AuNP Content Research Articles

Complex Formation of Gold Nanoparticles with Collagen in Aqueous Media Studied by X-ray Scattering and Absorption Spectroscopy.

Small-angle X-ray scattering and UV-vis absorption measurements were performed on mixed solutions of gold nanoparticles (AuNPs) and atelocollagen (AC), triple-helical collagen without telopeptide, in acetate buffer at pH 4 under different temperature conditions, i.e., preparation temperature Tprep and measurement temperature Tmeas. Due to the significantly higher electron density of gold than that of AC, the structure factor S(q) of AuNPs is readily estimated from the scattering intensities of AuNP-only and mixed solutions. The resulting S(q) profile for the mixed solution indicated significant attractive interactions, especially for the smaller AuNPs. Therefore, the sticky sphere model was applied to analyze S(q) to determine the interaction parameters at different Tprep and Tmeas. The attractive interactions between AuNPs were higher at higher Tprep, suggesting that single-chain AC tends to make the interactions between AuNPs more attractive than those for triple-helical AC. Complex formation was also detected by the aggregation-induced surface plasmon absorption shift. More densely packed AuNPs were detected from the absorption spectra for higher AuNP content at which the ζ potential disappeared, while a split absorption band was also found, indicating that not all AuNPs can form a complex with AC at ζ = 0.

Well-Ordered Nanoparticles/Block Copolymer Nanosheets with a Controllable Location of Nanoparticles.

Precisely controlling the spatial distributions and arrangements of metal nanoparticles (NPs) into block copolymers is of great importance for fabricating novel nanomaterials with the desired optical and electronic properties. Herein, we develop a simple yet versatile strategy to prepare organic/inorganic nanosheets formed by the coassembly of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and PS tethered gold nanoparticles (AuNPs@PS) within emulsion droplets. The arrangement of the AuNPs@PS building blocks within the block copolymers (BCP)/AuNPs nanosheets can be adjusted by tuning the effective size ratio (λeff), which can be controlled by the core diameter of the AuNPs and the molecular weight of the PS. Furthermore, the content of the AuNPs is also another essential parameter to manipulate the structures of the nanosheets with the specific λeff. Thus, the BCP/AuNPs hybrid nanosheets with controllable distributions and arrangements of the AuNPs were successfully prepared via tuning of λeff and the content of AuNPs. This study provides a facile way to fabricate well-ordered hybrid nanosheets.

Controllable Assemblies of Au NPs/P5A for Enhanced Catalytic Reduction of 4-Nitrophenol.

Efficient catalytic reduction of 4-nitrophenol (4-NP) is one focus of industry and practical engineering, because 4-NP is one of the most important sources of pollution of the ecological environment and human health. Here, coassembled hybrid composites of pillar[5]arene (P5A) and gold nanoparticles (Au NPs) were successfully developed by a one-step synthetic method as a type of water-insoluble catalyst for the reduction of 4-NP. The geometric and topological structures, as well as physiochemical properties of Au NPs/P5A composite catalyst, were fully characterized and analyzed through various tests such as transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), indicating that Au NPs were well dispersed on the surface of the two-dimensional film of assembled P5A. The influence factors of the catalytic reduction of 4-NP were further investigated and discussed, confirming that the content of Au NPs and the concentration of 4-NP were very significant during the catalysis. The catalytic reaction was carried out at the catalyst concentration of 100 mg·L-1 and an initial 4-NP concentration of 90 mg·L-1 under 30 °C. The calculated reaction rate constant was 0.3959 min-1 and the reduction rate of 4-NP was more than 95% in 20 min. In addition, the as-prepared catalyst can maintain a high catalytic efficiency after five cycles. Thus, the easily recyclable composite catalyst with poor aqueous solution can exhibit prospective application to the treatment of 4-NP in water.

Localize surface plasmon resonance of gold nanoparticles and their effect on the polyethylene oxide nanocomposite films

Colloidal Gold nanoparticles (AuNPs) with sodium citrate coating were successfully synthesized using a chemical reduction method with an average spherical size of about 20 nm dispersed in the water with high stability. The localized surface plasmon resonance (LSPR) peak was studied by experimental measurement and Mie theory. The absorbance spectrum of AuNPs exhibits a fingerprint peak in the 500–600 nm range, corresponding to the LSPR of AuNPs. Moreover, PEO/AuNPs nanocomposite films with different concentrations of AuNPs were also prepared to evaluate the effect of LSPR of AuNPs on the electrical conductivity and photoconductivity of nanocomposite films. The degree of crystallinity (Xcrys) and melting enthalpy (ΔHm) increase as the AuNPs content in the polymer matrix increases up to 0.5 wt% due to the enhanced nucleation points. The electrical conductivity of pure PEO film is 1.93×10−6 S.cm−1. Increasing the AuNPs concentration to 0.5 wt% in the PEO matrix leads to an increase in the electrical conductivity to 2.28×10−3 S.cm−1 as AuNPs.

