Journal of nanoscience and nanotechnology最新文献

Quantitatively studying the biodistribution and transformation of nanomaterials is of great importance for nanotoxicological evaluation. Recently, laser ablation inductively coupled plasma mass spectrometry has been employed to distinguish nanoparticles (NPs) with their dissolved ions in biological samples. The principle of the proposal is based on a hypothesis that the intact NPs sampled by laser ablation will generate discrete sharp pulses of signals in ICP-MS measurement, being totally different from the continuous, relatively lower signals generated by ions. However, it is still a controversy whether NPs could maintain their intactness during the laser ablation. This work found a way to exactly determine the number of NPs sampled for each LA-ICP-MS measurement. It made possible to reveal the signal profile of a single NP in LA-ICP-MS analysis. The results suggest that AuNR, AgNP and TIO₂ NP were broken into much smaller secondary NPs during the laser ablation, therefore generating continuous signals in the analyzer. There was a certain probability that the fragmentation of large-sized NP or multiple NPs by laser ablation was not sufficient, leaving some NPs unbroken or some secondary NPs with relatively large sizes to generate discrete pulses of signals in the analyzer. When the intactness of NPs during laser ablation cannot be assured, it is impossible to determine the attribution of mass spectrum signals. These findings compromise the reliability of distinguishing NPs from their dissolved ions by LA-ICP-MS.

This study investigated icariin (ICA) nanoparticles on angiogenesis in rats with pulmonary fibrosis and its mechanism. First, icariin solid nanoliposomes (ICA-SLN) were prepared. The in vitrorelease of icariin nanoparticles was determined using a UV-Vis spectrophotometer, after which the plasma concentration of icariin nanoparticles in rats was determined. The bioavailability of icariin nanoparticles was investigated, and the effect of icariin on angiogenesis of pulmonary fibrosis rats was re-observed. The results showed that the bioavailability of icariin in vivo was enhanced after nanomodification, which indicated that icariin solid nanoliposome was a good choice for oral sustained-release nanocarrier materials. in vivo experiments showed that icariin could significantly inhibit angiogenesis in rats with pulmonary fibrosis, and the inhibitory effect was related to the dose and time of action. Most importantly, this study provides the possibility of icariin as a targeted agent for future-targeted therapy.

We investigated the heat dissipation in heterostructure field-effect transistors (HFETs) using microRaman measurement of the temperature in active AIGaN/GaN. By varying the gate structure, the heat dissipation through the gate was clearly revealed. The temperature increased to 120 °C at the flat gate device although the inserted gate increased to only 37 °C. Our results showed that the inserted gate structure reduced the self-heating effect by three times compared to the flat gate structure. Temperature mapping using micro-Raman measurement confirmed that the temperature of the near gate area was lower than that of the near drain area. This indicated that the inserted gate electrode structure effectively prohibited self-heating effects.

Retinyl palmitate (RP) was added in monoolein (MO) cubic phase including decanoyl poly(ethyleneimine) (DePEI) and decanoyl gelatin (DeGel) in its water channel. RP, DePEI, and DeGel was incorporated In the cubic phase without structural disintegration, as confirmed by transmission electron microscopy. Differential scanning calorimetric and polarized optical microscopic analysis showed that adding the additives reduces phase transition temperature of cubic phase by 2 °C to 3 °C. The time-dependent chemical stability of RP added in the cubic phase was analyzed for 4 weeks at 5 °C, 20 °C, 30 °C, and 40 °C, using RP loaded in o/w emulsion as a control. The chemical stability of RP added in cubic phase containing DePEI and DeGel was somewhat higher as compared to the RP added in the cubic phase without DeGel/DePEI, possibly because DeGel/DePEI complex might shield RP from its environment by blocking the water channels inside the cubic phase. Moreover, the chemical stability of RP added in the cubic phase was comparatively higher than RP added in o/w emulsion.

The effect of the yttria-stabilized zirconia (YSZ) nanoparticle loading in an electro-less bath was considered as one of the vital synthesis variables for control Ni content and microstructure of prepared nanocomposite particles, which are two crucial factors to achieving high-performance SOFC anode. Nanocomposite particles were prepared using a simple electroless method without any expensive pretreatment of sensitizing by Sn²+ ions as well as activating by Pd²⁺ ions that are usually used to apply nickel coating on the surface of a non-conductive substrate. The process was performed by adding YSZ nanoparticles into NaOH solution, separating them from the solution by the centrifugal method, then providing several water-based nanofluids with different concentrations of activated YSZ nanoparticles, mixing them with NiCI₂ solution, followed by adding the hydrazine and then NaOH solution. X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis were used to analyze the prepared nanocomposite particles. It is observed that after adding YSZ nanoparticles into the NaOH solution, the pH of the solution varied gradually from a starting pH of 10.2 to 9. Also, by increasing the YSZ nanoparticles loading in the electroless bath from 76 mg/l to 126 mg/l, the grain size of Ni deposits, the Ni content and the average size of the prepared nanocomposite particles decreased. The electrochemical mechanism previously proposed for the nickel ion reduction was modified, and a novel analytical model was proposed for variation of the efficiency of Ni deposition with YSZ nanoparticles loading.

