Spherical Nanoparticles Research Articles

Facile two step approach of Chitosan/Nickel/ZrO2 bio-nanocomposite and investigation of their antimicrobial activities against Escherichiacoli

Chitosan nanoparticles (CH NPs), ZrO2, Ni/ZrO2. CH/ZrO2 and CH/Ni/ZrO2 complex have been synthesized then its antibacterial mechanisms of nanomaterials against Escherichia coli (E. coli) was evaluated by agar well diffusion and systematically analyzed by measuring the diameter of the inhibition zone. X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra and Energy dispersive X-ray (EDX) results demonstrated the formation of CH/Ni/ZrO2 matrix. Also, the crystalline sizes were found to be 15, 13, 10 and 8 nm for ZrO2, Ni/ZrO2, CH/ZrO2 and CH/Ni/ZrO2 respectively. The FTIR spectrum revealed bands ranging from 400 to 800 cm−1, indicating the presence of metal–oxygen bonds. Additionally, bands at 1620, 1523, and 1300 cm−1 suggested the presence of amide groups, confirming the presence of CH in the produced CH/Ni/ZrO2 nanocomposite. In SEM analysis, the irregular spherical nanoparticles are observed in case ZrO2 and CH/ZrO2 samples, while spherical with an oval-shaped structure are observed in case of Ni/ZrO2 and CH/Ni/ZrO2 sample. Mean diameter of inhibition zone were observed to be 13 ± 2.51, 12 ± 2.08, 16 ± 1.3 mm,17 ± 2.3 mm and 18 ± 0.8 nm for CH, ZrO2, Ni/ZrO2, CH/ZrO2 and CH/Ni/ZrO2 respectively. The eco-friendly and cost-effective synthesis of Chitosan assisted Ni/ZrO2 NPs can be utilized as an effective antibacterial agent.

Biofabrication of GO-Ag nanocomposite using Cucumis callosus (kachri) fruits: Enhanced antibacterial properties and green synthesis approach.

This study presents a novel, environmentally sustainable method for the synthesis of graphene oxide (GO) sheets decorated uniformly with silver nanoparticles (Ag NPs) ranging in size from 4 to 34 nm. The reduction of AgNO3 is achieved using an extract derived from Cucumis callosus fruit, which serves as a dual-function stabilizing and reducing agent. Cucumis callosus, belonging to the Cucurbitaceae family and native to regions such as India, South America, Thailand, Africa, and Egypt, is recognized for its substantial nutritional and medicinal value, encompassing antioxidant, antidiabetic, anticancer, and anti-inflammatory properties. In this study, we explore the utilization of Cucumis callosus extract for the first time in synthesizing Ag NPs, employing a green synthesis approach to produce GO-Ag nanocomposites. Comprehensive characterization techniques confirm the structural integrity and quality of the synthesized nanocomposites. The antibacterial efficacy of the green-synthesized Ag-decorated GO nanocomposites was evaluated using the disk diffusion method against Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) bacteria at varying dosages. The nanocomposites demonstrated dose-dependent antibacterial activity against both bacterial strains, with a notably heightened effect observed against Gram-negative bacteria. These findings underscore the potential of Cucumis callosus as a promising candidate for the sustainable preparation of GO-Ag nanocomposites with enhanced antibacterial properties, suitable for various biomedical and environmental applications. RESEARCH HIGHLIGHTS: This work presents a simple, environmentally free, and cost-effective green synthesis method to decorate uniformly small (4-34 nm) spherical Ag NPs on the GO sheets. Ag NPs were produced by reducing AgNO3 using Cucumis callosus fruit extract as a stabilizing and reducing agent. The nanocomposites show dosage-dependent antibacterial activities against both Gram-positive and Gram-negative bacteria, but the antibacterial effect is higher against the Gram-negative bacteria. Synthesis of these nanocomposites via the green route using an herbal plant/fruit like Cucumis callosus will benefit the medical industry.

