Applied Nanoscience最新文献

The demand for sustainable and eco-friendly materials has promoted studies over the years to explore different polymeric materials that meet requirements such as biodegradability and sustainability. In this context, biopolymer materials based on cellulose nanoparticles and starch from different botanical sources have been investigated, aiming to achieve satisfactory performance. The present study aims to develop and characterize cassava starch foams based on density, scanning electron microscopy (SEM), and three-point flexure tests, and to evaluate the effect of cellulose nanofibers obtained from palm mesocarp fibers using the ultrafine friction grinding method after different processing times, characterized by X-ray diffractometry (XRD), microscopy, and chemical composition, as a reinforcing filler. The chemical composition and scanning electron microscopy revealed the effectiveness of the cellulose isolation process, with  the analysis of the chemical composition revealing a cellulose content of 55.70% in the fibers after pulping and bleaching, in addition to changes in the visual characteristics of the material after the process aimed at isolating the cellulose. After grinding, XRD showed an increase in crystallinity (76.1% at the maximum grinding time), along with typical microscopy images of cellulose nanofibers. The analysis of the obtained nanocomposites provided insights into the role of these nanostructures in the thermo-expanded starch matrix, indicating that the nanofibers promoted changes such as an increase in mechanical properties and crystallinity, which contributed to improving overall mechanical performance. A 67.48% increase in flexural strength was achieved for the formulation with cellulose nanofibers that underwent 150 min of grinding, without causing major variations in density.

In recent years, the advancement of nanotechnology has created a great impact on the textile industry. Adhering to nanoscale levels, fabric surfaces have a wide variety of uses including ultraviolet (UV) protection, antibacterial resistance, wrinkle resistance, and flame retardance. In this work, selenium nanoparticles were synthesized and coated over three distinct cotton-woven fabrics (i.e.) organic, poplin, and muslin cotton fabrics. The respective coated fabrics were examined using X-ray diffraction analysis (XRD) which exhibits high crystallinity with an average size of 11 nm. The existence of cellulose peak has been confirmed from FTIR analysis. SEM images illustrate that the selenium nanoparticles have been coated on the respective fabrics. According to measurements of water contact angle, cotton fabric from muslin exhibits higher levels of hydrophobicity than other types. Colorfastness study has revealed that poplin cotton discloses higher color strength than others. Washing durability and tensile properties of the coated fabric has also been examined. The results of the antibacterial test showed that the presence of selenium nanoparticles significantly enhanced the antibacterial performance against three different bacterial strains, including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli using the disk diffusion method and its Zone of Inhibition (ZOI) were measured. Out of the three fabrics, poplin cotton has superior antibacterial properties.

Nanoceramics are distinguished by their exceptional mechanical qualities, including considerable strength, good toughness, and high fatigue resistance. Utilizing a green combustion technique, we successfully developed these nanoceramics and characterized them comprehensively using UV–Vis, XRD, EDAX, TEM, and XPS analyses. Our findings indicate the formation of nanocomposites with distinct cubic phases of NiO and ZrO₂, confirming their polycrystalline nature through SAED and XRD. The developed nanoceramics were innovatively applied for bacterial cell lysis to extract intracellular components. Nevertheless, the previously published microbial cell lysis approaches are insufficient for cell disruption due to the cell firmness. Thus, a nanoceramic mediated protein harvesting methodology was proposed from Bacillus subtilis CP-66 cells and promising results (0.447 mg/ml) were obtained within 25–50 min of the abstraction process. This nanoceramic is also explored for their broad-spectrum antibacterial activity against three human pathogenic bacterial strains. This work highlights the many uses of our nanoceramic material in advanced materials science and emphasizes its potential in industrial and healthcare applications.

Zinc oxide (ZnO) nanorods have gained a significant focus in research because of their impressive thermal stability and fascinating optical, chemical, and electrical properties. This work used the Chemical Bath Deposition method (CBD) to grow ZnO nanorods over solid surfaces like glass and Fluorine-doped tin oxide (FTO) substrates. Powder X-ray diffraction (P-XRD), UV–visible spectroscopy, and Scanning Electron Microscopy (SEM) based characterisation techniques were used to examine the phase, optical and morphological properties of ZnO nanorods. The objective of this study is to gather an understanding of the photo(electro)chemical and photocatalytic behaviour of CBD-synthesized ZnO nanorods on FTO substrate following noble metal deposition. We used gold (Au) and platinum (Pt) noble metals and deposited them over the ZnO surface using a photo-reduction technique. The photocatalytic and photo(electro)chemical response of the obtained nanostructures was studied.

