Journal of Nanostructure in Chemistry

Core–shell magnetosensitive nanocomposites (NC) based on single-domain magnetite (Fe3O4, core), with a shell consisting of hydroxyapatite (HA) and cytotoxic drug doxorubicin (DOX) layers have been synthesized. The processes of DOX adsorption on Fe3O4/HA surface from physiologic solution have been studied. DOX release into saline was found to decrease with growing of its quantity on NC surface. It has been determined that cytotoxic influence and antiproliferative activity of Fe3O4/HA/DOX NC with respect to Saccharomyces cerevisiae cells are characteristic for interaction of these cells with a free form of doxorubicin. Magnetic liquids containing Fe3O4/HA/DOX NC stabilized by sodium oleate and polyethylene glycol were prepared and investigated. It is shown that using the ensemble of Fe3O4 carriers as a superparamagnetic probe, the Langevin’s paramagnetism theory, and the values of density of nanocomposite constituents, one can evaluate the size parameters of their shell, which has been corroborated by independent measurements of specific surface area of nanostructures and kinetic stability of the corresponding magnetic liquids. The obtained results may be useful for development and optimization of novel forms of magnetocarried medical remedies of targeted delivery and adsorbents based on nanocomposites of superparamagnetic core–shell type with multilevel nanoarchitecture, as well as for determination and control of the size parameters of its components.

The present work is designed to investigate the impact of shock waves on Zinc Ferrite nanoparticles (ZnFe2O4) NPs. The test material was prepared by precipitation method and shock wave recovery experiment is done by tabletop pressure driven shock tube. The shock wave induced changes in structural, morphological and magnetic properties are noticed by various analytical techniques such as powder X-ray Diffractometer (PXRD), fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) and the obtained PXRD results shows no significant structural changes. Switchable paramagnetic to superparamagnetic behaviour is observed during the shock wave loaded conditions. The mechanism of shock wave induced magnetic phase transition is discussed.

Graphene-based inorganic layered materials have developed as a versatile, new class of nanomaterials and drawn huge scientific interest, owing to its thickness-dependent physical properties, exfoliated two-dimensional crystals in various technological and industrial applications. This work is the first demonstration of the fabrication of low dimensional bismuth selenide (Bi2Se3) NPs functionalized reduced graphene oxide (rGO) on the platinum electrode (Pt-E) for the ultra-sensitive and simultaneous detection of acetaminophen (ACT) and L-DOPA (LD) in the presence of ascorbic acid (AA) in various biological samples and pharmaceuticals. The constructed electrode accelerates the electron transfer reactions of LD and ACT without interfering with the electron transfer reactions of AA, which was an electroactive coexisting chemical. At pH 6.0 in 0.1 M phosphate buffer solution, Bi2Se3 NPs/rGO/Pt-E showed a sixfold and fivefold increase in cyclic voltammetry for LD and ACT signals, respectively, when compared to bare Pt-E. Under the optimal conditions, differential pulse voltammetry (DPV) demonstrated that the anodic peak currents were linearly dependent on the concentrations of LD (0.006–0.25 mM) and ACT (0.0045–0.14 mM) at anodic peak potentials of + 0.25 and + 0.52 V, respectively. With a signal to noise (S/N) ratio of 3, acceptable detection limits of 0.23 and 0.17 M were achieved for both LD and ACT, with strong intra- and inter-electrode repeatability. Overall, the fabricated nanosensor offered numerous advantages including ease to fabricate, ultra-sensitivity, good stability, and reproducibility towards the detection of LD and ACT in various bioloical samples and pharmaceuticals. The amounts of LD and ACT were also identified in commercial pharmaceuticals and synthetic urine samples to validate the applicability of the modified electrode.

In the present paper, we have studied a new approach to the description ofcorrelation between the optical and structural properties of ZnO thin films withdoping levels of Al, Co, and In. The doped zinc oxide thin films were depositedusing ultrasonic spray technique on a glass substrate at 350°C. Thecorrelation between structural and optical properties with doping level suggeststhat the crystallite size of the films is predominantly estimated by the bandgapenergy and the concentration of Al, Co, and In. Also, the gap energy of dopedfilms was estimated by the crystallite size and doping level. The measurement inthe crystallite size and optical gap energy of doped films with correlation isequal to the experimental data. The minimum error value was estimated in dopedZnO thin films with indium and cobalt. Thus, results indicate that such Co-dopedZnO thin films are chemically purer and have many fewer defects and lessdisorder, owing to an almost complete chemical decomposition.