SnO2QDs: Photophysical properties, photocatalytic activity, mineralization financial cost and recycling process during industrial effluent treatment

This study investigates the synthesis, characterization, and photocatalytic performance of pure and titanium-doped tin dioxide quantum dots (SnO2QDs) prepared via a sonochemical method. The structural and morphological properties were thoroughly examined using XRD, FTIR, SEM-EDX, HRTEM, UV-DRS, and BET surface area analysis. XRD confirmed the formation of tetragonal SnO2 with high phase purity and average crystallite sizes of 2.95 nm for SnO2QD1 (calcined at 270 °C) and 8.36 nm for SnO2QD2 (calcined at 480 °C). Titanium doping was achieved without altering the SnO2 crystalline structure, as evidenced by FTIR spectra showing characteristic vibrational modes and hydroxyl groups. HRTEM images revealed spherical nanoparticles with diameters of 3.2 nm for SnO2QD1 and 9.7 nm for SnO2QD2, supported by SAED patterns confirming their polycrystalline nature. The photocatalytic efficiency was evaluated through the degradation of Reactive Yellow 145 dye under Xenon lamp irradiation. SnO2QD1 exhibited superior photocatalytic activity with a rate constant (k) of 6.94 × 10−3 s−1, achieving 80 % dye degradation in 105 min, compared to SnO2QD2 with a k of 4.50 × 10−3 s−1 and 83 % degradation in 120 min. Titanium doping further enhanced the photocatalytic performance, with SnO2QDT1 (1 % Ti) showing a k of 9.89 × 10−3 s−1 and 80 % degradation in just 90 min, three times more efficient than SnO2QDT2 (9 % Ti). BET analysis indicated a significant reduction in surface area with increased calcination temperature, from 154 m2/g for SnO2QD1 to 86 m2/g for SnO2QD2. The bandgap energies, determined via UV-DRS, were 3.30 eV for SnO2QD1 and 3.34 eV for SnO2QD2, slightly reduced in Ti-doped samples, enhancing visible light absorption. The SnO2QDs demonstrated excellent recyclability, maintaining photocatalytic activity over eight reuse cycles. Economic analysis based on Saudi Arabian electricity tariffs highlighted the cost-effectiveness of SnO2QD1, offering a 5.2 % reduction in energy consumption compared to SnO2QD2. These findings position SnO2QDs as highly efficient and sustainable photocatalysts for industrial wastewater treatment applications.

Gypenoside A-loaded mPEG-PLGA nanoparticles ameliorate high-glucose-induced retinal microvasculopathy by inhibiting ferroptosis

Diabetic retinopathy (DR) is one of the chronic microvascular complications of type 2 diabetes mellitus (T2DM), which will cause retinal detachment and blindness without ideal therapies. Gypenoside A (GPA) are the main bioactive compound from Gynostemma pentaphyllum, and have various pharmacological effects. However, it suffered from poor bioavailability and potential cardiotoxicity in the clinical application. To overcome those limitations, in this study, nearly spherical nanoparticles (GPA-NP) with a mean particle size of 140.6 ± 22.4 nm were prepared by encapsulating GPA into mPEG-PLGA. This encapsulation efficiency was 84.4 ± 6.9 %, and the drug load was 4.02 %±0.35 %. The results showed that GPA-NP displayed more prolonged GPA release and higher bioavailability in vitro than GPA. GPA-NP obviously reduced the levels of oxidative stress markers and inflammatory cytokines in both retinal tissues of DR mice and high glucose-exposed HRMEC better than GPA alone. Mechanismly, GPA blocked the Nrf2-Keap1 interaction by binding with Kelch domain of Keap1 via alkyl and hydrogen bonds. Therefore, GPA-NP exerted more potent protectivity effects against high glucose-induced retinal microvascular endothelial ferroptosis in vitro and in vivo by activating Nrf2/HO-1/GPX4 pathway. It could be a promising therapeutic agent for preventing DR.

Assessing anticancer properties of PEGylated platinum nanoparticles on human breast cancer cell lines using in-vitro assays

