Super-paramagnetic nanostructured CuZnMg mixed spinel ferrite for bone tissue regeneration.

Spinel ferrite-based nanoparticles are being widely applied in bone tissue regeneration because of their outstanding properties such as their capability to be applied in hyperthermia-based bone cancer therapy. In the present study, Cu0.3Zn0.2Mg0.5Fe2O4 nanoparticles are synthesized through thermal-treatment method followed by calcination at 650 °C. The calcined nanoparticles are characterized through X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS) and elemental mapping, Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Then from the nanoparticles, a disk is fabricated and sintered at 800 °C to assess Cu0.3Zn0.2Mg0.5Fe2O4 basic requirements of a bone substitute like apatite-formation ability, degradation, mechanical properties, and cell compatibility and so compressive strength, apatite forming ability up to 21 days in simulated body fluid (SBF), in vitro degradation in two different buffers, antibacterial activity, cell compatibility, and attachment are assessed in vitro. The results show that the magnetization saturation (Ms) is increased from 52 to 60 emu/g when the nanoparticles are sintered at 800 °C. Immersion the disk into SBF is synchronized with deposition of spherical CaP particles on the surface of disk and the XRD after soaking period proves that the depositions are hydroxyapatite. The degradability of disk is assessed into phosphate buffer saline (PBS) and citric acid buffer (CAB) up to 21 days. A gram-positive and a gram-negative bacteria are used to assess the disk's antibacterial activity and the disk exhibits acceptable activity against both of them. The cell compatibility and attachment of disk in the exposure of MG63 cell line are assessed up to 7 days and the results prove high cell compatibility of the disk.

Taguchi method optimization for synthesis of Fe3O4 @chitosan/Tragacanth Gum nanocomposite as a drug delivery system.

Polysaccharides as natural hydrogels provide a promising strategy to prepare stimuli responsive drug carriers in pharmaceutical industries. In this work, Fe3O4 magnetic nanoparticles (MNPs) functionalized with (3-amino propyl) triethoxy silane (APTES) and coated by Chitosan (CS) and Tragacanth Gum (TG) to encapsulate curcumin. The synthesized nanocomposite was characterized using FT-IR, FE-SEM, EDX and XRD analysis. Taguchi Method (L9) with 3 levels and 4 variables was used to optimize the effect of concentration of Fe3O4@APTES, TG: CS ratio, nanocomposite weight, and curcumin weight on the drug loading. The release behaviour of curcumin was further studied in two different pH 7.4 and 3.4 and at temperatures 37 °C and 40 °C. The nanocomposite showed a higher swelling ratio at pH 3.4 and temperature 40 °C with good pH and thermosensitive in vitro drug release profiles. The results indicate that the nanocomposite has a good potential for delivery of chemotherapeutic drugs.

Structural and impedance spectroscopy characteristics of BaCO3/BaSnO3/SnO2 nanocomposite: observation of a non-monotonic relaxation behavior.

A BaCO3/BaSnO3/SnO2 nanocomposite has been prepared using a co-precipitation method without adding any additives. The prepared sample was characterized by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. Detailed studies on the dielectric and electrical behavior (dielectric constant, complex impedance Z*, ac conductivity, and relaxation mechanisms) of the nanocomposite have been performed using the nondestructive complex impedance spectroscopy technique within the temperature range 150-400 K. The dielectric constant of the sample as a function of temperature showed the typical characteristics of a relaxor. The maximum dielectric constant value was observed to depend on frequency. The non-monotonic relaxation behavior of the prepared nanocomposite was evidenced from the spectra of loss tan, tan(δ). The relaxation kinetics was modeled using a non-Arrhenius model.

Dielectrical Properties of CeO2 Nanoparticles at Different Temperatures.

A template-free precipitation method was used as a simple and low cost method for preparation of CeO2 nanoparticles. The structure and morphology of the prepared nanoparticle samples were studied in detail using X-ray diffraction, Raman spectroscopy and Scanning Electron Microscopy (SEM) measurements. The whole powder pattern modelling (WPPM) method was applied on XRD data to accurately measure the crystalline domain size and their size distribution. The average crystalline domain diameter was found to be 5.2 nm, with a very narrow size distribution. UV-visible absorbance spectrum was used to calculate the optical energy band gap of the prepared CeO2 nanoparticles. The FT-IR spectrum of prepared CeO2 nanoparticles showed absorption bands at 400 cm(-1) to 450 cm(-1) regime, which correspond to CeO2 stretching vibration. The dielectric constant (εr) and dielectric loss (tan δ) values of sintered CeO2 compact consolidated from prepared nanoparticles were measured at different temperatures in the range from 298 K (room temperature) to 623 K, and at different frequencies from 1 kHz to 1 MHz.

