Instantaneous phytosynthesis of gold nanoparticles via Persicaria salicifolia leaf extract,and their medical applications

In the current investigation, an instantaneous, single step, cost-effective, and environmentally safe biosynthesis of gold nanoparticles (AuNPs) using the aqueous extract of P. salicifolia leaves is reported for the first time. P. salicifolia-AuNPs were characterized via several techniques including UV–Visible spectroscopy, Zeta potential, Fourier Transform Infrared (FT-IR) spectroscopy, Energy Dispersive X-ray spectroscopy (EDX) attached to SEM, High-resolution Transmission electron microscope (HRTEM), X-ray diffraction (XRD), and Selected Area Electron Diffraction (SAED), EDX elemental mapping and X-ray Photoelectron Spectroscopy (XPS). Results demonstrated the formation of violet-colored, mostly spherical-shaped AuNPs with a diameter between 5 and 23 nm and a plasmon peak at 535 nm indicated the successful phytosynthesis of AuNPs using the aqueous extract of the investigated species. The cytotoxicity investigation of the phytosynthesized AuNPs using Sulphorhodamine-B (SRB) assay reflected superb cell capability in inhibiting the growth and proliferation of human breast cancer cells (MCF7 cell line) with IC₅₀ 2.24 μg/mL. Additionally, P. salicifolia-AuNPs were proved to be a potent antioxidant. These results offer a promising route of AuNPs synthesis using the extract of P. salicifolia.     

Assessment of in‐vivo biocompatibility evaluation of phytogenic gold nanoparticles on Wistar albino male rats

Nanomedicine is an interdisciplinary approach that involves toxicology and other medicinal applications. Gold nanoparticles (AuNPs) may serve as a promising model to address the size and shape‐dependent biological response because they show good biocompatibility. This study is to prepare phytosynthesis AuNPs from ten different Cassia sp. Among them, the aqueous leaf extract of C. roxburghii produced greater efficient and stable AuNPs. The AuNPs were optimised for different physicochemical conditions. Highly stable AuNPs were synthesised at pH 7.0, 37°C, 1.0 ml of C. roxburghii leaf extract and 1.0 mM concentration of HAuCl₄ with the particle size of ∼50 nm and these AuNPs were stable up to 12 months. To determine the safety profile of AuNPs in‐vivo, the nanoparticles were injected intravenously into male Wistar albino rats in varying dosages. The authors noticed no significant difference in body weights, haematological and biochemical parameters and the histopathological sections of all vital organs. Highest accumulation was seen in spleen and least in brain. The authors’ results show that the AuNPs were biocompatible and did not produce any adverse or abnormalities in‐vivo. The implications of the bioaccumulation of AuNPs need to be further studied to rule out any adverse effects on long‐term exposure.Inspec keywords: blood, nanoparticles, cellular biophysics, pH, nanomedicine, particle size, nanofabrication, gold, biomedical materialsOther keywords: in‐vivo biocompatibility evaluation, phytogenic gold nanoparticles, phytosynthesis AuNPs, physicochemical conditions, Wistar albino male rats, nanomedicine, Cassia sp., aqueous leaf extract, C. roxburghii leaf extract, particle size, bioaccumulation, temperature 37.0 degC, Au     

Gold nanoparticles loaded into niosomes: A novel approach for enhanced antitumor activity against human ovarian cancer

In the current study, gold nanoparticles (AuNPs) were prepared using the green synthesis method using Artemisia annua extract, loaded into niosomes, and investigated their cytotoxicity and apoptotic effects. To optimize the niosomal formulation containing AuNPs, the effects of surfactants: cholesterol molar ratio, Span 60: Tween 60 M ratio, and AuNP concentration (µg/mL) were investigated. After examining the drug release profile, mathematical models were assessed to predict release kinetic. The cytotoxicity of noisome encapsulated AuNPs and free AuNPs was evaluated against human ovarian cancer cell line (A2780) by MTT assay. The apoptotic/necrosis ratio was studied using flow cytometry as well as Real-Time PCR was used for the Bax and Bcl-2 apoptosis gene expression. The results showed that the entrapment efficiency and particle size of optimized niosomal formulation encapsulated AuNPs were 34.49%±0.84 and 153.6 ± 4.62 nm with a regular spherical shape, respectively. The release profile of AuNPs from niosomal formulation was 59%±1.0 after 8 h suggesting the controlled release profile. This formulation exerted dose-dependent cytotoxicity against the A2780 cells via induction of apoptosis and significant upregulation of mRNA expression of Bax gene; while expression of anti-apoptotic gene Bcl-2 was down-regulated. Thus, the findings suggest that AuNP-loaded niosomal formulation is considered a promising and suitable targeted system for improving anti-tumor activity against A2780 cells.     

