Incorporation Of AuNPs Research Articles

Poly(N-isopropylacrylamide)-chitosan nanogels for nanotechnological and catalytic applications

Polymer nanogels consisting of poly(N-isopropylacrylamide) and chitosan [P(NC)] were synthesized using a free radical precipitation polymerization technique in an aqueous environment. This process involved the polymerization of N-isopropylacrylamide (NIPAAM) with chitosan (CS) and a cross-linker. These P(NC) nanogels were utilized as nano-reactors for the synthesis of gold nanoparticles (AuNPs), which were formed within the polymeric network through an in-situ reduction process using chloroauric acid [H(AuCl4)] as precursor salt and sodium borohydride (NaBH4) as the reductant. Various analytical methods, including transmission electron microscopy (TEM), Thermogravimetric analysis (TGA), ultraviolet–visible spectroscopy (UV–Vis), and Fourier transform infrared spectroscopy (FTIR), were employed to confirm the formation of P(NC) nanogels and the incorporation and durability of AuNPs within the P(NC) nanogels. The AuNPs loaded P(NC) nanogels were utilized as catalysts for the reduction of 4-nitrophenol (4-NiP) into 4-aminophenol (4-AmP) in the presence of NaBH4. This system was also used to degrade a number of dyes including methylene blue (MB), methylene orange (MO), Rhodamine B (RhB), brilliant blue (BB) and eosin Y ((EY) by using NaBH4 as reducing agent. The Au-P(NC) catalyst exhibited remarkable efficiency, facilitating the fast reduction of 4-NiP and degradation of dyes within a very short interval of time. This system stands out for its economic usage, as even a small quantity of it can efficiently reduce toxic pollutants like 4-NiP and dyes. The results of the reactions highlighted exceptional yield, emphasizing the effectiveness and recyclability of the Au-P(NC) hybrid nanogels as highly capable catalysts.

Plasmonic sensing platform for C-reactive protein recognition via synthetic receptors decorated on graphene oxide and gold nanoparticles

C-reactive protein (CRP) level provides important information about the health status of the individual in predicting many diseases such as cardiovascular, chronic inflammatory, and neurodegenerative diseases. Therefore, determining CRP levels is important for correct health intervention and treatment follow-up. For the selective detection of CRP, we developed a (GO/Au-MIP) SPR sensor containing CRP-imprinted polymer modified with graphene oxide and gold nanoparticles. To prove the enhanced sensitivity of the sensor resulting from the presence of graphene oxide (GO) and gold nanoparticles (AuNPs), a CRP-imprinted (MIP) SPR sensor was prepared using the same method, excluding the incorporation of GO and AuNPs. In addition, a non-imprinted GO/Au-NIP SPR sensor was also prepared to evaluate the imprinting efficiency. In detecting CRP in PBS buffer, the GO/Au-MIP SPR sensor exhibited linearity in the concentration ranges of 0.1–2 ppm (R2 = 0.9721) and 5–100 ppm (R2 = 0.9740). The detection limit of the prepared sensor was calculated as 0.0082 ppm. In the study, the imprinting process efficiency was also evaluated by calculating the imprinting factor value (I.F=13.84). In the selectivity studies, the GO/Au-MIP SPR sensor was determined to be 9.23 times more selective against CRP protein than bovine serum albumin and 29.53 times more selective than hemoglobin. When the repeatability of the GO/Au-MIP SPR sensor was examined, it was determined that the GO/Au-MIP SPR sensor was able to detect CRP without any deterioration in performance in five consecutive reuses (RSD<1.5). Finally, CRP detection studies from the serum and urine solutions, which were selected as real samples, were carried out by the GO/Au-MIP SPR sensor to evaluate the matrix effect. CRP spiked serum sample was analyzed by the other standard method to validate the analytical results using CRP analyser.

