Nano-Structures & Nano-Objects最新文献

This study aimed to verify the suitability of TiO₂ nanoparticles as nanomaterials in terms of crystallite size, microstrain and phase. The TiO₂ nanoparticles were tested experimentally in suspensions of mono ethylene glycol and distilled water (MEG-DW) at ratios of 10:90, 25:75, and 40:60. The nanoparticles were dispersed in the base liquid via a two-step process, resulting in the formation of TiO₂-3%/MEG-10, TiO₂-3%/MEG-25, and TiO₂-3%/MEG-40 nanofluids. The results revealed average crystallite sizes of approximately 20.10, 22.10, and 39.6 nm for the three nanofluid samples, as determined by the Scherrer equation, Williamson–Hall (W–H) plot, and TEM-ImageJ software. These results confirm that the TiO₂ nanoparticles meet the nanomaterial criteria with a sub-100 nm size. The microstrain analysis yielded values of 0.000020, 0.000299, and 0.001386 for the three samples and further investigation confirmed the presence of rutile. The high-temperature stability of the rutile phase makes the TiO₂ nanofluids suitable for use in industrial heating systems.

This work provides a unique strategy to anchor the individual properties of fluorophores, pharmacophores and receptors in a single platform using a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC). Notably, this approach counters the long-term dispute associated with the target-specific drug delivery of 5 fluorouracil and its intracellular tracing. Significantly, the luminescence property of the carbon dots (CDs) and the anticancer activity of the 5 fluorouracil drug are well preserved, even after their structural modification. The resulting nano-hybrid conjugate shows good thermal stability, photo-stability and can selectively guide the drug molecule toward cancer cells and remain nontoxic to noncancerous (hFB) cells. The conjugation of folic acid to the nanohybrid surface promoted the folate receptor-facilitated endocytosis to the folate-positive (HeLa) cell lines over the folate-negative (MCF-7) cells, which enhanced cellular uptake and corresponding better cell apoptosis results. Around 18.2% of cell apoptosis (late + early) values were recorded for the folate-conjugated formulation compared to the folate-less formulation (12.3%) and pure 5 FU drug (7.9%) by a flow cytometry study. Cell cycle analysis confirmed that the populations of HeLa cells in the S phase were around 18.20% and 29.8% for the folate-less formulation and the folate-conjugated formulation, indicating all the formulations can hinder the DNA replication and thymidylate synthesis by introducing cell cycle arrest in the S phase, just like the pure 5 FU drug. Also, the location of the drug molecule can be simultaneously traced because of the luminescent nature of the CDs. Therefore, the developed system has potential in target-specific drug delivery and long-term drug molecule tracking applications.

Selenium (Se) nanoparticles (SeNPs) express greater bioavailability, biocompatibility, and less toxicity than Se in ion form. SeNPs can be synthesized using different methods, including physics, chemistry, electrochemical plasma, and green synthesis using bacteria or plant extracts. In this study, the SeNPs were synthesized using a combination of Smilax glabra (SG) root extract as a reducing and stabilizing agent combined with electrochemical plasma (PLS), and their biological activities were examined for the first time. The obtained results showed that the SeNPs (SG+PLS) were successfully fabricated in a spherical shape with a size in the range of < 100 nm and maximal specific absorption spectrum at 310 nm. The SeNPs showed a free radical scavenging effect up to 94 % at a concentration of 125 µg/mL. Moreover, it expressed higher O₂^- radical scavenging activity compared to the SeNPs (SG) and SeNPs (PLS) alone at the test concentrations of 12.5, 25, and 125 µg/mL. The SeNPs also exhibited better antibacterial activity against E. coli, Staphylococcus aureus, and Candida albicans than those of SeNPs (SG) and SeNPs (PLS). Thus, one-step synthesized SeNPs (SG+PLS) with augmented biological activities had potential applications in foods and cosmetics.