A composite prepared from covalent organic framework and gold nanoparticles for the electrochemical determination of enrofloxacin

A high conductivity composite based on covalent organic frameworks/gold nanoparticles (TAPB-PDA-COFs/AuNPs, TAPB: 3,5-tris(4-aminophenyl)benzene, PDA: p-phthalaldehyde) was prepared by a simple in-situ synthesized method and a novel electrochemical sensor based on TAPB-PDA-COFs/AuNPs was constructed for detection of Enrofloxacin (ENR). A variety of different characterization techniques including ultraviolet‐visible spectrophotometer (UV–vis), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the TAPB-PDA-COFs/AuNPs. ENR was detected by square wave stripping voltammetry (SWV) according to the relationship between the ENR concentration and the oxidation peak current. The result showed that TAPB-PDA-COFs/AuNPs was synthesized successfully. The electrochemical sensor showed two linear ranges in the range of 0.05–10 μmol L^?1 and 10–120 μmol L^?1 with the limit of detection of 0.041 μmol L^?1 (S/N = 3). The good recoveries (96.7–102.2%) and low RSDs (0.9–6.4%) indicated the possibility of using this sensor for actual sample detection. Therefore, TAPB-PDA-COFs/AuNPs-based electrochemical sensor showed good performance in detecting ENR, and would be a potential candidate for the development of fluoroquinolones determination.     

Green synthesized silver nanoparticle from Allium ampeloprasum aqueous extract: Characterization,antioxidant activities,antibacterial and cytotoxicity effects

In the current study for the first time, silver nanoparticles (AgNPs) were biosynthesized by reducing agents from hot water extract of Allium ampeloprasum, an antibacterial and anti-inflammatory edible plant. UV–vis. spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, X-ray diffractometric, and transmission electron microscopy (TEM) analyses have been applied to confirm the formation of biosynthesized AgNPs. Total phenol content and antioxidant activities of AgNPs and extract together with their antibacterial and cytotoxic properties, were evaluated. According to TEM, AgNPs were spherical with a diameter of 8–50 nm. Total phenolic compounds were 15.58 μg/mL, and 10.94 μg/mL at a concentration of 150 μg/mL for the A. ampeloprasum extract and the biosynthesized AgNPs, respectively. Biosynthesized AgNPs showed significant antioxidant activity (81%) as compared to A. ampeloprasum extract (32%) and were active on multi-drug resistant P. aeruginosa. Besides, the cytotoxic activity response was also demonstrated that AgNPs were more potent than the A. ampeloprasum extract and showed high activity against Hela cell line with an IC₅₀ value of less than 25 µg/mL. In conclusion, AgNPs synthesized by A. ampeloprasum extract with excellent antioxidant and antibacterial effects and acceptable cytotoxicity on cervical cancer cells have the potential to be used in biological applications.     

Inhibiting Au nanoparticle aggregation in freeze-thawing by presence of various additives

After freezing aqueous suspensions of gold nanoparticles (AuNPs) in the presence of various substances, the resulting aggregation of the nanoparticles was evaluated and the anti-aggregation effects of the different additives were compared. Many of the additives exhibited an anti-aggregation effects during freeze-thawing, the extent of which was greater at higher additive concentrations and the effects were 5 ~ 35% less than during the actual freeze-drying. Dextran and polyvinylpyrrolidone highly inhibited the aggregation even at markedly low additive concentrations (2 µg/mL). The use of a combination of a disaccharide (2 mg/mL of sucrose) and a sugar ester (20 µg/mL of sucrose palmitate) successfully preserved the redispersibility of the product after freeze-thawing while using each separately did not. Regarding the influence freezing and thawing conditions, a higher thawing temperature (from 4˚C to 60˚C) resulted in 10 ~ 20% better redispersibility of the AuNPs whereas the freezing temperature had no significant affect. The effect of freezing/thawing cycles of suspensions of AuNPs was also examined. The concentration of additive molecules on the surfaces of the frozen particles was monitored by In-situ Fourier transform IR spectroscopy. The collective findings of this study indicate that the additives essentially exert an anti-aggregation effect by slowing down the movement of the AuNPs.     