The effect of laser repetition rate on the LASiS synthesis of biocompatible silver nanoparticles in aqueous starch solution.

Laser ablation-based nanoparticle synthesis in solution is rapidly becoming popular, particularly for potential biomedical and life science applications. This method promises one pot synthesis and concomitant bio-functionalization, is devoid of toxic chemicals, does not require complicated apparatus, can be combined with natural stabilizers, is directly biocompatible, and has high particle size uniformity. Size control and reduction is generally determined by the laser settings; that the size and size distribution scales with laser fluence is well described. Conversely, the effect of the laser repetition rate on the final nanoparticle product in laser ablation is less well-documented, especially in the presence of stabilizers. Here, the influence of the laser repetition rate during laser ablation synthesis of silver nanoparticles in the presence of starch as a stabilizer was investigated. The increment of the repetition rate does not negatively influence the ablation efficiency, but rather shows increased productivity, causes a red-shift in the plasmon resonance peak of the silver-starch nanoparticles, an increase in mean particle size and size distribution, and a distinct lack of agglomerate formation. Optimal results were achieved at 10 Hz repetition rate, with a mean particle size of ~10 nm and a bandwidth of ~6 nm 'full width at half maximum' (FWHM). Stability measurements showed no significant changes in mean particle size or agglomeration or even flocculation. However, zeta potential measurements showed that optimal double layer charge is achieved at 30 Hz. Consequently, Ag-NP synthesis via the laser ablation synthesis in solution (LASiS) method in starch solution seems to be a trade-off between small size and narrow size distributions and inherent and long-term stability.

Chemometric analysis of lipase-catalyzed synthesis of xylitol esters in a solvent-free system.

Immobilized Candida antarctica lipase B-catalyzed esterification of xylitol and two fatty acids (capric and caproic acid) were studied in a solvent-free system. The Taguchi orthogonal array method based on three-level-four-variables with nine experiments was applied for the analysis and optimization of the reaction parameters including time, substrate molar ratio, amount of enzyme, and amount of molecular sieve. The obtained conversion was higher in the esterification of xylitol and capric acid with longer chain length. The optimum conditions derived via the Taguchi approach for the synthesis of xylitol caprate and xylitol caproate were reaction time, 29 and 18h; substrate molar ratio, 0.3 and 1.0; enzyme amount, 0.20 and 0.05g, and molecular sieve amount of 0.03g, respectively. The good correlation between the predicted conversions (74.18% and 61.23%) and the actual values (74.05% and 60.5%) shows that the model derived from the Taguchi orthogonal array can be used for optimization and better understanding of the effect of reaction parameters on the enzymatic synthesis of xylitol esters in a solvent-free system.

Preparation of silver nanoparticles in virgin coconut oil using laser ablation.

Laser ablation of a silver plate immersed in virgin coconut oil was carried out for fabrication of silver nanoparticles. A Nd:YAG laser at wavelengths of 1064 nm was used for ablation of the plate at different times. The virgin coconut oil allowed formation of nanoparticles with well-dispersed, uniform particle diameters that were stable for a reasonable length of time. The particle sizes and volume fraction of nanoparticles inside the solutions obtained at 15, 30, 45 min ablation times were 4.84, 5.18, 6.33 nm and 1.0 × 10(-8), 1.6 × 10(-8), 2.4 × 10(-8), respectively. The presented method for preparation of silver nanoparticles in virgin coconut oil is environmentally friendly and may be considered a green method.

Fabrication of silver nanoparticles dispersed in palm oil using laser ablation.

In this study we used a laser ablation technique for preparation of silver nanoparticles. The fabrication process was carried out by ablation of a silver plate immersed in palm oil. A pulsed Nd:YAG laser at a wavelength of 1064 nm was used for ablation of the plate at different times. The palm coconut oil allowed formation of nanoparticles with very small and uniform particle size, which are dispersed very homogeneously within the solution. The obtained particle sizes for 15 and 30 minute ablation times were 2.5 and 2 nm, respectively. Stability study shows that all of the samples remained stable for a reasonable period of time.