-terminated Zonyl, to azide-terminated nanodiamonds by click chemistry. An analysis of the hybrid particle stability is presented based on size and zeta potential measurements. The antifouling character of the grafted nanodiamonds was investigated using bovine serum albumin as a model protein. The protein adsorption was quantified using a Bradford assay and found to be reduced by 30% in the presence of the Zonyl layer.     

Surface modification of detonation nanodiamonds by the perfluorobutyl radical

The method was developed for surface defunctionalization of detonation nanodiamonds by substitution of a perfluorinated organic radical for hydroxyl and carboxyl groups. Size-mass distributions of modified particles of detonation nanodiamonds in water and toluene were studied     

Interaction of shungite carbon nanoparticles with blood protein and cell components

We have analyzed and compared the effects of aqueous dispersion of shungite carbon nanoparticles, fullerene C₆₀, and nanodiamonds on structure, dynamics, and thermodynamic and redox properties of blood proteins (serum albumin and hemoglobin), proteins of erythrocyte ghost membranes as well as on erythrocyte integrity and aggregation.. All the nanomaterials dispersions have induced similar effects; however, nanodiamonds have not influences the redox properties. Basing on the results, the experimental and theoretical approaches presented can be employed to estimate the effects of biological structures contact with the nanoparticles on the bioreactivity.