This research aimed to prepare ¹⁶⁶Dy₂O₃-iPSMA/¹⁶⁶Ho₂O₃-iPSMA nanoparticles (¹⁶⁶Dy₂O₃/¹⁶⁶Ho₂O₃-iPSMA NPs) and assess the radiation absorbed dose produced by the nanosystem to hepatic cancer cells by using experimental in vitro and in vivo biokinetic data. Dy₂O₃NPs were synthesized and functionalized with the prostate-specific membrane antigen inhibitor peptide (iPSMA). Fourier transform infrared (FTIR) spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DSL) and zeta potential analyses indicated the formation of Dy₂O₃-iPSMA NPs (46.11 ± 13.24 nm). After neutron activation, a stable ¹⁶⁶Dy₂O₃/¹⁶⁶Ho₂O₃- iPSMA nanosystem was obtained, which showed adequate affinity to the PSMA receptor in HepG2 cancer cells (K_d = 9.87 ± 2.27 nM). in vitro studies indicated high ¹⁶⁶Dy₂O₃/¹⁶⁶Ho₂O₃-iPSMA internalization in cancer cells, with high radiation doses to cell nuclei (107 Gy) and cytotoxic effects, resulting in a significant reduction in HepG2 cell viability (decreasing to 2.12 ± 0.31%). After intratumoral administration in mice, the nanosystem biokinetic profile indicated significant retention into the tumoral mass, producing ablative radiation doses (>70 Gy).

For the development of drugs that treat SARS-CoV-2, the fastest way is to find potential molecules from drugs already on the market. Unfortunately, there is currently no specific drug or treatment for COVID-19. Among all structural proteins in SARS-CoV, the spike protein is the main antigenic component responsible for inducing host immune responses, neutralizing antibodies, and/or protecting immunity against virus infection. Molecular docking is a technique used to predict whether a molecule will bind to another. It is usually a protein to another or a protein to a binding compound. Natural products are potential binders in several studies involving coronavirus. The structure of the ligand plays a fundamental role in its biological properties. The nuclear magnetic resonance technique is one of the most powerful tools for the structural determination of ligands from the origin of natural products. Nowadays, molecular modeling is an important accessory tool to experimentally got nuclear magnetic resonance data. In the present work, molecular docking studies aimed is to investigate the limiting affinities of trans-dehydrocrotonin molecule and to identify the main amino acid residues that could play a fundamental role in their mechanism of action of the SARS-CoV spike protein. Another aim of this work is all about to evaluate 10 hybrid functionalities, along with three base pairs using computational programs to discover which ones are more reliable with the experimental result the best computational method to study organic compounds. We compared the results between the mean absolute deviation (MAD) and root-mean-square deviation (RMSD) of the molecules, and the smallest number between them was the best result. The positions assumed by the ligands in the active site of the spike glycoprotein allow assuming associations with different local amino acids.

In this study, spinel NiCe_xFe_2-XO₄ (x = 0.0 - 0.5) nanoparticles (NPs) was synthesized by microwave combustion technique (MCT) utilizing the fuel of Aloe vera plant extract. The establishment of spinel cubic crystal structure was ensured by powder X-ray diffraction (PXRD) technique. The particles like nanostructured morphology were confirmed by high-resolution scanning electron microscope (HRSEM). Energy dispersive X-ray (EDX) studies confirmed the formation of spinel ferrite structure and ensured that no other elements were present. Magnetic parameters such as remanant magnetisation (Mr), coercivity (He) and saturation magnetization (Ms) were calculated from the magnetic hysteresis (M-H) loops, which exhibited ferromagnetic behaviour. The photocatalytic behavior was investigated by visible light treatment for the photocatalytic degradation (PCD) of rhodamine B (Rh-B) dye and the sample NiCe_0.3Fe_1.7O₄ exhibits higher PCD efficiency (93.88%) than other compositions. The antibacterial activities of gram-positive S. aureus, B. subtilis, gramnegative K. pneumonia and E. coli have been investigated using undoped and Ce³⁺ substituted NiFe₂O₄ NPs and observed higher activity, which indicated that, they can be used in the bio-medical applications.

Zinc sulfide nanospheres (ZnS NSs) were prepared by hydrothermal synthesis and graphene oxide (GO) was prepared by the Hummer's method. ZnS NSs-rGO/ITO electrode was synthesized by heat treatment at a certain temperature, which was used for the detailed electrochemical determination of levodopa (LD). Finally, they were annealed to form the ZnS NSs-rGO/ITO electrode for detecting levodopa (LD). The results reveal that the ZnS NSs with the diameter of ~1 μm are covered by rGO. The ZnS NSs-rGO/ITO electrode has a good sensitivity of 1.43 μA μM ^-1 for the determination of LD in the concentration range of 1-40 μM. Moreover, it also shows a good selectivity, reproducibility and stability. In order to verify the practicability, we also use the electrode to detect LD in human serum. The detection results also prove that the electrode can be used in real life.

Recently the applications of Poloxamers in drug development is promising as it facilitated the drug molecule for delivering to the correct place, at the correct time and in the correct amount. Poloxamers can form nanomicelles to encapsulate hydrophobic drugs in order to increase solubility, stability and facilitate delivery at target. In this context, the solubilization of anticonvulsant lamotrigine (LMN) drug in a chain of Poloxamers containing different polyethylene oxide and polypropylene oxide noieties were examined. The results showed better solubilization of LMN in Poloxamers contain low CMTs while poor with Poloxamers having high CMTs. Systematic investigation of two mixed Poloxamer nanomicelles (P407:P403 and P407:P105) for LMN bioavailability at body temperature (37 °C) were investigated. The solubility of LMN was enhanced in mixed P407:P403 nanomicelles with the amount of P403 and reduced in mixed P407:P105 nanomicelles with the amount of P105. LMN encapsulated mixed Poloxamer nanomicelles were found spherical in shape with ~25 nm D_h sizes. The In-Vitro release profiles of mixed Poloxamer nanomicelles demonstrated the biphasic model with initial burst release and then slowly release of LMN. Better biocompatibility of LMN in the mixed P407:P403 nanomicelles was confirmed with stability data. The results of this work were proven the mixed P407:P403 nanomicelles as efficient nanocarriers for LMN.