Gold Nanoparticle (GNP) Enhanced Electroporation of Extracellular Vesicles to Promote Gene Loading

Gene therapy is an emerging and powerful therapeutic tool for treating diverse diseases via functional genetic material delivery to targeted defective genes in cells. Extracellular vesicles (EVs) are natural carriers released by all living cells, which are gaining attention for usage in advancing efficiency of therapeutic delivery due to their various advantageous properties, including; (i) cargo protection from enzymatic degradation, (ii) tissue-specific targeting, and (iii) high biocompatibility. EVs can be isolated from a targeted set of cells and used for therapeutic delivery as they can travel back to the same cell type due to their unique surface proteins and markers to release the genes at the specified site. One of the leading methods for cargo transfection into EVs is electroporation, which utilizes short-duration voltage pulses to create pores on the EV surface membrane, during which the cargo can enter. The voltage creates a potential difference between the less electrically conductive EV membrane and the more electrically conductive internal and external EV environments leading to the formation of these pores. This process is limited by the maximum pulse amplitude and duration the EVs can withstand for maximum pore formation and cargo encapsulation while still permitting membrane recovery afterward. We specifically use microfluidic electroporation, which we have previously found to be the most efficient in loading. This technique utilizes water-in-oil droplet encapsulation of the EVs which are then electroporated by voltage application as they pass through parallel metal electrodes. As the droplets pass through the microfluidic device, the non-conductive oil phase creates a barrier allowing for specific consistent and short-pulsed voltage delivery for each EV-encapsulated conductive water droplet [1]. We aim to increase efficiency of gene therapy loading into EVs using gold nanoparticle (AuNP) enhanced electroporation to provide higher concentration, targeted, and protected gene delivery. It has been shown that AuNP can increase the loading into cells during electroporation by allocating the electric voltage onto the cell surface creating a pulse strength focusing effect, allowing more pore formation without increasing the total voltage applied [2]. Due to similar surface properties, we hypothesized that AuNPs would provide a similar increase in transfection of EVs. To test this hypothesis, we electroporated green fluorescence protein (GFP) into EVs with the introduction of AuNPs at various concentrations. Fluorescence analysis through Cytation 5 and EV concentration measurement with Nanoparticle Tracking Analysis (NTA) revealed a close to double increase in the GFP molecules per EV with the AuNP incorporation. Assessment with NTA and Transmission Electron Microscopy showed that the AuNPs did not significantly change the size, concentration, zeta potential, or morphology of the EVs, compared to the native EVs without electroporation, for retaining the EV originality and integrity. Overall, AuNPs have the capacity to increase cargo transfection into EVs, allowing high-efficiency packaging for specific therapy delivery to enhance effectiveness of the treatment.[1] Geng, T., & Lu, C. (2013). Microfluidic electroporation for cellular analysis and delivery. Lab Chip, 13(19), 3803–3821. https://doi.org/10.1039/c3lc50566a[2] Zu, Y., Huang, S., Liao, W.-C., Lu, Y., & Wang, S. (2014). Gold Nanoparticles Enhanced Electroporation for Mammalian Cell Transfection. Journal of Biomedical Nanotechnology, 10(6), 982–992. https://doi.org/10.1166/jbn.2014.1797 Figure 1

Ultrasensitive Aptasensing Platform for the Detection of β-Amyloid-42 Peptide Based on MOF Containing Bimetallic Porphyrin Graphene Oxide and Gold Nanoparticles.

The prompt detection of diseases hinges on the accessibility and the capability to identify relevant biomarkers. The integration of aptamers and the incorporation of nanomaterials into signal transducers have not only expedited but also enhanced the development of nanoaptasensors, enabling heightened sensitivity and selectivity. Here, the bimetallic nickel-cobalt-porphyrin metal-organic framework ((Ni + Cu)TPyP MOF) is regarded as an electron mediator, immobilization platform for an Alzheimer aptamer and to increase the electrochemical signal for the detection of the main biomarker of Alzheimer's disease (AD), amyloid β (Aβ-42). Furthermore, the ((Ni + Cu)TPyP MOF) was combined with reduced graphene oxide (rGO) and gold nanoparticles (AuNPs), on a gold electrode (GE) to provide an efficient interface for immobilizing aptamer strands. Concurrently, the incorporation of rGO and AuNPs imparts enhanced electrical conductivity and efficacious catalytic activity, establishing them as adept electrochemical indicators. Owing to the superior excellent electrical conductivity of rGO and AuNPs, coupled with the presence of ample mesoporous channels and numerous Ni and Cu metal sites within (Ni + Cu)TPyP MOF, this nanostructure with abundant functional groups is proficient in immobilizing a substantial quantity of aptamer. These interactions are achieved through robust π-π stacking and electrostatic interactions, alongside the high affinity between the thiol group of the aptamer and AuNPs concurrently. The as-prepared ternary (Au@(Ni + Cu)TPyP MOF/rGO) nanostructure electrode exhibited an enhancement in its electrochemically active surface area of about 7 times, compared with the bare electrode and the Aβ-42 redox process is highly accelerated, so the peak currents are significantly higher than those obtained with bare GE substrate. Under the optimized conditions, the designed aptasensor had the quantitative detection of Aβ-42 with a low detection limit of 48.6 fg mL-1 within the linear range of 0.05 pg mL-1 to 5 ng mL-1 by differential pulse voltammetry (DPV), accompanied by precise reproducibility, satisfactory stability (95.6% of the initial activity after 10 days), and minimal impact of interfering agents. Recorded results in human blood plasma demonstrated the high efficacy of porphyrin MOF system sensing even in the clinical matrix. The great performance of this aptasensor indicates that our new design of Au@(Ni + Cu)TPyP MOF/rGO nanostructure provides more opportunities for the detection of chemical signals in early diagnosis of Alzheimer's disease.