Titanium dioxide (TiO₂)/nitrogen-doped graphene (NG) nanocomposite is prepared via a solvent-free hydrothermal reaction. The resulting TiO₂/NG materials exhibit a reduction of the band gap energy compared to pristine TiO₂ from 3.27 eV to 2.69 eV. These materials are characterized by scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). To prepare biopolymer films with photocatalytic properties, TiO₂ and NG are mixed with biodegradable chitosan and spin-coated on a silicon wafer. Film roughness and thickness are evaluated by atomic force microscopy (AFM). These films are then tested for ciprofloxacin photodegradation by irradiating with visible light. In comparison to the TiO₂/chitosan films, the addition of NG substantially enhances photodegradation efficiency by up to 34 % upon the addition of 5 % w/w of NG. Furthermore, this film is shown to be a good substrate for biomarker detection using laser desorption ionization mass spectrometry (LDI-MS). In summary, this nanocomposite-biopolymer film provides good photocatalytic activity towards ciprofloxacin degradation and enhances the ionization efficiency of peptide biomarkers in LDI-MS owing to high efficiency of laser absorption/desorption. This nanocomposite film might be useful for environmental-related and medical application.

In recent years, the sustainable utilization of waste materials has become a significant research area due to environmental concerns and resource scarcity. Graphene oxide nanoparticles (GONPs) are regarded as one of the most important materials due to their capacity to serve as a potentially scalable precursor to graphene and, more recently, as the most promising substance in biomedical research. This study successfully explores the synthesis of GONPs using recovered carbon black (rCB) derived from waste tires. The structural, morphological and antibacterial properties of the synthesised GONPs in this study were highlighted. The intensity ratio (I_D/I_G) from Raman spectroscopy analysis, obtained at 0.82, with FTIR spectral results shows the functional groups of hydroxyl, carboxyl and epoxy, similar to GO synthesised from pure graphite. TEM analysis showed that the surface morphology of the GONPs contains nanoparticles with a size of 44.95 nm. Despite using waste material, GONPs exhibited potential antibacterial activity towards the gram-positive and gram-negative bacteria tested in this study. The data presented here are novel and show the possibility of GONP synthesis from waste tires as a future cost-effective antibacterial agent.

The analyzed nanocomposites of this research have been fabricated by the sintering method, where different percentages of boron nitride, zinc oxide, aluminum oxide and titanium oxide have reinforced graphene. The percentages of additives were varied from 0 % to 5 %. An investigation of nanostructural observation, phase identification and structural analysis of graphene nanoparticles has been performed using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX) analysis and X-Ray Diffraction (XRD) analysis. The morphology of the synthesized materials was investigated by examining the FESEM pictures at different magnifications. The micrographs depict the hetero-materials' amalgamation, resulting in the formation of compacted particles that collectively exhibit a prominent bulbous morphology. The size and shape of different particles in the nanocomposites are visible from the FESEM images. The assays conducted by EDX have verified the presence of the necessary components, exhibiting a high degree of purity. Further insights about the nanocomposites have been obtained from Atomic Force Microscopy (AFM) analysis. AFM analysis revealed the surface roughness, which increased to 11.9 from 4.4 µm due to the addition of BN. The crystalline structure has been confirmed from the XRD analysis.

This investigation explores the versatile characteristics of environmentally friendly, green-synthesized zinc oxide (ZO) and Yttrium doped ZO nanoparticles (YDZO NPs). The focus is on assessing their efficacy in photocatalysis, antibacterial activity, and antioxidant properties. The NPs were produced using a sustainable synthesis method that incorporated phytochemicals derived from Murraya koenigii. The hexagonal structure of both ZO and YDZO NPs was confirmed through XRD results. TEM and SEM-EDS examinations unveiled spherical NPs with sizes ranging from 7 to 14 nm. Photocatalytic efficiency, evaluated through Rhodamine (RhB) dye degradation, demonstrated promising results for both ZO and YDZO NPs. Antibacterial assessments highlighted the NPs' ability to disrupt Bacillus subtilis and Escherichia coli, with the ZO NPs exhibiting superior antibacterial activity compared to their YDZO NPs. The antioxidant potential, assessed through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay, showcased the NPs' ability to scavenge free radicals, with the ZO NPs displaying enhanced activity attributed to the phytochemicals introduced during the green synthesis process. This research's innovation lies in the green synthesis of ZO and YDZO NPs, leveraging their distinct properties for synergistic applications. The study provides valuable insights into the potential future applications of these NPs, offering novel solutions for environmental remediation and biomedical uses.