Trametes versicolor laccase activity modulated by the interaction with gold nanoparticles

In this study, the impact of gold nanoparticles (AuNPs) on the structure and activity of laccase from Trametes versicolor (Lc) was described. Fluorescence experiments revealed that AuNPs efficiently quench Lc's tryptophan fluorescence by a static and dynamic process. By using differential scanning microcalorimetry and circular dichroism spectroscopy, it was determined how the concentration of nanoparticles and the composition of the medium affected the secondary structure of Lc. The data revealed that upon binding with AuNPs, conformational changes take place mainly in presence of high amounts of nanoparticles. The complex kinetic analysis unveiled the Lc activity enhancement at low concentrations of AuNPs as opposed to the concentrated regime, where it can be reduced by up to 55%. The Michaelis-Menten tests highlighted that the activity of the biocatalyst is closely related to the concentration of AuNPs, while the Selwyn analysis demonstrated that even in a concentrated regime of Lc it is not deactivated regardless of the amount of AuNPs added. The thermal parameters improved by twofold in the presence of low AuNPs concentration, whereas the activation energy increased with AuNPs content, implying that not all collisions are beneficial to the enzyme structure. The effect of AuNPs on the decomposition of a recalcitrant dye (naphthol green B, NG) by Lc was also evaluated, and the Michaelis-Menten model revealed that only the high AuNPs content influenced negatively the Lc activity. The isothermal titration calorimetry revealed that hydrogen bonds are the main intermolecular forces between Lc and AuNPs, while electrostatic interactions are responsible for NG adsorption to AuNPs. The results of the docking analysis show the binding of NG near the copper T1 site of Lc with hydrogen bonds, electrostatic and hydrophobic interactions. The findings of this work provide important knowledge for laccase-based bio-nanoconjugates and their use in the field of environmental remediation.

Constructing and electrochemical performance of AuNPs decorated MIL-53 (Fe, Ni) MOFs–derived nanostructures for highly sensitive hydrazine detection

A novel hydrazine electrochemical sensor with superior sensing capabilities was fabricated by using electrodepositing gold nanoparticles (AuNPs) on the surface of MIL-53 (Fe, Ni) MOFs–derived nanostructures on nickel foam (NF) supporter by solvothermal method. The crystal phase, morphology structure, surface elemental composition and chemical state of AuNPs decorated NiFe2O4/NF products were studied using different characteristic techniques. To improve the electrochemical performances, various parameters of the AuNPs@NiFe2O4/NF sensor were systematically optimized to encompass the reaction time, deposition content of Au NPs and PBS solution pH. Our results demonstrate that the as-fabricated electrochemical sensor based on Au90NPs@NiFe2O4/NF presents excellent electrochemical performances, which includes high sensitivity with 9220 μA·mM−1·cm−2, a wide linear range of 0.3–150 μM and within a low detection limit (LOD) of 0.05 μM, good selectivity as well as reliable stability and reproducibility. Meanwhile, it is feasible to apply the developed Au90NPs@NiFe2O4/NF sensor for highly sensitive hydrazine detection in the tap water with recoveries between 97.2 and 104.2%. The measured RSD is less than 2.77%, which exhibits high potential for the sensor’s practical applications.

Ingenious design of ternary hollow nanosphere with shell hierarchical tandem heterojunctions toward optimized Visible-light photocatalytic reduction of U(VI)

