Modified Nanodiamonds Research Articles

Терапевтический эффект наноалмазов взрывного синтеза при кобальтиндуцированном дерматите

The aim of the research. To evaluate the therapeutic eff ect of modifi ed nanodiamonds (MND) of explosive synthesis for treatment of allergic contact dermatitis induced by cobalt ions. Material and methods. Th e study was performed on guinea pigs. Th e animals were divided into 3 groups (6 animals in each group). Allergic contact dermatitis was initiated using 2% aqueous solution of cobalt nitrate applied to the animals’ skin for 14 days according to the common procedure. For allergic contact dermatitis treatment, glycerol and MND suspension with the nanoparticle concentration of 5g · l-1 prepared in glycerol were used. MND with high colloidal stability in water suspensions and the average nanoparticle cluster size of d50 = 50nm was used in the work. Th e animals of group I were controls: aft er allergic contact dermatitis development, their skin was not treated by any means for 7 days. Th e animals in groups II and III were experimental: aft er allergic contact dermatitis initiation, their skin was treated for 7 days using glycerol and MND suspension, respectively. Upon experiment completion, biopsy of skin sample was performed on all animals for histological and spectral examination. The content of cobalt in skin samples was determined through atomic adsorption spectroscopy. Results. The results of histological and morphometric analysis indicate that, in the case with dermatitis modelled in guinea pigs using cobalt ions, treatment of the animals’ skin with MND suspension reduces allergic inflammation intensity. Th e therapeutic effect of MND is caused by adsorption of cobalt ions onto nanoparticles and their subsequent elimination from the skin, which complies with the atomic adsorption spectroscopy data. Conclusion. Th e prospects of MND as a new therapeutic agent for binding and elimination of chemical allergens (particularly, cobalt ions inducing the allergic contact dermatitis development) are discussed.

Reusable System for Phenol Detection in an Aqueous Medium Based on Nanodiamonds and Extracellular Oxidase from Basidiomycete Neonothopanus nambi.

A reusable system for phenol determination in an aqueous medium was obtained by adsorption of extracellular oxidase from fungus Neonothopanus nambi onto modified nanodiamonds (MND) synthesized by detonation. It was found that the enzyme strongly binds to MND and exhibits catalytic activity in the reaction of co-oxidation of phenol with 4-aminoantipyrine without the addition of hydrogen peroxide. In the presence of the MND-oxidase complex, a significantly (by an order of magnitude) higher yield of the reaction product is recorded as compared to the yield in the presence of a free enzyme; the mechanism of the revealed effect is discussed. Model experiments have demonstrated the multiple use of the MND-oxidase complex for testing phenol in aqueous samples. The immobilized enzyme exhibits functional activity during long-term (2 months) storage of the MND-oxidase complex at 4°C. The data obtained create the prerequisites for using the created system in environmental monitoring of water pollution with phenol.

Fabrication of a composite based on aluminum oxide nanofibers and nanodiamonds to construct phenol detection systems

A composite based on aluminum oxide nanofibers (AONF) and modified nanodiamonds (MND) synthesized by explosion technique was made by mixing aqueous suspensions of components at a 5:1 weight ratio and incubating the mixture for 15 minutes at 32 C. It is assumed that the formation of a composite is provided by the difference in the zeta-potentials of the components - negative for MND and positive for AONF. Vacuum filtration of the mixture through a fluoroplastic filter (pore diameter of 0.6 m) formed discs with a diameter of 40 mm with subsequent heat treatment at 300 C to impart structural stability to the composite. Using scanning electron microscopy (SEM), it was revealed that the resulting composite has a network structure in which the MND particles are distributed over the AONF surface. It was established that MND incorporated into the composite catalyze the azo coupling reaction (phenol - 4-aminoantipyrine - H2O2) with the formation of a colored product (quinoneimine). The applicability of the composite for the multiple detection of phenol in aqueous samples is demonstrated.

A Supramolecular Indicator System for Detecting Urea Based on the Cellulose-Nanodiamond Composite Material and Urease

A supramolecular indicator system (cellulose-nanodiamonds-urease) for reusable biochemical detection of urea has been fabricated using sequential immobilization of the components. Modified nanodiamonds (MNDs) were covalently immobilized onto DEAE cellulose granules via the nucleophilic addition reaction. At DEAE cellulose: MND ratio of 4:1 (w/w), up to 110 µg of nanoparticles bound onto 1 mg of the polymer during the addition reaction. Urease was immobilized by covalent conjugation onto the polymer-MND composite with the benzoquinone-activated surface. In comparative experiments, the enzyme was immobilized onto initial polymer granules via nonspecific adsorption and covalent conjugation.