Green synthesis of silver oxide nanoparticles using Panicum miliaceum grains extract for biological applications

In this report, the silver oxide nanoparticles were green synthesized using Panicum miliaceum grains extract and were proposed for the first time. GC–MS analysis explicated 2-Acetylbenzoic acid was the active phytocompound with 97.07% of presence in aqueous grains extract. The synthesized silver oxide nanoparticles were analyzed by several analytical techniques such as UV–visible, XRD, FT-IR, HR-TEM, TG, XPS, EDX and mapping analyses. The results of various analytical techniques confirmed the silver oxide nanoparticles formation. The formed nanoparticles were in 10–25 nm size. The effectual bioactive properties of nanoparticles were revealed through antioxidant, anti-diabetic, anti-inflammatory, larvicidal and insecticidal activities. The high mortality of larvae and insect was observed at 48 h in 100 ppm and 72 h in 100 μg/Kg concentration, respectively. The antibacterial activity explained the bactericidal property of nanoparticles on S. aureus and S. typhi at 150 μg/mL concentration. The effective drug activity of nanoparticles was observed from 98.10 % of toxicity against A549 lung cancer cells at 100 μg/mL concentration. The growth of Vigna unguiculata was efficiently increased by lower concentration (60 ppm) of nanoparticles. According to results, the green synthesized nanoparticles can be applied in pharmaceutical and agricultural sectors as biocompatible, non-toxic and cost-effective material.     

Temperature-dependent spectroscopy and microchip laser operation of Nd:KGd(WO4)2

High-resolution absorption and stimulated-emission cross-section spectra are presented for monoclinic Nd:KGd(WO₄)₂ (Nd:KGW) laser crystals in the temperature range 77–450 K. At room-temperature, the maximum stimulated emission cross-section is σ_SE = 21.4 × 10⁻²⁰ cm² at 1067.3 nm, for light polarization E || N_m. The lifetime of the ⁴F_3/2 state of Nd³⁺ in KGW is practically temperature independent at 115 ± 5 μs. Measurement of the energy transfer upconversion parameter for a 3 at.% Nd:KGW crystal proved that this was significantly smaller than for alternative hosts, ∼2.5 × 10⁻¹⁷ cm³/s. When cut along the N_g optical indicatrix axis, the Nd:KGW crystal was configured as a microchip laser, generating ∼4 W of continuous-wave output at 1067 nm with a slope efficiency of 61% under diode-pumping. Using a highly-doped (10 at.%) Nd:KGW crystal, the slope efficiency reached 71% and 74% when pumped with a laser diode and a Ti:Sapphire laser, respectively. The concept of an ultrathin (250 μm) Nd:KGW microchip laser sandwiched between two synthetic diamond heat-spreaders is demonstrated.     

Growth and characterization of (Pb,La)TiO3 films with and without a special buffer layer prepared by RF magnetron sputtering

The (Pb, La)TiO₃ (PLT) ferroelectric thin films with and without a special buffer layer of PbO_x have been deposited on Pt/Ti/SiO₂/Si(100) substrates by RF magnetron sputtering technique at room temperature. The microstructure and the surface morphology of the films annealed at 600 °C for 1 h have been investigated by X-ray diffraction (XRD) and atomic force microscope (AFM). The surface roughness of the PLT thin film with a special buffer layer was 4.45 nm (5 μm × 5 μm) in comparison to that of 31.6 nm (5 μm × 5 μm) of the PLT thin film without a special buffer layer. Ferroelectric properties such as polarization hysteresis loop (P–V loop) and capacitance–voltage curve (C–V curve) of the films were investigated. The remanent polarization (P_r) and the coercive field (E_c) are 21 μC/cm² and 130 kV/cm respectively, and the pyroelectric coefficient is 2.75 × 10^− 8 C/cm² K for the PLT film with a special buffer layer. The results indicate that the (Pb, La)TiO₃ ferroelectric thin films with excellent ferroelectric properties can be deposited by RF magnetron sputtering with a special buffer layer.     