TiO2 based photocatalytic reduction has been regarded as a promising technology for flexibility of uranium recovery from seawater, however, the use of sacrificing agents and protection gas are two major challenges for practical application. Herein, a ternary hybrid TiO2@CdS@Au hollow nanosphere (TCA) was designed and synthesized for highly efficient photocatalytic reduction of U(VI). The designed ternary hollow nanosphere is composed of double heterojunctions: type-Z heterojunction generated between TiO2 with CdS and metal–semiconductor junction between CdS and Au NPs, which is contributive for the spatial separation and diffusion of photogenerated charges. Therefore, compared with loaded Pt or GOQDs, the superior photocatalytic reduction efficiency of TCA2 (Au NPs content of 0.8%) for U(VI) achieves 99.7% within 25 min and remains unchanged after five cycles in the presence of 3 mmol·L-1 NaHCO3 under air condition. Its photoreduction rate constant is 5.7 and 4.1 times as much as the CdS and hollow TiO2@CdS nanosphere. Additionally, in the absence of any protective gases and holes sacrificial agent, the soluble U(VI) adsorbed on the photocatalyst is reduced to insoluble α-U3O8 by photogenerated electrons and superoxide radical, which has been recognized as one of the most effective strategy for the separation and recovery U(VI) from polluted environment.

Analytical Performance and Validation of a Reliable Method Based on Graphite Furnace Atomic Absorption Spectrometry for the Determination of Gold Nanoparticles in Biological Tissues.

Gold nanoparticles (AuNPs) have a wide-ranging application and are widespread in samples with complex matrices; thus, efficient analytical procedures are necessary to identify and characterize this analyte. A sensitive analytical method for determination of AuNPs content in biological tissues, based on microwave-assisted acid wet digestion and graphite furnace atomic absorption spectrometry (GFAAS) validated in accordance with the requirements of Eurachem guideline and ISO 17025 standard, is presented in this study. The digestion procedure was optimized, and the figures of merit such as selectivity, limit of detection (0.43 µg L−1), limit of quantification (1.29 µg L−1, corresponding to 12.9 µg kg−1 in tissue sample, considering the digestion), working range, linearity, repeatability ((RSDr 4.15%), intermediate precision (RSDR 8.07%), recovery in accuracy study (97%), were methodically evaluated. The measurement uncertainty was assessed considering the main sources of uncertainties and the calculated relative expanded uncertainty (k = 2) was 12.5%. The method was applied for the determination of AuNPs in six biological tissues (liver, small intestine, heart, lungs, brain and kidneys) and the found concentrations were generally at low levels, close or lower than LOQ.

Construction of gold nanoparticles by tubular polysaccharide from black fungus and their apoptosis‐inducing activities in HepG2 cells

AbstractGold nanoparticles (AuNPs) with size of 12 ~ 25 nm were loaded on the dendritic nanotubes (DNTs), which were self‐assembled by the triple‐helix polysaccharides from black fungus (AF1). The characterization results proved that the AuNPs were dispersed on the surface of DNTs without affecting their tubular structure. Due to the dendritic structure, the loading content of AuNPs could arrived at 46.4%. Moreover, the potential anticancer activities of the complex (DNT‐Au) were evaluated by the induction of apoptosis in HepG2 cells. It was found DNT‐Au could be taken up by cells and enter into lysosomes, further inducing apoptosis in HepG2 cells by ROS‐mediated mitochondrial dysfunction. This work was benefit for the development of natural polysaccharide as a substrate to stabilize nanoparticles in biomedical fields.

Eco-Friendly Production of AuNPs and Their Impact on the Oil Oxidative Stability.

Vegetable oils have been used for different applications and, more recently, as an active host medium to obtain nanoparticles for employment in bionanotechnological applications. Nevertheless, oils are very susceptible to oxidation during production, storage, and transportation because of their chemical composition. Consequently, any modification in their production must be accompanied by an analysis of the oxidative stability. In this study, naked and biocompatible gold nanoparticles (AuNPs) were grown on sunflower oil during sputtering deposition using different deposition times. Size and morphology were determined by transmission electron microscopy (TEM) and their concentrations were found by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Rancimat® method was employed to evaluate the AuNPs influence on the oxidative stability of the vegetable oil. Well-dispersed quasi-spherical NPs were produced with a mean diameter in the 2.9–3.7 nm range and they were concentration-dependent on the deposition time. A concentration of about 11 mg/L, 38 mg/L, and 225 mg/L of AuNPs was obtained for a deposition time of 5 min, 15 min, and 30 min, respectively. The results also revealed that AuNPs negatively affected the oxidative stability of the sunflower oil and exponentially reduced the induction period (IP) with the increase in AuNPs content. IP reductions of 63%, 77%, and 81% were determined for the AuNPs containing samples at 11 mg/L, 38 mg/L, and 225 mg/L. For the first time, it is reported that naked AuNPs promote the rapid degradation of vegetable oil and this points out the need for attention relative to the quality of vegetable oils used to host metal nanoparticles.