This study describes the in-vitro cytotoxic effects of PEG-400 (Polyethylene glycol-400)-capped platinum nanoparticles (PEGylated Pt NPs) on both normal and cancer cell lines. Structural characterization was carried out using x-ray diffraction and Raman spectroscopy with an average crystallite size 5.7 nm, and morphological assessment using Scanning electron microscopy (SEM) revealed the presence of spherical platinum nanoparticles. The results of energy-dispersive x-ray spectroscopy (EDX) showed a higher percentage fraction of platinum content by weight, along with carbon and oxygen, which are expected from the capping agent, confirming the purity of the platinum sample. The dynamic light scattering experiment revealed an average hydrodynamic diameter of 353.6 nm for the PEGylated Pt NPs. The cytotoxicity profile of PEGylated Pt NPs was assessed on a normal cell line (L929) and a breast cancer cell line (MCF-7) using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The results revealed an IC50 of 79.18 μg ml−1 on the cancer cell line and non-toxic behaviour on the normal cell line. In the dual staining apoptosis assay, it was observed that the mortality of cells cultured in conjunction with platinum nanoparticles intensified and the proliferative activity of MCF-7 cells gradually diminished over time in correlation with the increasing concentration of the PEGylated Pt NPs sample. The in vitro DCFH-DA assay for oxidative stress assessment in nanoparticle-treated cells unveiled the mechanistic background of the anticancer activity of PEGylated platinum nanoparticles as ROS-assisted mitochondrial dysfunction.

Tailoring iron hexadecafluorophthalocyanine/GO nanocomposite separators for polysulfide adsorption and enabling fast electrochemical kinetics of Li-S batteries

The cycling stability of lithium-sulfur batteries is significantly compromised by the shuttle effect. Herein, we employed a preformed process to successfully load spherical nanoparticles of Iron hexadecafluorophthalocyanine (FePcF16) with sizes between 10 and 20 nm onto oxidized graphene sheets. The FePcF16 spherical particles with lithium and sulfur-affinitive sites maximally expose catalytically active sites, facilitating effective adsorption and catalysis of polysulfides (LiPSs). Density-functional theory (DFT) calculations suggest that the electron-rich fluorine substituents enhance the conjugation effect of FePcF16, facilitating electronic communication between the catalyst and graphene oxide (GO), achieving precise modulation of the electronic structure of Fe-N4 active centers. The electrochemical analysis demonstrates that the nanostructured and Fe-N4 site-containing FePcF16 integrated with the robust two-dimensional graphene structure synergistically facilitates both redox reactions and lithium affinity effects. Consequently, in extended cycling tests at 2 C, the initial discharge-specific capacity reached 857.7 mAh g−1. After 500 cycles, the capacity remained at 737.7 mAh g−1, with a minimal capacity decay rate of only 0.028 % per cycle.

Tailoring multi-type nanoprecipitates in high-entropy alloys towards superior tensile properties at cryogenic temperatures

In this work, the quasi-static tensile properties in the face-centered cubic-based Al0.5Cr0.9FeNi2.5V0.2 HEAs containing two types of heterogeneous nanoprecipitates, i.e., dual-lamellar and spherical nanoprecipitates, at ambient (293 K) and liquid nitrogen (77 K) temperatures are thoroughly investigated. The microstructure formed by aging at 873 K comprises L12 and body-centered cubic dual-lamellar (DL) nanoprecipitates. In contrast, aging at 773 K results in solely spherical L12 nanoparticles. Both nanoprecipitates enhance mechanical strength as temperatures drop to 77 K; however, the DL nanoprecipitates additionally boost the work hardening rate, whereas the spherical nanoparticles notably improve ductility. To investigate the underlying deformation mechanisms, we perform interrupted mechanical tests and microstructure characterizations at various strains. The DL nanoprecipitates are observed to go through a multistage work hardening rate response by gradually introducing new boundaries to block dislocation motion, activating the stacking fault (SF) networks, and forming Lomer–Cottrell locks. A combination of interface hardening, dislocation hardening, SF-induced hardening, and precipitation hardening in DL samples leads to stronger hetero-deformation-induced hardening at cryogenic temperatures. In comparison, while samples with only spherical nanoparticles exhibit a monotonous decrease in the work-hardening rate, the spherical nanoparticles can be sheared by dislocations, effectively alleviating strain concentration and thereby enhancing ductility at cryogenic temperatures. Overall, this work provides practical design principles of nanoprecipitates for fine-tuning the balance of strength and ductility in FCC-based HEAs at cryogenic temperatures.