Visible-light-activated Cr₂O₃/SnO₂ nanocomposite photocatalyst was prepared by coprecipitation method and characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N₂ adsorption-desorption measurement, and UV–vis diffuse reflectance spectroscopy. The results show that phase composition, crystallite size, Brunauer-Emmett-Teller surface area, and optical absorption of samples varied significantly with the heat treatment temperatures. The Cr₂O₃/SnO₂ photocatalyst (the molar ratio Cr to Sn is 1:2) calcined at 400°C for 2 h exhibited maximum photocatalytic activity because it has a smaller particle size of 10.05 nm and a higher surface area of 38.75 m²/g. Under visible-light (λ > 400 nm) irradiation, the degradation rate of Rhodamine B reached 98.0% in 60 min, which is about 3.5 times higher than that of the standard P25 photocatalyst.

Azaperone is a very important phenylbutanone-based neurotransmitter used in the treatment of some animal (veterinary) clinics. This compound has various nerve and tendon stabilizing agents on livestock and animals. Muscular injection of azaperone is used to reduce stress in livestock and reduce their acting. In the present work, Fe₃O₄@SiO₂-NH₂/CS₂ nanocomposite was synthesized and thoroughly characterized using FE-SEM, FT-IR, and XRD technique. The glassy carbon electrode was then modified with nanocomposite to fabricate a sensor named GCE/Fe₃O₄@SiO₂-NH₂/CS₂. The application of modified electrode was tested for analysis of azaperone in ostrich meat and rat plasma. The electrochemical behavior of azaperone was tested using differential pulse and cyclic voltammetry. In Briton–Robinson buffer solution (pH = 6), azaperone had an oxidation peak at 0.82 V. Cyclic voltammetry studies indicated that the azaprone oxidation process on the modified electrode is irreversible. Experimental variables, including pH and accumulation time were optimized by monitoring the cyclic voltammetry responses toward azaperone peak current. Measurement of azaperone by differential pulse voltammetry technique showed linearity of anodic peak current vs. azaperone concentration in a range of 0.01–100.0 μM with detection and quantification limits of 3 nM and 10 nM, respectively. Also, the effect of disturbance of some species as possible interferers on the electrochemical response of azaperone was checked out. Finally, the capability of the fabricated sensor for azaperone measurement was successfully tested in ostrich meat and rat plasma as real samples.

Graphical abstract

In the present work, adsorption and dif fusion of oxygen (O) atom on uranium dinitride (UN2) is studied to map out the preferential UN2(100) surface site. The first principle method based on density functional theory (DFT) within the generalized gradient approximation PBE and the covariant version energy functional PBE + U correction were used. The supercell approach and a coverage dependence of the adsorption structures and energetic were studied in detail for several monolayers’ (ML) range. Potential energy surfaces (PES) corresponding to the interaction between O atom and UN2(100) on surface and subsurface for several sites and layers (Top U and Top N slabs) were calculated and favorable sites were identified with their maxima energy stable positions, which were then analyzed. For all positions, the PES show the same system behavior, when the O atom is sufficiently far from the UN2 surface, and the energy of the system tends to the sum of free UN2 slab and free oxygen atom energies. In return, when the distances decrease, strong interactions appear with presence of important potential wells. Calculation results showed that favored on-surface site for O atom adsorption were found to be near the bridge one for the UN (Top U slab) corresponding to five layers, uranium terminated and top one for (Top N slab) corresponding to six layers nitrogen terminated, the maximum system energy is situated at a position of about 1.2 and 1.5 Å from the surface for the two layers types calculations respectively. For subsurface results, only Top N presents a favorable incorporation site at the hollow position and the penetration of O atom is about −0.5 Å from the surface. DFT + U study confirms all the results obtained by DFT calculations; that is, the maxima site positions for oxygen atom and the adhesion energy values per atom are of the same order of magnitudes. The adsorption energy per oxygen atom and the mean distance from the top surface gradually decrease with the coverage of O atoms for both on-surface cases, Top U and Top N slabs, with oxygen occupying the favorable site. For the Top N slab hollow site, the incorporation of oxygen through the surface becomes effective from a coverage of 3/8 ML with an encrustation of about −0.3 Å.

An Ag–Cu (AC) bimetallic alloy nanoparticles in various proportions were fabricated by facile electrochemical process is presented in this work. Apart from the electrochemical method of synthesis, the surface morphology, crystal structure and texture as well as the optical properties of the nano alloy have been investigated. The surface morphology and the particle size of the Ag–Cu deposits were deliberated by scanning electron microscopic studies. The preferred orientation and average particle size of the AC NTs were obtained by X-ray diffraction analysis. The well-dispersed AC nano alloy (NA) exhibited ultrafine size and high crystallinity corresponding to face centered cubic Ag and Cu. Ultraviolet–visible spectroscopy was performed to study the optical properties of the nano alloy and the results showed that the nano alloys have wide band gap energies 3.18, 3.57 and 3.03 eV for AgCu, AgCu2 and AgCu3 NAs, respectively. The studies on size, morphology and composition of the nanoparticles were performed by means of transmission electron microscopy, and energy dispersive X-ray Analysis.