Carboxymethyl cellulose supported green synthetic features of gold nanoparticles: Antioxidant, cell viability, and antibacterial effectiveness

Gold nanoparticles (AuNPs) are widely used in the diagnosis and treatment of diseases owing to their environmental friendliness and controllability due to their compatibility and high potency in drug delivery. Here, AuNPs were prepared from carboxymethyl cellulose (CMC) and showed an extensive absorption peak at 528 nm owing to the characterized Plasmon Surface Resonance. TEM measurement affirms that the Au particles had spherical shapes accompanied by a uniform distribution and a size of approximately 12-20 nm. Otherwise, SEM images showed that the AuNPs were configured in agglomerated spherical shapes and the crystalline phase was evident from SAED images and spikes in the XRD model. Vigorous antioxidant was tested using the DPPH scavenger analysis and the produced maximum trapping capacity (241.1 ± 13.22 mg/g) was reached at an AuNPs content of 106.25 mg/mL. The ratio of viable cells for AuNPs by HEK 293 T cell lines was reduced to 75.1 ± 3.8% at an approximated concentration of 500 μg / mL. Besides, the antibacterial potency was examined after one day of exposure to (E. coli and P. aeruginosa) and (S. aureus and B. subtilis). AuNPs were toxic against all selected bacteria. P. aeruginosa was the most susceptible bacterium to AuNPs with maximum inhibition zones of 50% whereas B. subtilis at 2 mg/L concentration of AuNPs takes the lowest percentages of inhibition zone with 30% compared to 25% for antibiotic standard. These extraordinary behaviors of AuNPs exhibits the manipulation of nanoparticles is highly recommended for universal use in the treatment of skin and wounds.

Tackling Complex Analytical Tasks: An ISO/TS-Based Validation Approach for Hydrodynamic Chromatography Single Particle Inductively Coupled Plasma Mass Spectrometry.

Nano-carrier systems such as liposomes have promising biomedical applications. Nevertheless, characterization of these complex samples is a challenging analytical task. In this study a coupled hydrodynamic chromatography-single particle-inductively coupled plasma mass spectrometry (HDC-spICP-MS) approach was validated based on the technical specification (TS) 19590:2017 of the international organization for standardization (ISO). The TS has been adapted to the hyphenated setup. The quality criteria (QC), e.g., linearity of the calibration, transport efficiency, were investigated. Furthermore, a cross calibration of the particle size was performed with values from dynamic light scattering (DLS) and transmission electron microscopy (TEM). Due to an additional Y-piece, an online-calibration routine was implemented. This approach allows the calibration of the ICP-MS during the dead time of the chromatography run, to reduce the required time and enhance the robustness of the results. The optimized method was tested with different gold nanoparticle (Au-NP) mixtures to investigate the characterization properties of HDC separations for samples with increasing complexity. Additionally, the technique was successfully applied to simultaneously determine both the hydrodynamic radius and the Au-NP content in liposomes. With the established hyphenated setup, it was possible to distinguish between different subpopulations with various NP loads and different hydrodynamic diameters inside the liposome carriers.

A Way to Predict Gold Nanoparticles/Polymer Hybrid Microgel Agglomeration Based on Rheological Studies.

In this work, a detailed rheological study of hybrid poly(acrylamide-co-acrylic acid) P(AAm-co-AAc) aqueous microgel dispersions is performed. Our intention is to understand how the presence of gold nanoparticles, AuNP, embedded within the microgel matrix, affects the viscoelastic properties, the colloidal gel structure formation, and the structure recovery after cessation of the deformation of the aqueous microgel dispersions. Frequency sweep experiments confirmed that hybrid microgel dispersions present a gel-like behavior and that the presence of AuNP content within microgel matrix contributes to the elasticity of the microgel dispersions. Strain sweep test confirmed that hybrid microgels aqueous dispersion also form colloidal gel structures that break upon deformation but that can be recovered when the deformation decreases. The fractal analysis performed to hybrid microgels, by applying Shih et al. and Wu and Morbidelli’s scaling theories, evidenced that AuNP significantly affects the colloidal gel structure configuration ending up with the formation of agglomerates or microgel clusters with closer structures in comparison to the reference P(AAm-co-AAc) aqueous microgel dispersions.

