Applied Nanoscience最新文献

The present research reports the strain-specific interactions between probiotics and nanocurcumin using two widely used probiotic strains, Bacillus clausii and Lactobacillus rhamnosus GG. Bacillus clausii was characterized as a Gram-positive bacterium with variable growth patterns but exposure to nanocurcumin inhibited its growth, suggesting an antimicrobial effect. In contrast, Lactobacillus rhamnosus GG demonstrated enhanced growth in the presence of nanocurcumin, indicating a potential beneficial relationship. Despite a decrease in survival in simulated gastric fluid, Lactobacillus rhamnosus GG’s resilience in acidic environments highlights the challenges probiotics face in the gastrointestinal tract. These contrasting effects of nanocurcumin on the two strains emphasize the importance of understanding strain-specific interactions. The findings suggest that nanocurcumin could be utilized to optimize probiotic treatments, especially for gastrointestinal health, and warrant further research into its mechanisms and clinical applications.

Escalating use of amorphous silica nanowires (a-SiO_x NWs) in potential applications demonstrates the demand of novel processing techniques at nanoscale. Due to the imperfect structure and porous morphology, a-SiO_x NWs can be metal-modified which allows for electrical conduction under visible light. Unfortunately, their brittle nature at room temperature and nanometric-size make it demanding to precisely process and change shape from an elongated fiber to a sharply pointed tip. Here energetic electron beam (e-beam) irradiation of a-SiO_x and a-SiO_x NWs with gold-nanoparticles (Au-NPs) (Au–SiO_x NWs) is performed to develop diverse shaped nanoscale tips by optimizing e-beam parameters. Sharp amorphous tips (6 and 11 nm), extremely sharp Au-tips (4 and 6 nm), and relatively thick (16 and 18 nm) amorphous tips with average lengths of 50, 30, and 20 nm are formed at the centers of a-SiO_x and Au–SiO_x NWs when a tightly focused e-beam with beam spot size (~ 42 nm) equal to the diameters of NWs is centered at their axes and edge positions respectively. Au-tips thickening (4 or 6 to 22 nm) with reduction (20–16 nm) in length is observed when a uniform e-beam with beam spot size ~ 200 nm is employed. In-situ electron microscopy evaluation demonstrates that during e-beam processing, evaporation, diffusion, plastic flow, and dewetting are driven by positive curvature and e-beam activation effect. The combination of beam spot size and position can be used to tailor atomically sharp tips for wide applications, such as interconnects, biochemical sensing, scanning near-field optical microscopes, blue light emitters, and manipulations.

The rising threat of antimicrobial resistance in animal health necessitates the development of effective and sustainable alternatives to conventional antibiotics. The present study was taken up to explore the synergistic antibacterial potential of composite silver nanoparticles synthesized using Aloe barbadensis miller and Cymbopogon citratus. Phytochemical analysis was performed using the aqueous extracts of the selected plants. Silver nanoparticles (AgNPs) were synthesized from the respective plant extracts and different composites ratios of synthesized nanoparticles were prepared and characterized by UV–Vis spectrophotometry, scanning electron microscopy (SEM), dynamic light scattering (DLS) and inverted microscopy. Minimum inhibitory concentration (MIC) and antimicrobial efficacy of the test compounds was evaluated against common field isolates of Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. Phytochemical analysis revealed bioactive compounds saponins, tannins, phenols, flavonoids, proteins, glycosides and essential oils. Visible observation of color changes and UV–visible spectra exhibited plasmon peaks at 409 nm and 410 nm for individual plant AgNPs and composite at 418 nm. SEM showed spherical AgNPs with uniform distribution. DLS revealed average size of 50 nm. Inverted microscopy showed concentric ring structures. MIC showed appreciable inhibition and ABST using disk diffusion (Bauer-Kirby) revealed substantial zones of inhibition against above bacterial isolates. These findings suggest composite green nanoparticles could be a promising alternative for combating bacterial infections in animals upon confirming its efficacy on different clinical cases.