SrTiO₃ is an interesting as well as evolving material with various applications in electronics, optics, and energy storage. This work includes synthesis and investigation of the different properties of strontium titanate nanoparticles and their effect on doping with rare-earth europium. Rare-earth functionalized materials are ruling the optoelectronic industry due to their characteristic emission properties. Known for its simplicity and cost-effectiveness, the combustion method is used for the successful synthesis of SrTiO₃ nanoparticles. The structural characteristics of the synthesized samples were accurately analyzed using X-ray diffraction (XRD) and found a particle-size difference from (10–15) nm with different dopant percentages of europium. Scanning electron microscopy (SEM) was performed to detect the morphology of the sample and obtain small moong beans-like agglomeration, and Raman spectroscopy was carried out to find the different bonding formations due to its structure. Photoluminescence (PL) spectroscopy was carried out to investigate the optical properties of both pure and Eu³⁺-doped SrTiO₃, revealing significant enhancements in luminescent efficiency due to doping concentration. Furthermore, the shift in the bandgap from (3.4 eV–3.2 eV) resulting from europium doping was examined using a UV–Vis spectrometer, demonstrating a noticeable change in optical absorption properties. The CIE parameter is calculated for an excitation wavelength of 395 nm and studied its emission spectra and rare emission in pink color. This study offers valuable insights into the potential applications of Eu³⁺doped SrTiO₃ nanoparticles in various technological fields, particularly optoelectronic devices like displays and advanced materials.

Hybrid nanomaterials-based polymer nanocomposites have achieved unique properties for multiple applications. This investigation focused on the impact of the synthesis of graphene oxide (GO) or silicon oxide (SiO2) nanomaterials (NM) with the combination of SiO2@GO as hybrid nanomaterials (HNMs). Either SiO₂ or GO and SiO@GO HNMs were utilized to reinforce blended polycaprolactone (PCL) and polyethyleneimine (PEI) to fabricate new PCL–PEI/SiO₂, PCL–PEI/GO, and PCL–PEI/SiO₂@GO nanocomposites using a developed acoustic-mixing-sonications procedure. Fourier transform infrared analysis reveals substantial interfacial bonds among blended polymers, SiO_2, nanoparticles, and GO nanosheets in nanocomposites_. The X-ray diffraction confirms the semi-crystalline nature of samples. Optical and field emission electron microscopy revealed homogenous and rough surfaces turned to smother with the contribution of nanomaterials. Incorporating NM and HNMs in the matrix presented transition elections at 240 nm, significantly improving compared with the blend polymer. HNMs contributions notably reduced the energy gap of the blended PCL–PEI polymers from 3.4 to 1.92 eV and 2.97 to 0.75 eV for allowed and forbidden transitions, respectively. HNMs showed the best efficacy against Gram-negative P. aeruginosa bacteria up to 30 mm and Gram-positive (E. faecalis) up to 16 mm compared to blended polymers. Using the MTT assay, the toxic effect of (PCL–PEI/SiO₂@GO) nanocomposites against breast cancer cells was notable, growing with concentration and toxic effect on cancer cells. Combining two nanomaterials presented results instead of one nanomaterial, making nanocomposites excellent candidates for several advanced applications, including optoelectronic devices, disinfectants, and antimicrobial materials.

Single-walled carbon nanotube (SWCNT) film/Si heterojunctions were obtained by depositing SWCNT films directly on a Si substrate by the floating catalyst chemical vapor deposition. The single-walled nature of the nanotubes was proven and confirmed by Raman and infrared spectroscopy, respectively. An additional ethanol post-growth treatment improved the properties of the heterojunctions by increasing densification of SWCNTs and decreasing their sheet resistance. Peaks positions of radial breathing mode obtained from the Raman mapping analysis demonstrated a random chirality (varying between armchair and zigzag) of tube structures and their very narrow diameter distribution, centered at ≈ 1.06 nm. This latter result was also confirmed by infrared spectroscopy. Properties of SWCNT/Si heterojunctions, such as ideality factor, Schottky barrier height, series resistance, SWCNT film work function and density of interface states are presented. To obtain the last two parameters by a self-consistent method, the intermediate nanolayer of silicon oxide between the SWCNT film and Si is considered. Impact of interface states and the native silicon oxide at the SWCNT/Si interface on the properties of heterojunctions is also discussed. Finally, such basic optoelectronic figures of merit as the responsivity, detectivity, and external quantum efficiency in the visible spectral range were determined and found to be comparable to the best reported for other SWCNT-based photodetectors.