Synthesis and Characterization of AuNP/TiO&lt;sub&gt;2&lt;/sub&gt; Hybrid Nanoparticles for Possible Photocatalytic Application

Nanoparticles have been intensively studied due to their unique, size-dependent properties, paving the way for various applications, particularly in photocatalysis. This study aims to determine the physicochemical characteristics of TiO2 and Au nanoparticles and the AuNP/TiO2 hybrid nanoparticles. Employing multiple characterization techniques, the structural and functional parameters were elucidated. The Brunauer-Emmett-Teller (BET) surface area analysis revealed the pore sizes of TiO2 and the Au/TiO2 hybrid nanoparticles as 12 nm and 18 nm, respectively. The Dynamic light scattering (DLS) measurements revealed the hydrodynamic size of the AuNP/TiO2 hybrid nanoparticles at 386 nm. The UV-visible spectroscopy showed the absorbance peaks associated with their electronic structures and potential photocatalytic applications. The fast Fourier infrared (FTIR) spectroscopy results revealed the surface molecular interactions crucial for nanoparticle functionalities. The AuNP/TiO2 hybrid nanoparticles exhibit a larger pore size compared to TiO2NPs, indicating their superior adsorption capability. Moreover, the unique band gap of TiO2NPs and electron-hole pair generation make it a formidable candidate for photocatalysis. The incorporation of AuNPs may further augment charge separation, optimizing photocatalytic activity. These findings spotlight the promise of these AuNP/TiO2 hybrid nanoparticles in possible photocatalytic applications.

Photoelectrochemical pathogenic bacteria sensing platform integrated with sterilization function based on the g-C3N4 nanosheets decorated with AuNPs and Poly(3-thiophene boronic acid)

The integration of sterilization capabilities into sensing platforms is a crucial step in mitigating the significant health risks associated with the persistence of pathogenic bacteria. In this study, we developed a photoelectrochemical (PEC) pathogenic bacteria sensing platform integrated with sterilization function. The platform was based on the g-C3N4 nanosheets decorated with AuNPs and Poly(3-thiophene boronic acid) (PTBA). The incorporation of AuNPs and PTBA proved highly beneficial for enhancing the PEC and photocatalytic performance of bulk g-C3N4. Leveraging the boronic acid group of PTBA, we achieved the selective capture of pathogenic bacteria on the surface of the electrode. The platform showed a high detection sensitivity towards Escherichia coli (E. coli) with a low limit detection (30.5 cfu/mL). Furthermore, the sensing platform demonstrated an exceptional antibacterial rate (99.9 %) resulting from the photoelectrocatalytic effect of PTBA/AuNPs/g-C3N4. This research presents a potential application of the platform as a self-cleaning biosensor for pathogenic diagnosis.

Silica Gels Doped with Gold Nanoparticles: Preparation, Structure and Optical Properties.

A novel, one-pot sol-gel preparation scheme leading to reproducible incorporation of 20-40 nm sized gold nanoparticles (AuNPs) in SiO2 gels is developed based on in situ reduction during gelation using chloroauric acid and ascorbic acid. Variation in the preparation conditions affects the chemical composition, optical properties and size distribution of the AuNPs incorporated in the silica gels. Different organic dopants, i.e., oleic acid, acetic acid or dodecanethiol, are applied to modify the final composite material and to control the rate of reduction and growth of the AuNPs in the gels. The synthesized samples are characterized by UV/Vis/NIR spectroscopy, X-ray diffraction, transmission electron microscopy, thermal conductivity measurements and DTA/TG measurements. The optical properties of the obtained composites are explained using Mie theory. The incorporation of AuNPs leads to an increase in the thermal conductivity of the silica gels. The best process method in this contribution is the use of NaOH as a gelation catalyst and oleic acid as an organic modifier, leading to 20 nm AuNPs dispersed in the silica matrix.