EPR Spectrometric Estimation of the Distribution of Intravenously Injected Nanodiamonds in Mice

The distribution in mice of intravenously injected modified nanodiamonds (MNDs) obtained by detonation synthesis was studied using electron paramagnetic resonance (EPR) spectrometry. It has been shown that 2.5 h after MND injection into the tail vein of mice, the nanoparticles accumulate mainly in the lungs and liver of animals; much smaller amounts of nanoparticles were found in the kidneys and heart. The presence of MNDs in the samples of blood, spleen, brain, and thigh muscles of mice was not detected within the sensitivity of the method used.

Nanodiamonds as an effective adsorbent for immobilization of extracellular peroxidases from luminous fungus Neonothopanus nambi to construct a phenol detection system

Modified nanodiamonds (MNDs) produced by detonation synthesis can be used as an effective adsorbent to immobilize extracellular peroxidases of the luminous basidiomycete Neonothopanus nambi. The enzymes are firmly immobilized on MND particles and exhibit catalytic activity. The indicator system (the MND–enzyme complex) reused many times retains its ability to catalyze reaction of co-oxidation of phenol and 4-aminoantipirine in the presence of hydrogen peroxide and remains functionally active during long-term storage (for 1 month or longer) in aqueous suspensions at 4 °C. MNDs and enzymes of higher fungi can be effectively used to construct new reusable indicator systems for analytical applications such as monitoring contamination of aquatic environments by phenolic compounds.

Creation of Bifunctional Indicating Complex Based on Nanodiamonds and Extracellular Oxidases of Luminous Fungus Neonothopanus nambi.

A bifunctional indicating complex was created by immobilization of extracellular oxidases (glucose oxidase and peroxidases) of luminous fungus Neonothopanus nambi onto modified nanodiamonds (MNDs) synthesized by detonation. It was found that the enzymes firmly adsorb onto MND particles and exhibit their catalytic activity. Model in vitro experiments showed that the created MND-enzymes complex is suitable for repeated use for analyte (glucose and phenol) testing and retains its activity after storage at 4°C in deionized water for 1 month. The data obtained offer the prospects for developing a new class of reusable multifunctional indicating and diagnostic test systems on the basis of MNDs and higher fungal enzymes for medical and ecological analytics.

Detection of nanodiamonds in biological samples by EPR spectrometry.

In model experiments in vitro, the applicability of the EPR spectrometry method for the detection of modified nanodiamonds (MNDs) in blood and homogenates of mouse organs has been established. A characteristic signal (g = 2.003, ΔH ≈ 10 G) is observed in the samples of biomaterials containing MNDs, the intensity of which increases linearly with the concentration of nanoparticles in the range of 1.6-200 μg MNDs per 1 mL of the sample. The EPR method in biomaterials reveals the presence of intrinsic paramagnetic centers, signals from which are superimposed on the signal from the MNDs. However, the intensity of these signals is small, which makes it possible to register the MNDs using EPR spectrometry with the necessary accuracy. The data obtained open up the prospects of using the EPR method for studies of the interorgan distribution, accumulation, and elimination of MNDs during their intravenous injection into experimental animals.

On the applicability of nanodiamonds produced by detonation synthesis for phenol testing in aqueous media

It was found that the catalytic effect of modified nanodiamonds (MND) in the H2O2–4-aminoantipyrine–phenol oxidative azo coupling reaction is due to microimpurities of iron and copper ions on the surface of nanoparticles. The efficiency of MND as a catalyst is determined by the amount of surface impurities of these ions and can be doubled by their additional adsorption on nanoparticles. Using MND for phenol indication ensures a linear yield of the colored product of the azo coupling reaction over an analyte concentration range of 0.05–10 μg/mL. The possibility of reusing MND for phenol testing in aqueous samples was demonstrated.

Adsorption of viral particles from the blood plasma of patients with viral hepatitis on nanodiamonds.

Adsorption of viral particles from the blood plasma of patients with viral hepatitis B and C on modified nanodiamonds (MNDs) was shown in the in vitro experiments. PCR method showed the treatment of plasma with MNDs leads to a decrease in the viral load by 2-3 orders of magnitude or more in both cases studied. These results make it possible to predict the applicability of MNDs for the development of new technologies of hemodialysis and plasmapheresis for binding and removal of viral particles from the blood of infected patients.

The Effects of Nanodiamonds at the Action of Colored Metal Ions on the Skin of Guinea Pigs

The protective effect of modified nanodiamonds (MND) under the action of cobalt and nickel ions on the skin of Guinea pigs was shown. At the action of chromium ions on the skin of animals, the protective effect of MND was not found. The differences are related to different adsorption properties of MND to the investigated colored metal ions. It is shown in vitro that MND can adsorb ions of cobalt and nickel and don’t bind ions of chromium from aqueous medium. The perspectives using of MND as a new drug for the prevention allergic dermatitis caused by action of bivalent ions of metals are discussed.