Silver nanoparticles (AgNPs) have demonstrated exceptional antimicrobial activity, effectively targeting bacterial, fungal, and viral pathogens. This broad-spectrum antimicrobial efficacy makes AgNPs a valuable co-treatment alongside antibiotics, potentially mitigating the growing issue of antimicrobial resistance. Beyond their antimicrobial properties, AgNPs exhibit significant anticancer activity, employing mechanisms such as apoptosis induction and the inhibition of tumor growth and metastasis to selectively target cancer cells. Furthermore, AgNPs exhibit antioxidant potential of scavenging free radicals and reducing oxidative stress within biological systems. While AgNPs are non-toxic to humans at low concentrations, their toxicity is influenced by many factors besides concentration such as size, shape and surface charge. These multifaceted properties of AgNPs underscore the their potential in medical and therapeutic applications, such as wound dressings, catheters, medical devices, health supplement drink as well as targeted drug delivery. This study provides an overview of the characteristics of AgNPs, their diverse bioactivities, and the evidence supporting their mechanisms for effectively inhibiting bacterial growth, viral replication, cancer proliferation, and metastasis. Additionally, updated information on the toxicity, biosafety, and recent medical applications of AgNPs is discussed.

In recent years, concern about the rise of super-resistant bacteria and the environmental pollution associated with the inappropriate use of antibiotics and the waste generated during their production has grown significantly. In response to this problem, innovative solutions have been proposed, such as the use of silver nanoparticles (AgNP), recognized for their potent antimicrobial properties against a wide range of organisms, including pathogenic bacteria. This study presents an innovative and environmentally friendly approach to the synthesis of silver nanoparticles using sonotrode, where Cannabis sativa extract acts as a reducing agent, replacing sodium borohydride (NaBH₄), a commonly used but highly polluting and carcinogenic chemical reagent. The research explored the use of different concentrations of C. sativa in the green synthesis of AgNP, evaluating their physicochemical properties and antimicrobial efficacy. To confirm the concentration, chemical composition and structural features of the nanoparticles, techniques such as atomic absorption spectroscopy (AAS), dispersion X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were employed. Scanning electron microscopy (SEM) analysis revealed details about the morphology and average size of the silver nanoparticles. Finally, the antibacterial efficacy of the nanoparticles was evaluated by the agar dilution method, underlining the potential of this innovative approach in the fight against resistant bacteria and environmental pollution. The results obtained show that the 0.5% Bio-AgNPs samples produced 53% nanoparticles, while the 2% Bio-AgNPs produced 87%. EDX analysis confirmed the presence of silver (Ag), while FTIR spectra indicated the presence of phenols, flavonoids, amino groups, alkanes, and alkenes. Ag–Ag metal bond vibrations were observed in Raman spectroscopy, and SEM analysis revealed the formation of predominantly spherical nanoparticles with sizes less than 50 nm. Furthermore, bacteriological assays demonstrated that 50, 25, and 12.5 ppm concentrations of C-AgNPs and Bio-AgNPs showed significant inhibition, highlighting that 2% C. sativa provided the best antimicrobial property. The observed biocompatibility, successful reduction of silver nitrate, and remarkable antibacterial efficacy of the synthesized nanoparticles underline the great potential of green synthesis strategies in nanoparticle production. These findings suggest that nanoparticles synthesized using this method are not only effective, but also compatible with an environmentally sustainable approach.

This study presents a method for synthesizing superparamagnetic nanoparticles through the co-precipitation method, with a coating of tetrahydroxy-1,4-quinone (THQ). The diameter of the magnetite nanoparticles (MNPs) covered with THQ varied depending on the recovery method applied. When collected through magnetic decantation, they exhibited an average diameter of 15 ± 3 nm, while centrifugation of the supernatant further reduced the diameter to 12 ± 3 nm. In contrast, the uncoated MNPs had an average diameter of 17 ± 5 nm. The smaller MNPs coated with THQ displayed very low magnetic hysteresis and demonstrated superparamagnetic behavior, indicated by a blocking temperature of less than 300 K. Characterization of both the coated and uncoated MNPs encompassed structural, morphological, size, and magnetic property analyses using X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. Fourier-transform infrared spectroscopy (FT-IR) and UV–Vis spectroscopy were employed to investigate the chemical interaction between THQ and the MNPs. In addition, cyclic voltammetry was used to compare the electrochemical changes of THQ, MNPs, and MNPs coated with THQ.