Magnetite nanoparticles with high heating efficiencies for application in the hyperthermia of cancer

Magnetic hyperthermia is a safe method for cancer therapy. A gap-type alternating current magnetic field (100 kHz, 100–300 Oe) is expected to be clinically applicable for magnetic hyperthermia. In this study, magnetite nanoparticles (MNPs) varying in size from 8 to 413 nm were synthesized using a chemical coprecipitation and an oxidation precipitation method to find the optimum particle size that shows a high heating efficiency in an applied magnetic field. The particles' in vitro heating efficiency in an agar phantom at an MNP concentration of 58 mg Fe/ml was measured in an applied magnetic field. In a magnetic field of 120 Oe, the temperature increase (ΔT) of the agar phantom within 30 s was 9.3 °C for MNPs with a size of 8 nm, but was less for the other samples, while in a magnetic field of 300 Oe, ΔT = 55 °C for MNPs with a size of 24 nm, and ΔT = 25 °C for MNPs with a size of 8 nm. The excellent heating efficiency of MNPs with a size of 24 nm in a magnetic field of 300 Oe may be due to a combination of the effects of both relaxation and hysteresis losses of the magnetic particles. It is believed that MNPs with a size of 8–24 nm will be useful for the in situ hyperthermia treatment of cancer.     

Low temperature growth of SnO2 nanowires by electron beam evaporation and their application in UV light detection

For the first time, high quality tin oxide (SnO₂) nanowires have been synthesized at a low substrate temperature of 450 °C via vapor–liquid–solid mechanism using an electron beam evaporation technique. The grown nanowires have shown length of 2–4 μm and diameter of 20–60 nm. High resolution transmission electron microscope studies on the grown nanowires have shown the single crystalline nature of the SnO₂ nanowires. We investigated the effect of growth temperature and oxygen partial pressure on SnO₂ nanowires growth. Variation of substrate temperature at a constant oxygen partial pressure of 4 × 10⁻⁴ mbar suggested that a temperature equal to or greater than 450 °C was the best condition for phase pure SnO₂ nanowires growth. The SnO₂ nanowires grown on a SiO₂ substrate were subjected to UV photo detection. The responsivity and quantum efficiency of SnO₂ NWs photo detector (at 10V applied bias) was 12 A/W and 45, respectively, for 12 μW/cm² UV lamp (330 nm) intensity on the photo detector..     

Impedance spectroscopy characterization of relaxation mechanisms in gold–chitosan nanocomposites

Au–Chi nanocomposites with different AuNPs additions were investigated. The dispersion of AuNPs in polymer matrix was observed using s-SNOM analysis. The dielectric properties as a function of temperature show two relaxation processes: (1) a primary α-relaxation process, at low temperatures; (2) a second low frequency relaxation at temperatures between 70 °C and 150 °C identified as the σ-relaxation often associated with short range ion mobility. In nanocomposite films, the σ-relaxation process overcomes the α-relaxation process so that the glass transition is no longer detected. The dielectric nonlinear properties (tunability) shown an increase of dipolar moment with AuNPs additions and this results are in good correlation with matrix modification in FTIR investigation.     

Interplay between random laser performance and self-frequency conversions in NdxY1.00−xAl3(BO3)4 nanocrystals powders

Random Laser emission at 1.06 μm, self-second-harmonic generation at 0.53 μm and self-sum-frequency generation at 0.46 μm were investigated in Nd_xY_1.00−xAl₃(BO₃)₄ nanocrystalline powders, for 0.05 ⩽ x ⩽ 1.00, excited by a pulsed laser operating at 808 nm, focusing on the interplay between the RL performance and the second-order nonlinear processes. The RL performance, characterized by a figure-of-merit relating the laser slope efficiency and the excitation pulse energy threshold, improved as x increased up to 1.00 while the efficiency of the self-frequency conversion processes reduced for increasing x because of distortions introduced in the crystalline structure of the grains. The RL wavelength was also dependent on the Nd³⁺ concentration and presented a redshift from 1061.9 nm to 1063.5 nm for increasing values of x.     