Oppositely charged polymer-surfactant nanoparticles stabilized by triblock copolymers for enhanced oil loading

When oppositely charged polymers and surfactants combine, they can form a concentrated phase rich in micelles interconnected by polymer chains. Dispersing this concentrated phase as nanoparticles in an aqueous media can be a way to load and deliver hydrophobic ingredients. This study employed triblock copolymers of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), EOxPOyEOx, also known as poloxamers or pluronics, to disperse the concentrated phase, forming nanoparticles of aggregated micelles connected by the polyion chains. We showed that nanoparticles formed by hexadecyltrimethylammonium bromide (CTAB), poly(acrylic acid) (PAA), and different EOxPOyEOx copolymers can enhance the loading of oily ingredients compared to pure surfactant micelles. Dispersions with 1.6 wt% of nanoparticles exhibited water-like viscosity and loaded up to 0.48 wt% of oil. Characterization techniques, including dynamic light scattering (DLS), electrophoretic mobility, small-angle X-ray scattering (SAXS), and cryogenic transmission electronic microscopy (cryo-TEM), revealed positively charged spherical 50–180 nm nanoparticles with a core formed by concentrated micelles, that were stable for at least 4 months. Variations in the EO and PO block lengths did not impact morphology, showing that different EOxPOyEOx copolymers were suitable for dispersing the nanoparticles. Increasing EO block length size decreased the diameter of nanoparticles and enhanced stability, providing a means to control their properties. In conclusion, nanoparticles formed by oppositely charged polymer-surfactant mixtures and stabilized by triblock copolymers showed potential for applications, such as sprays, due to their effective oil loading, high stability, and facile preparation.

Voltammetric Sensor Based on Titania Nanoparticles Synthesized with Aloe vera Extract for the Quantification of Dithiophosphates in Industrial and Environmental Samples

In this work, TiO2 spherical nanoparticles with a mean diameter of 10.08 nm (SD = 4.54 nm) were synthesized using Aloe vera extract. Rutile, brookite, and anatase crystalline phases were identified. The surface morphology of a carbon paste electrode does not change in the presence of nanoparticles; however, the surface chemical composition does. The voltammetric response to dicresyl dithiophosphate was higher when the electrode was modified with TiO2 nanoparticles. After an electrochemical response study from pH 1.0 to 12.0, pH 7.0 was selected for the electroanalysis. The electroactive area of the modified sensor was 0.036 cm2, while it was 0.026 cm2 for the bare electrode. The oxidation process showed mixed adsorption-diffusion control. The charge transfer resistance of the modified sensor (530.1 Ω, SD = 4.08 Ω) was much lower than that of the bare electrode (4298 Ω, SD = 8.53 Ω). The linear quantitative range by square wave voltammetry was from 5 to 150 μmol/L, with a limit of detection of 1.89 μmol/L and a limit of quantification of 6.26 μmol/L under optimal pulse parameters of 50 Hz frequency, 1 mV step potential, and 25 mV pulse amplitude. The sensor response was repeatable and reproducible over 30 days. The results on real flotation and synthetically contaminated soil samples were statistically equivalent to those obtained by UV-vis spectrophotometry. A dithiocarbamate showed an interfering effect on the sensor response to dithiophosphate.

Evaluation of heat transfer for unsteady thin film flow of mono and hybrid nanomaterials with five different shape features

Recent advancement in nanotechnology brings the idea of hybrid nanomaterials which offer distinguish applications in thermal reservoirs, cooling systems, energy applications, chemical engineering, vehicle engines etc. The understating of shape features for hybrid nanomaterials is quite essential as such consequences highly influenced various thermal properties like viscosity, thermal conductivity, optical properties, stability etc. The objective of current work is to examine heat transfer analysis due to thin film unsteady flow of hybrid nanofluid. The properties of hybrid nanofluid are justified for entertaining the copper (Cu), aluminium oxide (Al2O3) nanoparticles with water (H2O) base fluid. Additionally, applications of viscous dissipation, heat source and nonlinear radiated effects are attributed to current flow problem. The thermal properties of nanoparticles are examined in presence of five shape features consisting of blades, platelets, cylinders, bricks and spheres. Numerical simulations of problem are performed via Runge-Kutta-Fehlberg method. Comparative heat transfer is performed for mono nanofluid (Cu/H2O) and hybrid nanofluid (Cu−Al2O3)//H2O. It has been observed that heat transfer enhancement is more stable for cylindrical particles as compared to spherical nanoparticles. The skin friction enhances due to Hartmann number for both mono nanofluid (MNF) and hybrid nanofluid (HNF). Current results claim applications in coating thin films, lubrication systems, improving the thermal efficiency in thermal and industrial systems, heat exchangers, cooling systems etc.