Growth of tunable Au-BaO@TiO2/CdS heterostructures: Acceleration of hydrogen evolution from water splitting

The need for efficient and sustainable catalysts to generate clean energy through water splitting is a requirement of the current era. In this study, TiO2/CdS heterostructures were synthesized using hydrothermal reaction. To enhance the photocatalytic performances of TiO2/CdS, BaO and Au were in-situ deposited via chemical reduction and hydrothermal treatment at 165 °C for 6 h. Finally Au-BaO@TiO2/CdS catalysts were synthesized for photocatalytic hydrogen generation from water splitting. The optical and structural properties of catalysts were examined with FT-IR, XRD, Raman and UV–Vis-DRS techniques. The morphology and chemical properties of catalysts were obtained using EDX, AFM, XPS and SEM techniques. Photoreaction and H2 production activities were monitored at Pyrex reactor (150 mL) and GC-TCD (Shimadzu-2014). The tunable fabrication approach provides a novel strategy for tailoring the properties of TiO2/CdS heterostructures, allowing for optimization of their photocatalytic performance. The enhanced surface plasmon impact achieved through Au-NPs incorporation opens up new possibilities for improving the efficiency. The results demonstrate that Au-BaO@TiO2/CdS catalysts exhibit significantly higher H2 generation activity (13.54 mmol g−1h−1). This H2 evolution activity was found higher than other catalysts i.e. TiO2/CdS, BaO@TiO2/CdS and Au@TiO2/CdS. Higher catalytic activity in case of Au-BaO@TiO2/CdS was attributed to the co-existence of BaO and Au-NPs. The Au-NPs provide hot electrons (via SPR effect) that increase the electron pool over the surfaces of TiO2/CdS heterostructures. During photoreaction, BaO assists the transfer of photoexcited electrons from TiO2/CdS system to the active centers (i.e. Au cocatalysts). In addition, various factors that affect the H2 production rates (i.e. pH, temperature, catalyst dose and effect of light intensity) were evaluated and discussed.

Effects of Hydrophobic Gold Nanoparticles on Structure and Fluidity of SOPC Lipid Membranes.

Gold nanoparticles (AuNPs) are promising candidates in various biomedical applications such as sensors, imaging, and cancer therapy. Understanding the influence of AuNPs on lipid membranes is important to assure their safety in the biological environment and to improve their scope in nanomedicine. In this regard, the present study aimed to analyze the effects of different concentrations (0.5, 1, and 2 wt.%) of dodecanethiol functionalized hydrophobic AuNPs on the structure and fluidity of zwitterionic 1-stearoyl-2-oleoyl-sn-glycerol-3-phosphocholine (SOPC) lipid bilayer membranes using Fourier-transform infrared (FTIR) spectroscopy and fluorescent spectroscopy. The size of AuNPs was found to be 2.2 ± 1.1 nm using transmission electron microscopy. FTIR results have shown that the AuNPs induced a slight shift in methylene stretching bands, while the band positions of carbonyl and phosphate group stretching were unaffected. Temperature-dependent fluorescent anisotropy measurements showed that the incorporation of AuNPs up to 2 wt.% did not affect the lipid order in membranes. Overall, these results indicate that the hydrophobic AuNPs in the studied concentration did not cause any significant alterations in the structure and membrane fluidity, which suggests the suitability of these particles to form liposome-AuNP hybrids for diverse biomedical applications including drug delivery and therapy.