Improved performances in a top-emitting green organic light-emitting device with light magnification

A top-emitting organic light-emitting device (TOLED) with an architecture of Si/SiO₂/Ag (100 nm)/Ag₂O (UV ozone treatment for 30 s)/ 4′,4?-tris(3-methylphenylphenylamino)triphenylamine (45 nm)/4,4′-bis [N-(1-naphthyl-1-)-N-phenyl-amino]-biphenyl (5 nm)/tris-(8-hydroxyquinoline) aluminum (Alq₃):10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-benzo[l]-pyrano[6,7,8-ij]quinolizin-11-one (C545T) (1: 0.5 weight %, 20 nm)/Alq₃ (30 nm)/LiF(1 nm)/Al (0.5 nm)/Ag(30 nm) is designed with a resonance wavelength in the TOLED corresponding to the peak wavelength of C545T. With this enhanced cavity structure, light magnification with a coefficient of ∼ 19 (forward direction) is observed, leading to significantly improved performances with brightness of 80215 cd/m² at 9 V, luminous efficiency of 32.7 cd/A at 6 V, external quantum efficiency of 8.9% at 7.5 V, and low turn-on voltage of 2.5 V.     

Anti-amyloidogenic activity of glutathione-covered gold nanoparticles

This study is an investigation of the effect of biocompatible glutathione-covered gold nanoparticles (AuSG_7) with an average size of 3 nm on the amyloid fibrils of hen egg-white lysozyme. The anti-amyloid activity of AuSG_7 nanoparticles on this protein was monitored with thioflavin T assay, atomic force microscopy and transmission electron microscopy. The study found that AuSG_7 nanoparticles in vitro depolymerize the amyloid aggregates and inhibit lysozyme aggregate formation. The ability to inhibit amyloid formation and promote amyloid disassembly has concentration-dependent characteristics: the concentration of nanoparticles at which inhibition is half maximal (IC₅₀) was found to be 6.19 μg/mL, and the concentration at which depolymerization is half maximal (DC₅₀) was found to be 8.26 μg/mL.     

Comparative study between Phragmites australis root and rhizome extracts for mediating gold nanoparticles synthesis and their medical and environmental applications

In this research, we adopt an ecofriendly and sustainable approach to compare the potentiality and efficiency of Phragmites australis aqueous extracts of two different organs to fabricate gold nanoparticles (AuNPs). The aqueous extracts of plant roots and rhizome were used as alternative reducing agents to conventional chemicals. Various Characterization techniques were used; UV–Vis spectroscopy, Zeta potential, Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Selected Area Electron Diffraction (SAED), Energy Dispersive X-ray Spectroscopy (EDX), High Resolution Transmission Electron Microscopy (HRTEM) equipped with elemental mapping in order to confirm the formation of zero-valent AuNPs, X-ray photoelectron spectroscopy (XPS). Our results demonstrated that both extracts of Phragmites australis are good candidates for the green-synthesis of AuNPs. Zeta potential was used to confirm the stability of AuNPs. The cytotoxic capacities of both AuNPs samples were validated using MTT assay which proved the inhibition of the growth and proliferation of human lung cancer cells (A549 cell line). Antioxidant potentialities were >10%. The phytosynthesized AuNPs exhibited high capacity in removing methylene blue and methyl orange dyes within just one min. This research offers an alternative solution to manage the accumulated unwanted biomass of a widely distributed aquatic macrophyte in aquatic ecosystems.     

DNA-lipid-apatite composite layers enhance gene expression of mesenchymal stem cells

DNA-apatite composite layer (D-Ap layer) and DNA-lipid-apatite composite layer (DLp-Ap layer) were prepared on ceramic hydroxyapatite disk and scaffold using supersaturated calcium phosphate solutions supplemented with 0.5–5 μg/mL plasmid and 0–10 μL/mL lipid transfection reagent FuGENE®. Both in vitro and in vivo studies were carried out using mesenchymal stem cells (MSCs) and two kinds of gene (luciferase and bone morphogenetic protein (BMP)-2) for demonstrating potential application of the gene transfer system using the D-Ap and DLp-Ap layers in bone tissue engineering. In the in vitro study using luciferase gene, the DLp-Ap layers showed 1–2 orders of magnitudes higher gene transfer efficiency to MSCs than the D-Ap layer. In the in vivo study using BMP-2 gene, DLp-Ap layer slightly increased BMP-2 protein concentration than D-Ap layer, thereby enhancing their osteogenic differentiation than D-Ap layer. The present gene transfer system using the DLp-Ap layers, with the advantages of good biocompatibility, bone-bonding ability, and efficacy in in vitro and in vivo gene transfer to MSCs, would be useful in bone tissue engineering.     