Preparation, structural analysis, morphological investigation and electrical properties of gold nanoparticles filled polyvinyl alcohol/carboxymethyl cellulose blend

Polymer nanocomposite samples have been prepared through the solution casting method utilizing a polymer blend of polyvinyl alcohol and carboxymethyl cellulose (70/30wt.%) as organic host matrix and different concentrations of biosynthesized gold nanoparticles (Au NPs) by the leaf extract of green mint (Mentha Spicata L.) as inorganic nanofiller. The structural, optical and morphological properties of these samples have been through FT-IR, XRD, UV/Vis. and SEM techniques. The FT-IR spectra confirm the blend components are miscible by the formation of Hydrogen bond interaction and show the polymer-nanoparticle interactions. The XRD analyses depict the semicrystalline structure of these samples and the crystallinity degree decrease with increase of Au NPs content within the PVA/CMC structure. The TEM micrograph of biosynthesized Au NPs indicates that shapes of these NPs are spherical NPs and triangular/hexagonal nanoplates with average size range 5–29nm. The alternating electrical conductivity, electrical impedance, complex dielectric permittivity and electric modulus spectra of prepared samples have been investigated at 25°C in the frequency range (0.1Hz–20MHz). Thus, the variations in values of conductivity, dielectric permittivity and relaxation times indicate the feasibility of these materials as flexible nanodielectric of frequency tunable permittivity for radio/audio frequency operating microelectronic/conventional devices.

Smart colloids containing ensembles of gold nanoparticles conjugated with κ-carrageenan

We study colloids of nanobiocomposites (NBC) containing Au nanoparticles (NP) obtained by reduction of gold precursor with functional groups of κCAR. The AuNPs content was changed from 2.0 to 5.6 w/w %. Hydrolysis of κCAR during reduction of gold ions produced carboxylate groups supporting nanobioconjugation (FT-IR data) and electrostatic stabilization through increased negative ζ-potential. The self-assembly of AuNPs took place after storing NBC, as shown by UV/vis. extinction and transmission electron microscopy. Analysis of the structure-sensitive Rg/Rh ratios obtained by dynamic and static light scattering showed that the colloids have core-shell structure. The macromolecules in the shell exhibited polyelectrolyte expansion at [NaCl] and [KCl] < 0.02 M. Above 0.02 M, the difference between non-specific sodium and specific potassium ions on the shell thickness was registered. The temperature hysteresis of the hydrodynamic radius Rh was similar to that of the pristine κCAR observed previously by optical rotation. Monitoring the equilibration of light scattering intensity at each mini-quenching step of the cooling run allowed further insight into the hysteresis origin. These colloids are interesting for sensing applications because of enhanced scattering of plasmonically coupled AuNPE. Their thermo- and ion-sensitivity can be useful in drug delivery.

Green synthesis of gold nanoparticles and its effect on the optical, thermal and electrical properties of carboxymethyl cellulose

Green synthesis is an innovative method to approach the synthesis of metallic nanoparticles employing eco-friendly substances acting as reducing agents. Solanum nigrum, Ricinus communis and Morus nigra were used separately for green synthesis of gold nanoparticles (AuNPs). Formations of AuNPs were approved from the surface plasmon resonance band in the Ultraviolet–visible (UV/Vis.) spectrum. Transmission electron microscope (TEM) micrograph exhibited that synthesized AuNPs have different shapes and sizes. After that AuNPs, which synthesized via Ricinus communis extract, was added with different doping level for Modified carboxymethylcellulose (CMC) for preparing polymeric films using the casting method. The XRD spectra of pure CMC exhibit hump centered at 2θ ≈ 21.5°, this hump intensity was decreased without a change in the position after addition the AuNPs to the CMC polymer. Optical energy gap (Eg) decreased with increasing content of AuNPs. The DC electrical conductivity (σ) measurements showed enhanced the electrical properties after added the AuNPs. These results denote the present samples can be used for photoelectric devices.

Influence of green synthesized gold nanoparticles on the structural, optical, electrical and dielectric properties of (PVP/SA) blend

Green synthesized gold nanoparticles with size 8–27 nm have been added to Polyvinyl pyrrolidone/Sodium alginate (PVP/SA) (50/50 wt%) blend by the casting technique. X-ray diffraction exposed the amorphous nature of the polymer blend (PVP/SA) and filled samples. The amorphous region increases with increasing Au NPs content. Fourier transform infrared spectra were achieved to illustrate the change in structure of the samples according to the filling manner. Ultraviolet/visible analysis was used to study the effect of adding Au NPs on the optical properties and used to calculate the energy gap (Eg) of (PVP/SA) composites. The values of optical energy gap (Eg) are reduced from 5.18 eV for blend to 3.52 for the nanocomposite film in the direct transition. Upon the addition of Au NPs, An enhancement for the conductivity, dielectric permittivity (ε′) and dielectric loss (ɛ") of (PVP/SA) are detected. The value of the activation energy (Ea) of the dielectric relaxation is calculated and is found to be 0.18 eV. Morphological properties were studied using scanning electron microscopy. SEM revealed the partial compatibility between the polymer blend (PVP/SA) and the Au NPs. Transmission electron microscopy image exhibited the cubic shape for gold nanoparticles with an average size 10–15 nm. Finally, Nano composites films can be used in several applications such as optical and optoelectronic devices.