Contact lenses that transform gold into nanoparticles for prophylaxis of light-related events and photothermal therapy

This work describes for first time how anisotropic gold nanoparticles (AuNPs) can be spontaneously formed inside preformed contact lenses (CLs) avoiding the use of additional reductant agents (reagent-free) through a precise tunning of the monomeric composition, the saline concentration, and the application of steam heat sterilization. Protocols to generate AuNPs in solution using inorganic or small organic reductants are widely available. Differently, gold precursors interactions with polymer networks have been overlooked and, thus, the interest of chemically cross-linked hydrogels as organic reductants is still to be elucidated. In the ocular field, incorporation of AuNPs to CLs may expand their applications in prophylaxis, therapy and diagnosis. To carry out the work, a variety of hydrogels and commercially available CLs were incubated with gold salt solution without any other chemical reagent. AuNPs formation was monitored by changes in localized surface plasmon resonance (LSPR) bands and quantifying the gold sorbed. Only silicone hydrogels induced AuNPs formation at room temperature in few days; methacrylic acid red-shifted the LSPR band (550–600 nm), while monomers bearing F hindered the reduction. Storage of hydrogels in the gold precursor solution allowed a gradual formation of anisotropic AuNPs, which could be stopped at any time by washing the hydrogel with water. The developed CLs behave as efficient filters against highly penetrant light and also exhibit photoresponsiveness as demonstrated as rapid (10 s), focused mild hyperthermia when irradiated with green, red and NIR lasers.

Electrochemical Immunosensor for Early Detection of β-Amyloid Alzheimer's Disease Biomarker Based on Aligned Carbon Nanotubes Gold Nanocomposites.

Beta-amyloid (βA) peptides accompanying the physiological change in brain induce Alzheimer's disease. In this work, a highly sensitive electrochemical (EC) immunosensor platform has been developed for the quantitative detection of βA peptides, using the gold nanoparticle functionalized chitosan-aligned carbon nanotube (CS-aCNT-Au) nanocomposites on glassy carbon electrodes (GCE). The immunosensor has been fabricated by immobilization of the anti-βA antibody upon CS-aCNT-Au/GCE. In the CS-aCNT nanocomposite, CS has high biocompatibility. Hydroxy and amine functionalities favor the antibody immobilization and prevent the leaching of nanocomposites of the modified electrode due to the adhesive environment. Moreover, aCNT offers high conductivity, stability, and a large surface area (the calculated effective surface area of the CS-aCNT/GCE is 8.594 × 10-2 cm2). However, the incorporation of AuNPs further enhances the conductivity of the CS-aCNT-Au nanocomposite based on differential pulse voltammetry (DPV) results, and also improves the effective surface area (9.735 × 10-2 cm2). The surface morphology and electrochemical studies of the nanocomposite, as well as its modifications by the anti-βA antibody and BSA, were carried out through field emission scanning electron microscope (FESEM), cyclic voltammetry (CV), and DPV. The quantitative immunosensing of the βA in phosphate-buffered saline (PBS) solution is accomplished via DPV, which reveals that the immunosensor has a high sensitivity of 157.60 µA pg-1 mL cm-2 and a broad detection range of 10.0 pg mL-1-100.0 µg mL-1, with a limit of detection (LOD) of 0.87 pg mL-1. Subsequently, we detected the spiked βA in diluted serum with a linear detection range of 10.0 pg mL-1-1.0 ng mL-1 and LOD of 0.95 pg mL-1. Moreover, a selectivity study exhibited a high affinity of immunosensors towards βA. Thus, we propose that this highly efficient immunosensor can potentially be applied for the point-of-care (POC) sensing of βA in clinical samples.

Impact of reaction parameters for photodegradation pharmaceuticals in wastewater over gold/titania photocatalyst synthesized by pyrolysis of NH2-MIL-125(Ti)

The efficient remediation of pharmaceuticals, including wastewater, remains a remarkably challenging issue for water regeneration. Herein, porous Au/TiO2 synthesized by pyrolysis of NH2-MIL-125(Ti) was utilized to be an efficient photocatalyst for mineralization of trimethoprim (TMP) and Metronidazole (MNZ) as the parent compound. The effects of different factors, including TMP and MNZ concentrations, light intensity, H2O2 concentration, Au/TiO2 dosage, and pH value of reaction solution on the degradation and mineralization performances during UV and visible light (VIS), were addressed. The porous Au/TiO2 photocatalyst exhibited superior photocatalytic degradation of TMP and MNZ under UV and VIS illumination. The optimum pH values were 4; the optimum dosage of Au/TiO2 was 1.5 g/L, H2O2 concentration was 9.8 mM, TMP and MNZ concentrations was 10 ppm, and their photodegradation efficiency was 100% after 30 min illumination time and mineralization efficiency 98.2% after 3 h illumination for TMP and MNZ, respectively under UV illumination, however, the photodegradation efficiency was 100% after 50 min illumination and mineralization efficiency 96.3% after 4.5 h illumination time for TMP and MNZ, respectively under VIS illumination. The real wastewater matrix with 10 mg/L of TMP and MNZ were subjected to 60 min of illumination under similar optimum conditions of synthetic solution. The results indicated that photodegradation efficiency was determined to be 100% after 70 min illumination time for removal of both TMP (k = 3.4 × 10−2 min−1) and MNZ (k = 2.87 × 10−2 min−1). This is ascribed to the incorporation of Au NPs onto TiO2, reducing the photoinduced electron-hole recombination, thus promoting the photocatalytic performance. The possible mechanism for photodegradation of antibiotics was also discussed. The demonstration of photocatalysis mechanism over Au/TiO2 photocatalyst can provide some directing in the enhancement of novel photocatalysts based on MOFs doped by noble metal.