Preparation of gold/hydroxyapatite hybrids using natural fish scale template and their effective albumin interactions

The gold (Au) nanoparticles (NPs) with the diameter of 15–40?nm were successfully synthesized in the hierarchical hydroxyapatite (HAp) nanostructures of natural fish scale templates, which were carried out by the Au³⁺ ion chemisorption, reduction and calcination processes to form the AuNPs/HAp hybrids. The AuNPs size as well as the surface plasmon resonance (SPR) absorption maximum was preserved with the hybridization process. Moreover, the AuNPs/HAp hybrid nanostructures exhibited preferential protein adsorption behavior at the biological bovine serum albumin (Ab) concentration regions that correspond to be 1.5?μM in the cell culture medium and 15.1?μM in human blood, and the Ab adsorption equilibrium constant of AuNPs/HAp hybrid was higher than that of the HAp alone. The SPR absorption maxima of the Ab-adsorbed AuNPs/HAp fish scales were red-shifted as compared with those of the AuNPs/HAp fish scales. Therefore, we synthesized the AuNPs using the fish scale template to exhibit the preferential protein adsorption, which will be a great significance to research the AuNPs/HAp hybrid functions.     

Comparisons of phase morphology and physical properties of PVDF nanocomposites filled with organoclay and/or multi-walled carbon nanotubes

Binary and ternary poly(vinylidene fluoride) (PVDF) nanocomposites filled with organoclay (15A) and/or multi-walled carbon nanotubes (MWNTs) were successfully prepared. MWNTs were dispersed more homogeneously than 15A within PVDF matrix, and the presence of MWNTs facilitated the dispersibility of 15A. The 15A addition induced β-form PVDF crystal formation, but MWNTs hardly changed the α-form crystal development. Both nanofillers facilitated the nucleation of PVDF (up to 12.3 °C increase), and the efficiency of enhancing PVDF crystallization followed the sequence MWNT > 15A/MWNT > 15A. The nanocomposites possess higher T_m° than neat PVDF. In particular, adding 15A led to a T_m° (β-form) increase of no less than 11 °C. A rheological percolation threshold at 1 wt.% MWNT loading was determined. The electrical resistivity dropped by more than 13 orders of magnitude at 5 wt.% MWNT loading. The nanocomposites exhibited enhanced tensile modulus (up to 83% increase with MWNTs inclusion) compared with neat PVDF.     

Hardness enhancement and oxidation resistance of nanocrystalline TiN/MoxC multilayer films

In this paper the influence of the layer's microstructure on the hardness enhancement in multilayer nanocrystalline films and the oxidation resistance are studied. The TiN/Mo_xC multilayer films at different modulation period, and Mo_xC and TiN monolayer films were deposited on the (0 0 1) silicon wafers and molybdenum sheets by rf and dc magnetron sputtering. The monolayer TiN films with a thickness of about 2 μm are of pure face-center cubic TiN phase, while the monolayer Mo_xC films consist of two phases, one of which is body-center cubic Mo and the other is hexagonal Mo₂C as determined by XRD. The coarse columnar grains of about 200 nm in the monolayer TiN films become much smaller or disappear in the multilayer films. The hardness enhancement of the multilayer films takes place at the modulation period of 320 nm, which can reach to 26 GPa and is much higher than the values of Mo_xC and TiN monolayer films. This enhancement in hardness can be explained as the decrease in the size and/or disappearance of columnar grains in the TiN layer. The Young's modulus in the temperature range from 100 to 400 °C increases with decreasing modulation period. It is found that about 100 nm thick TiN films can increase largely the oxidation resistance of Mo_xC films.