Green synthesis and characterization of titanium dioxide nanoparticles and their photocatalytic activity

In this study, we compared two low-temperature synthesis procedures for the large-scale production of titania nanoparticles (NPs). The first takes place in an aqueous medium with an acidic environment, by using a triblock polymer surfactant (Pluronic 123). The second involves a polycondensation reaction of alkoxide precursors at 70 °C in a water-in-oil (W/O) microemulsion with a volume ratio of 1:1, using cetylpyridinium bromide (CPB) as a cationic surfactant. The morphological and structural characterization of the samples was carried out through Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The photoactivity of the nanostructured titania was evaluated by measuring the photodegradation of Methylene Blue (MB). The solvent-free synthetic approach provided spherical titania nanoparticles mainly constituted by rutile crystallites with a very good synthetic yield. However, the photodegradation rate of MB for such titania nanoparticles ranges from 30 % to 40 %, after 1h under solar irradiation. Conversely, titania nanoparticles obtained through microemulsion synthesis show a photodegradation rate of more than 90 % comparable to titania P25. This high-yield synthesis leads to the formation of TiO2 nanoparticles characterized by small crystallite aggregates (rutile and anatase).

Freeze-Driven Adsorption of Oligonucleotides with polyA-Anchors on Au@Pt Nanozyme.

A promising and sought-after class of nanozymes for various applications is Pt-containing nanozymes, primarily Au@Pt, due to their easy preparation and remarkable catalytic properties. This study aimed to explore the freeze-thaw method for functionalizing Pt-containing nanozymes with oligonucleotides featuring a polyadenine anchor. Spherical gold nanoparticles ([Au]NPs) were synthesized and subsequently used as seeds to produce urchin-like Au@Pt nanoparticles ([Au@Pt]NPs) with an average diameter of 29.8 nm. The nanoparticles were conjugated with a series of non-thiolated DNA oligonucleotides, each consisting of three parts: a 5'-polyadenine anchor (An, with n = 3, 5, 7, 10; triple-branched A3, or triple-branched A5), a random sequence of 23 nucleotides, and a linear polyT block consisting of seven deoxythymine residues. The resulting conjugates were characterized using transmission electron microscopy, spectroscopy, dynamic light scattering, and emission detection of the fluorescent label at the 3'-end of each oligonucleotide. The stability of the conjugates was found to depend on the type of oligonucleotide, with decreased stability in the row of [Au@Pt]NP conjugates with A7 > A5 > 3A3 > 3A5 > A10 > A3 anchors. These [Au@Pt]NP-oligonucleotide conjugates were further evaluated using lateral flow test strips to assess fluorescein-specific binding and peroxidase-like catalytic activity. Conjugates with A3, A5, A7, and 3A3 anchors showed the highest levels of signals of bound labels on test strips, exceeding conjugates in sensitivity by up to nine times. These findings hold significant potential for broad application in bioanalytical systems.

Optimization of optical properties of nanocomposite films incorporating CWO and ITO nanoparticles for energy-saving window applications

Cesium tungsten oxide (CWO) and indium tin oxide (ITO) nanoparticles are potential candidates for application in energy-saving windows. However, most optical studies on these nanocomposite films lack systematic evaluation and design methods. In this work, the optical properties of spherical and cylindrical CWO and ITO nanoparticles under different geometric parameters based on the Lorenz–Mie and T-matrix theories are investigated, and spectral responses of CWO-PDMS and ITO-PDMS windows are calculated by solving the radiative transfer equation (RTE) using the Monte Carlo method. By evaluating and optimizing the geometric parameters of the nanocomposite films, energy-saving windows exhibit excellent optical performance, with a visible light transmittance that meets the indoor needs of the human eye (Tlum is about 0.6), and can shield most near-infrared light, especially CWO-PDMS windows (TNIR=0.04). Finally, a building energy consumption simulation analysis based on Energy Plus is conducted in three different cities: Jinan, Hong Kong, and Singapore. The results indicate that by adjusting the geometric parameters of nanoparticles, energy-saving windows can effectively reduce energy consumption in tropical and subtropical regions. This work provides guidance for the subsequent commercialization and experimental analysis of spectral selective composite films.