A fundamental element of nanotechnology today is the advancement of sustainable, environmentally friendly and economically viable approaches to green synthesis of nanomaterials. In this study, fresh aqueous extract of pomegranate peels was used as reducing and stabilizing agents in a rapid and eco-friendly approach for the synthesis of zinc oxide nanoparticles (ZnO-NPs) and cobalt oxide nanoparticles (Co₃O₄-NPs). X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission electron microscope (TEM), Energy Dispersive Analysis of X-rays (EDX), and Fourier-transform Infrared Spectroscopy (FT-IR) were used to analyze the biosynthesized ZnO-NPs and Co₃O₄-NPs. XRD analysis confirmed the crystalline structures of ZnO-NPs and Co₃O₄-NPs as approximately 33.4 and 11.9 nm, respectively. SEM images showed distinct morphologies, while EDX and elemental mapping confirmed compositional integrity. FT-IR validated the characteristic functional groups present in both nanoparticles. TEM analysis provide the average particle size of ZnO-NPs and Co₃O₄-NPs were observed at 41.25 and 17.19 nm, respectively. The zeta potential of green synthesized ZnO-NPs and Co₃O₄-NPs were found to have a distinct peak at −12.5 and −16.3 mV, respectively. Both NPs have shown potent antimicrobial activity against four common pathogens, with increased antimicrobial activity against increasing concentrations of NPs. In vivo studies show a protective role for both ZnO-NPs and Co₃O₄-NPs against doxorubicin (DOX)-induced toxicity. In addition, Co₃O₄-NPs were effective against hepatotoxicity, nephrotoxicity, and endocrine disruption in male albino rats. Multi-technique investigation in this study offers a comprehensive understanding and indicates promising biological applications of ZnO-NPs and Co₃O₄-NPs.

This work focuses on the study of binary Al₂O₃-Y₂O₃-x and Al₂O₃-Ga₂O₃-x mixed oxides with varying Y₂O₃ or Ga₂O₃ nominal loading (x=25, 50) prepared by hydrothermal synthesis assisted by Triton X-100. The mixed oxides were used to prepare Ni-based (5 wt%) catalysts for the Water Gas Shift Reaction. The Al₂O₃ sample presented urchin-like hollow nanosphere morphology, which evolved to solid nanospheres with Y₂O₃ or Ga₂O₃ in the mixed oxides. The physicochemical characterization indicated good integration of the mixed oxides, especially on the low-content additive oxides. The theoretical results confirmed that Ga goes deeper into the alumina matrix than Y, partially explaining the XPS and HRTEM results in which the Ni dispersion was better in the Ni/AlGa-x samples. The FTIR in-situ measurements of the reaction allowed us to propose that the reaction occurs minimally through the carbonyl mechanism at low temperatures (<300 °C) and the formate mechanism at high temperatures (>300 °C).

The current study investigates the removal of Cu(II) ions from an aqueous solution through adsorption over amine-modified Fe(III)-doped-ZnO nanoparticles (FZO) beads. The physico-chemical properties of the synthesized FZO and FZO-M beads were determined using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-Ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of various adsorption parameters, including pH, temperature, dosage, contact time and initial metal concentration, were investigated for the removal of Cu(II) ions. The synthesized FZO and FZO-M beads showed the complete removal of Cu(II) ions from a 50 ppm aqueous solution at a dosage of 1 g/L, pH of 4 and temperature of 25 °C within 720 min. The formation of both cuprous oxide (Cu₂O) and cupric oxide (CuO) phases of copper oxides was achieved through the adsorption of Cu(II) over FZO and FZO-M beads, as revealed from FTIR, XRD and XPS analysis. The kinetics of the Cu(II) adsorption over both the synthesized beads follows a pseudo-second-order model, being faster for FZO-M beads than FZO beads. After amine modification of the FZO NPs, the maximum adsorption capacity of the FZO-M beads for the removal of Cu(II) ions was enhanced by 1.7 times and estimated to be 2144.5 mg/g, as per the Langmuir isotherm model. The Cu(II) removal mechanism, as identified by XPS analysis, revealed adsorption, complexation and copper oxides formation.