Gold Nanoparticle Uptake in Tumor Cells: Quantification and Size Distribution by sp-ICPMS

Gold nanoparticles (AuNPs) are increasingly studied for cancer treatment purposes, as they can potentially improve both control and efficiency of the treatment. Intensive research is conducted in vitro on rodent and human cell lines to objectify the gain of combining AuNPs with cancer treatment and to understand their mechanisms of action. However, using nanoparticles in such studies requires thorough knowledge of their cellular uptake. In this study, we optimized single particle ICPMS (sp-ICPMS) analysis to qualify and quantify intracellular AuNP content after exposure of in vitro human breast cancer cell lines. To this aim, cells were treated with an alkaline digestion method with 5% TMAH, allowing the detection of gold with a yield of 97% on average. Results showed that under our experimental conditions, the AuNP size distribution appeared to be unchanged after internalization and that the uptake of particles depended on the cell line and on the exposure duration. Finally, the comparison of the particle numbers per cell with the estimates based on the gold masses showed excellent agreement, confirming the validity of the sp-ICPMS particle measurements in such complex samples.

Study on the organ distribution of gold nanoparticles synthesized by γ-irradiation using carboxymethyl chitosan stabilizer after intravenous administration in mice

Gold nanoparticles (AuNPs) with an average particle size of about 7 nm and concentration of 1 mM were synthesized by gamma rays irradiation method using 0.5% carboxymethyl chitosan (CMC) as a stabilizer. The characteristics of AuNPs were verified using UV-vis spectrum and TEM (Transmission Electron Microscope) images. The synthesized AuNPs were intravenously injected into tail of mice with a dose of 1 mg AuNPs per mouse for investigation of the in vivo distribution of AuNPs at different times. The analytical results showed that there was no significant difference in the blood haematological and serum biochemical indexes between the mice administrated with AuNPs and the control group. The gold content in the samples determined by k0-neutron activation analysis (k0-NAA) method indicated that after injection 1 h, AuNPs were mainly accumulated in liver (64.92%), blood (31.33%) and a small amount in lungs (2.16%) and kidneys (1.60%). After 6 hrs post-injection, the content of AuNPs was almost not determined in the blood, but its accumulation was increased in livers with 88.85%, lungs with 8.55% and kidneys with 2.10%. After 12 hrs of intravenous administration, the content of AuNPs was found to be slightly reduced by 83.86% in liver, but it was almost unchanged in lungs and kidneys. The results obtained in this study clearly indicated the distribution and the retention time of AuNPs in the mice. The AuNPs synthetized by gamma rays irradiation may potentially be developed for application as an X-ray contrast agent in diagnosis and as antioxidant agent for liver protection.

Structural, thermal and electrical studies of polyethylene oxide/starch blend containing green synthesized gold nanoparticles

The green synthesis of nanoparticles has become a matter of great interest in recent times and proposed as an environmentally friendly alternative to chemical and physical methods. Blend of polyethylene oxide (PEO)/starch (70/30 wt%) doped with various concentrations of gold nanoparticles (Au NPs) were prepared by casting technique. X-ray diffraction (XRD) shows the semi-crystalline nature of all prepared samples. It also shows an increase in the amorphous region due to raising the doping level. Fourier Transform Infrared (FT-IR) spectra showed a change in intensities of OH groups and CH2 asymmetric stretching vibration after addition of gold nanoparticles, these changes were attributed to the interaction between polymeric matrix and Au NPs. Scanning electron microscopy (SEM) exhibited the partial compatibility between the polymer blend and the Au NPs. Differential scanning calorimetry (DSC) measurement indicated miscibility between the two polymers. The electrical properties were investigated via DC electrical conductivity, where found electrical conductivity increased as Au NPs content increased. The results suggest the choice of Au NPs as filler to enhance the electrical, optical, and thermal properties of PEO/starch blend.