Growth of gold-aryl nanoparticles in lysozyme crystals

Hen egg-white lysozyme crystals are an exemplary system for the growth of gold-aryl nanoparticles within proteins. We investigated the growth of AuNPs functionalized with carboxyl groups in a single protein crystal of lysozyme (Lys@AuNPs) by the protein reduction of aryldiazonium tetrachloroaurate(III) salt [COOH-4-C6H4NN]AuCl4 over 30, 60, and 90 days. We studied the time-dependent, in situ, and gradual growth of AuNPs within single crystals of lysozyme in precipitant solution of 6.5% NaCl in 0.1 M sodium acetate at pH 4.5. The growth and incorporation of AuNPs inside the lysozyme crystals were confirmed by HR-TEM measurements and microscopy imaging. Investigation of TEM images indicates that AuNPs matured progressively beginning with an average size of 48.5 ± 5.7 nm after 30 days. More numbers of AuNPs of 20.8 ± 4.4 nm and 19.2 ± 5.4 nm after 60 and 90 days, respectively, were formed within the lysozyme crystals. Furthermore, we observed that the addition of Hg2+ can expedite the formation of Lys@AuNPs crystals. The color of the gold nanoparticles was developed after 8 days in the presence of Hg2+. The formed AuNPs were mostly spherical with an average size of 13.9 ± 5.2 nm.

Nanoassembly of UCST polypeptide for NIR-modulated drug release

Multi-l-arginyl-poly-l-aspartate (MAPA), also known as cyanophycin, is a zwitterionic polypeptide. The upper critical solution temperature (UCST) response of the insoluble fraction (iMAPA) upon crosslinking with hyaluronic acid (HA) was found to be preserved over a wide pH range. The thermal reversibility of iMAPA-HA was further employed to encapsulate doxorubicin (dox) at different weight ratios of dox/polymer with and without AuNP incorporation so as to obtain light responsive nanoassemblies. Dox loading was found to be a function of both dox concentration and the presence of AuNP. Thus a maximum encapsulation efficiency of about 60% was observed for 3 mg dox/mg polymer with AuNP as compared to 35% without AuNP. The size of these nanoassemblies exhibited a range of 30–50 nm, and these nanoassemblies also displayed stability at 4 °C by morphology and dox retention for at least 4 weeks in PBS. Upon periodic irradiation for 30 s with an 808 nm laser, altering the irradiation intensity and duration could selectively manipulate the release profile and percentage by a photothermal effect. The results present a delivery system with controllable light-regulated release.

Highly efficient biomass-derived carbon@Au/ZnO novel ternary photocatalyst for ultra-fast degradation of gemifloxacin drug

The designing of highly specific visible light responsive photocatalysts requires highly dedicative efforts and still a challenging task. The current work focused to design a decidedly novel visible-light derived ternary photocatalyst based on ZnO nanostructures in conjugation with activated carbon (AC) and gold (Au) nanoparticles for environmental remediation task. The AC and AuNPs doped ZnO ternary frameworks were produced by the hydrothermal approach followed by ultra-sonication technique. The XRD data revealed hexagonal wurtzite form of ZnO while the XPS and FTIR investigation confirmed the creation of highly capable framework in conjugation with AC, AuNPs, and ZnO. The TEM images clearly revealed that AuNPs (4–10 nm) were uniformly dispersed onto ZnO nanoparticles (20–80 nm) and the AC possesses sheets like morphology (stacking pattern arrangement). The UV–vis examination demonstrates a lowering of energy band gap upon the incorporation of AC and AuNPs into ZnO matrix. The newly designed novel ternary [email protected]/ZnO photocatalyst was applied for the photocatalytic destruction of gemifloxacin mesylate antibiotic drug under visible light illumination. The impeccable [email protected]/ZnO organization displayed astonishing results with 98.0% destruction of gemifloxacin mesylate drug. The newly fabricated [email protected]/ZnO framework showed the highest degradation efficiency, which was 2.21 times compared to bare ZnO. Additionally, the [email protected]/ZnO ternary framework was found to be highly detrimental during the photodegradation of methylene blue (MB) dye under visible light illumination.