Utilizing an effective transformation method is fundamental in genetic and gene delivery studies. In this study, electrospray was evaluated as a simple, cost-effective and highly efficient approach for preparing monodispersed chitosan nanoparticles (CS NPs) carrying plasmid DNA (pDNA) and delivering them to bacteria. CS/pDNA NPs were prepared at three N/P ratios (molar ratio of chitosan nitrogens to DNA phosphates) of 3, 5, and 10. Size of nanoparticles was obtained as 323, 333, and 399 nm, respectively, using DLS. E. coli was made competent using CaCl₂ or CaCl₂–MgCl₂. Then, preformed CS/pDNA NPs, prepared using electrospray, were added to the heat-shocked bacteria. Alternatively, CS and pDNA solutions were mixed and directly electrosprayed on the bacteria. The results showed that direct electrospray of the particles provided more efficient transformation compared with transformation using heat shock (i.e. preformed NPs). Also, N/P ratios of 5 and 3 had maximum transformation efficiency when using heat shock (i.e. mean ± SD 1.23 ± 0.13 × 10⁷ CFU/µg on CaCl₂–MgCl₂-made competent bacteria) and direct electrospray (i.e. mean ± SD 8.79 (0.12) × 10⁹ CFU/µg on CaCl₂-made competent bacteria), respectively. Furthermore, the use of MgCl₂–CaCl₂ for making the bacteria competent proved more efficient than CaCl₂ alone in the transformation process. The findings highlight electrospray as a cost-effective alternative for bacterial transformation technology.

The use of green synthesis allowed for the creation of nanocomposite samples utilizing celery extract. PMMA was dissolved in acetone and then added to the synthesized SnO₂ at concentrations of 25%, 50%, 75%, and 100% µl. This was done after the SnO₂ was the result of the synthesis process. The names S1, S2, S3, and S4 have been assigned to these concentrations. Bio nanoparticles/polymer nanocomposite measurements employing X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis), and the Fourier transform infrared (FTIR) showed that the fourth concentration (S4) had the highest antibacterial activity, making it the most effective formulation. XRD reveals the tetragonal rutile phase structure in SnO₂ nanoparticles prepared by green synthesis method. The agglomeration effect and particle sizes cause this. TEM showed nanoparticles dispersed throughout the polymer with occasional agglomerations. Nanoscale dispersion was evident in the average particle size of 16.89 nm. FTIR study showed no chemical interaction because no new peaks formed and both SnO₂ and PMMA’s distinctive peaks remained constant. This implies that the compounds did not collide. The fact that the polymer was not dissolved in the SnO₂ is demonstrated by this fact, indicating that the mixing was entirely physical, as the SnO₂ peak at 610 cm⁻¹ shows no chemical changes in the material. The energy gap of this material can reach 3.85 eV, and its optical characteristics are better. Heat adaption allows the system to adjust to thermal imaging temperature variations. Higher thermal imaging temperatures reduce thermal stress and polymer expansion, indicating stability. Resistance to stretching and strain integrity indicate mechanical and thermal stability. Controlling thermal expansion in prosthetics prevents material deformation and ensures structural reliability. Tin dioxide (SnO₂) was tested on Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans active site residues using molecular docking. C. albicans had the lowest binding affinity (−6.1464 kcal/mol) and P. aeruginosa the highest. Due to hydrogen-ion interactions, the bond was maintained. Medical and thermal applications like biothermal imaging and prostheses could benefit from SnO₂-PMMA. This work fills a literature gap, proving its originality. Heat and mechanical stability without chemical reaction from celery extract with thermography for green PMMA polymer nanocomposites. Additionally, integrating in vitro testing and molecular docking to understand the microbial mechanism at the molecular level boosts the potential of these materials for medical applications, notably prostheses, which