Designing a reusable system based on nanodiamonds for biochemical determination of urea.

A reusable system including urease covalently bound to the surface of modified nanodiamonds (MNDs) has been developed for the multiple determination of urea. The immobilized enzyme exhibits functional activity and catalyzes the hydrolysis of urea to yield ammonia. The presence of ammonia is confirmed by the formation of a colored product after the addition of chemical reagents. It was shown that the MNDs-urease complex can function in a wide range of temperatures and pH as well as in deionized water. The complex provides a linear yield of the product at low analyte concentrations and allows the multiple determination of urea in vitro.

Nano Titania Modified Nanodiamonds as Stable Electrocatalyst Supports for Direct Methanol Fuel Cells

Nano titania modified nanodiamond (TiO2/ND) was prepared by a microwave hydrolysis method, and then platinum nanoparticles (NPs) were deposited on the TiO2/ND support using a microwave-assisted polyol method. TiO2/ND supported Pt (Pt/TiO2/ND) electrocatalyst was characterized by X-ray diffraction and transmission electron microscopy. The electrocatalytic activity for methanol oxidation reaction (MOR) was investigated by cyclic voltammetry and chronoamperometry. It was found that anatase TiO2 NPs with the sizes of 4∼8 nm were distributed on the ND surface uniformly, and Pt NPs highly dispersed on the TiO2/ND support. The electrochemical results showed that the Pt/TiO2/ND catalyst possessed higher electrocatalytic activity for MOR compared with the Pt/ND in acid medium. A high stability of Pt/TiO2/ND catalyst was ascribed to an anchoring effect of the TiO2 layer and a high stability of the TiO2/ND support in acid solution.

Catalytic Activity of Nanodiamonds in Azocoupling Reaction

The catalytic efficiency of modified nanodiamonds (MND) in reactions of interaction between organic compounds was demonstrated on the example of azocoupling reaction (hydrogen peroxide-4-aminoantipyrine-phenol). It was found that catalytic action of MND was caused by redox active metal ions of Fe and Cu located on the MND surface. The neutralization of the ions significantly decreased catalytic properties of MND.

The effect of the size factor of nanodiamonds in suspensions on optical power limiting and nonlinear laser light scattering

The results of experimental studies of optical power limiting (OPL) and nonlinear light scattering (NLS) at a wavelength of 532 nm in suspensions of detonation-synthesis modified nanodiamonds (MNDs) with different grain-size compositions are described. It is found that, at the same nanoparticle concentration, OPL and NLS are more efficient in suspensions with large MNDs. It is shown that MND suspensions can exhibit a stable long-term operation as OPL in a field of laser pulses with a power density of 0.2 GW/cm2 at a repetition frequency of 1 Hz.

Nanodiamond-Based Tests Systems for Biochemical Determination of Glucose and Cholesterol

Model test-systems for biochemical determination of glucose and cholesterol are designed by covalent coupling of enzymes to the surface of modified nanodiamonds (MND). In both cases after immobilization on MND the enzymes exhibit activity and catalyze the formation of a colored product in the chain of successive enzymatic reactions of oxidative azocoupling (Н2О2—4-aminoantipyrine—phenol). Produced MND-enzymes complexes: function in DI water and various buffers, over a wide range of temperature and pH, provide for the linear product yield over a broad concentration range of analyzed substances, make possible to test cholesterol and glucose in vitro many times, exhibit functional activity after long storage at + 4°C.

Hematological Parameters and the State of Liver Cells of Rats After Oral Administration of Aflatoxin B1 Alone and Together with Nanodiamonds

Hematological parameters and the state of liver cells of rats were examined in vivo after the animals received aflatoxin B1 (AfB1) alone and together with modified nanodiamonds (MND) synthesized by detonation. The rats that had received the MND hydrosol had elevated leukocyte levels, mainly due to higher granulocyte counts and somewhat increased monocyte counts compared to control rats. Hematological parameters of the rats that had received AfB1 alone differed from those of the control rats in another way: total white blood cell counts were significantly lower due to the decreased lymphocyte counts. In rats that had consumed AfB1 with the MND hydrosol, changes in hematological parameters were less pronounced than in rats that had consumed either AfB1 or MND. Electron microscopy showed that hepatocytes of the rats that had received the MND hydrosol or AfB1 with the MND hydrosol contained elevated levels of lipid inclusions and lysosomes. Hyperplasia of the smooth endoplasmic reticulum (EPR) was revealed in liver specimens of the rats that had received AfB1. Results of the study suggest the conclusion about mutual mitigation of the effects of nanoparticles and the mycotoxin on rats blood and liver cells after AfB1 has adsorbed on MND.