Microwaves in ferromagnetic composites Fe/Epoxy with aggregates of nanoparticles: Theory and experiment

Microwave transmission through plates of a composite material containing spherical Fe nanoparticles in an epoxyamine matrix and reflection from plates have been studied. Measurements were carried out at the frequencies from 26 to 32 GHz in the magnetic fields up to 12 kOe. The ferromagnetic resonance phenomenon in the composite has been investigated. The theory of electromagnetic waves transmitting through a composite material containing ferromagnetic particles, taking into account aggregating the particles, has been developed. A good agreement of calculation results and experimentally obtained field dependences of the transmission and reflection coefficients, as well as microwaves dissipation, has been achieved.

A Minimal PBPK Model Describes the Differential Disposition of Silica Nanoparticles In Vivo.

Nanoparticles (NPs) have emerged as promising candidates for drug delivery due to their tunable physical and chemical properties. Among these, silica nanoparticles (SiNPs) are particularly valued for their biocompatibility and adaptability in applications like drug delivery and medical imaging. However, predicting SiNP biodistribution and clearance remains a significant challenge. To address this, we developed a minimal physiologically-based pharmacokinetic (mPBPK) model to simulate the systemic disposition of SiNPs, calibrated using in vivo PK data from mice. The model assesses how variations in surface charge, size, porosity, and geometry influence SiNP biodistribution across key organs, including the kidneys, lungs, liver, and spleen. A global sensitivity analysis identified the most influential parameters, with the unbound fraction and elimination rate constants for the kidneys and MPS emerging as critical determinants of SiNP clearance. Non-compartmental analysis (NCA) further revealed that aminated SiNPs exhibit high accumulation in the liver, spleen, and kidneys, while mesoporous SiNPs primarily accumulate in the lungs. Rod-shaped SiNPs showed faster clearance compared to spherical NPs. The mPBPK model was extrapolated to predict SiNP behavior in humans, yielding strong predictive accuracy with Pearson correlation coefficients of 0.98 for mice and 0.92 for humans. This model provides a robust framework for predicting the pharmacokinetics of diverse SiNPs, offering valuable insights for optimizing NP-based drug delivery systems and guiding the translation of these therapies from preclinical models to human applications.

Myco-Biosynthesis of Silver Nanoparticles, Optimization, Characterization, and In Silico Anticancer Activities by Molecular Docking Approach against Hepatic and Breast Cancer.

This study explored the green synthesis of silver nanoparticles (AgNPs) using the extracellular filtrate of Fusarium oxysporum as a reducing agent and evaluated their antitumor potential through in vitro and in silico approaches. The biosynthesis of AgNPs was monitored by visual observation of the color change and confirmed by UV-Vis spectroscopy, revealing a characteristic peak at 418 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses showed spherical nanoparticles ranging from 6.53 to 21.84 nm in size, with stable colloidal behavior and a negative zeta potential of -15.5 mV. Selected area electron diffraction (SAED) confirmed the crystalline nature of the AgNPs, whereas energy-dispersive X-ray (EDX) indicated the presence of elemental silver at 34.35%. A face-centered central composite design (FCCD) was employed to optimize the biosynthesis process, yielding a maximum AgNPs yield of 96.77 µg/mL under the optimized conditions. The antitumor efficacy of AgNPs against MCF-7 and HepG2 cancer cell lines was assessed, with IC50 values of 35.4 µg/mL and 7.6 µg/mL, respectively. Molecular docking revealed interactions between Ag metal and key amino acids of BCL-2 (B-cell lymphoma-2) and FGF19 (fibroblast growth factor 19), consistent with in vitro data. These findings highlight the potential of biologically derived AgNPs as promising therapeutic agents for cancer treatment and demonstrate the utility of these methods for understanding the reaction mechanisms and optimizing nanomaterial synthesis.

Magnetic field enhanced terahertz emission from metallic nanostructures with response to laser spatial profile distribution

This communication proposes an analytical model that exhibits terahertz (THz) radiation generation from spatially corrugated noble-metal spherical and cylindrical nanoparticles (NPs) placed under the influence of an externally applied static magnetic field. This scheme involves the resonant excitation of THz radiation through the beat-wave of two lasers in the presence of ponderomotive nonlinearities. Effect of magnetic field as well as laser intensity profiles, which include super, cosh, flat-top and ring-shaped Gaussian profiles, have been investigated. The incorporation of the magnetic field induces substantially more dynamic laser-metal coupling and influences the surface plasmon resonance condition associated with electrons of the NPs, thereby leading to stronger THz emission. Our results also demonstrate that the spatial profile of the laser affects the THz output, as it impacts the excitation and dynamics of the NPs. Additionally, we find that both the shape, size and interparticle-separation of NPs play crucial roles in enhancing THz generation. Furthermore, we explore the effects of varying other parameters like electric field strength and beam waist of incident lasers. These findings provide valuable insights for the design and optimization of THz sources based on NP systems, offering new avenues for applications in spectroscopy, imaging, communication and biomedical sciences.

ZrO2 nanoparticles for effective dye degradation in wastewater: Synthesis, characterization, and photocatalytic performance under sunlight

The study addresses the critical issue of water contamination, focusing on the photodegradation of methylene blue (MB) dye as industrial waste. A novel method is presented to synthesize zirconium dioxide (ZrO2) nanoparticles (NPs) using zirconium hydrogen phosphate as a precursor. The results proved the formation of spherical nanoparticles with an average particle size of about 23.24 nm, confirmed by scanning electron microscopy (SEM). The structural analysis demonstrated the existence of both tetragonal and monoclinic phases, with the dominance of the tetragonal phase. The photocatalytic evaluation under sunlight irradiation showed an impressive MB degradation efficiency of about 80 % in a relatively short time of 80 min. Thus, the study highlights the potential of ZrO2 NPs sensitized by a novel approach as highly efficient photocatalysis for water treatment.

Transformable self-delivered supramolecular nanomaterials combined with anti-PD-1 antibodies alleviate tumor immunosuppression to treat breast cancer with bone metastasis

Breast cancer is the most common malignant tumor that threatens women’s life and health, and metastasis often occurs in the advanced stage of breast cancer, leading to pathological bone destruction and seriously reducing patient quality of life. In this study, we coupled chlorin e6 (Ce6) with mono-(6-amino-6-deoxy)-beta-cyclodextrin (β-CD) to form Ce6-CD, and combined ferrocene with the FFVLG3C peptide and PEG chains to form the triblock molecule Fc-pep-PEG. In addition, the IDO-1 inhibitor NLG919 was loaded with Ce6-CD and Fc-pep-PEG to construct the supramolecular nanoparticle NLG919@Ce6-CD/Fc-pep-PEG (NLG919@CF). After laser irradiation, Ce6 produced robust reactive oxidative species to induce tumor cell apoptosis. Simultaneously, ferrocene became charged, and Fc-pep-PEG dissociated from the spherical nanoparticles, enabling their transformation into nanofibers, which increased both the retention effect and the induction of ferroptosis. The released NLG919 reduced the number of regulatory T cells (Tregs) and restored the function of cytotoxic T lymphocytes (CTLs) by inhibiting the activity of IDO-1. Moreover, combined administration with an anti-PD-1 antibody further relieved immune suppression in the tumor microenvironment. This article presents a new strategy for the clinical treatment of breast cancer with bone metastasis and osteolysis.Graphical

Robust TiN-based photothermal superhydrophobic coating with sandwich structure for effective anti−/de-icing applications

Photothermal superhydrophobic surfaces are prospective to become ideal anti−/de-icing surfaces because of their icing delay and rapid photothermal deicing property. Herein, a universal photothermal superhydrophobic composite coating (PSCC) was robustly sandwiched a photothermal layer based on hydrophobically modified titanium nitride (TiN) composite spherical nanoparticles (TiN@SiO2@OTES) between polydimethylsiloxane (PDMS) double layers (the top layer acting for protection and the bottom for thermal insulation and adhesion with the substrate). Due to the high photothermal conversion efficiency (66.0 %) of TiN nanoparticles, the composite coating demonstrated a satisfactory anti−/de-icing efficiency with a stable icing delay time (690 s at 1 sun and − 10 °C) and a fast photothermal de-icing capability (120 s under 1 sun and − 10 °C). In addition, the coating could maintain super-hydrophobicity exhibiting good durability and stability in the lash of sand and water due to the multi-layer design reinforced by PDMS, which was also favorable for residue-free removal of surface to achieve the self-cleaning. Overall, the robust corrosion-resistant photothermal superhydrophobic coating showed a potential for anti−/de-icing application.