Systematic Studies of Gold Nanoparticles Functionalised with Thioglucose and its Cytotoxic Effect

AbstractIn this paper, we present systematic studies concerning the synthesis protocol, functionalisation process, characterisation and cytotoxic effects of thioglucose‐modified gold nanoparticles (TG‐AuNPs). The characterisation of AuNPs and TG‐AuNPs was performed using: scanning transmission electron microscopy (STEM), Dynamic Light Scattering (DLS) and Ultraviolet‐visible spectroscopy (UV‐vis). The modification of AuNPs with TG was confirmed by Fourier‐Transform Infrared Spectroscopy (FT‐IR) and the surface coverage was determined with High‐Performance Liquid Chromatography (HPLC). Prepared bio‐conjugates with increasing and controlled amounts of TG on AuNPS were then biologically investigated: the cell viability using the MTT assay; the uptake of AuNPs in cell culture by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP‐OES); the incorporation of AuNPs in cell structures by confocal microscopy. The obtained results suggest that bio‐conjugates disclose both good biocompatibility and low cytotoxicity, and further‐can target the cancer cells and may constitute promising potential nanocarriers of anticancer drugs.

Analytical strategy for studying the formation and stability of multilayered films containing gold nanoparticles.

The design of layer-by-layer (LbL) polyelectrolyte films including nanoparticles is a growing field of innovation in a wide range of biomedical applications. Gold nanoparticles (AuNPs) are very attractive for further biomolecule coupling to induce a pharmacological effect. Nanostructured LbL films coupled with such metallic species show properties that depend on the conditions of construction, i.e. the polymer nature and dissolution buffer. Tripartite LbL films (polycation, AuNP, and polyanion) were evaluated using two different polycationic polymers (poly(allylamine hydrochloride) (PAH), poly(ethylene imine) (PEI)) and various medium conditions (salts, i.e. phosphate, Tris or Tris-NaCl buffers, and concentration). AuNP incorporation and film stability were analysed by visible spectrophotometry, capillary zone electrophoresis, a quartz crystal microbalance, and high-performance liquid chromatography. The ideal compromise between AuNP loading and film stability was obtained using PAH prepared in Tris-NaCl buffer (0.01-0.15M). This condition allowed the formation of a LbL film that was more stable than the film with PEI and provided an AuNP quantity that was 4.8 times greater than that of the PAH-PBS-built film. In conclusion, this work presents an analytical strategy for the characterization of nanostructured multilayer films and optimization of LbL films enriched with AuNPs to design biomedical device coatings.

Effect of gold nanoparticle incorporation into oil-swollen surfactant lamellar membranes

An oil-swollen surfactant membrane is employed to measure the effects of incorporated hydrophobically functionalized gold nanoparticles (AuNPs) on the structure and dynamics of the membranes. While maintaining an average AuNP diameter of approximately 5 nm, the membrane thickness was varied from 5 nm to 7.5 nm by changing the amount of oil in the membrane. The membranes become softer as the proportion of oil is increased, while the thickness fluctuations become slower. We attribute this to an increased fluctuation wavelength. Incorporation of AuNPs in the membrane induces membrane thinning and softening. Oil molecules surround the nanoparticles in the membrane and help their relatively homogeneous distribution. AuNPs significantly alter the membrane's structure and dynamics through thinning of the membrane, increased compressibility, and possible diffusion of AuNPs inside the membrane.

Mechanical properties of new denture base material modified with gold nanoparticles.

Poly(methyl methacrylate) (PMMA) is the most commonly used material in the production of dental prostheses, and its application is often accompanied by the formation of biofilm. The aim of this work was the preparation of a PMMA/gold nanoparticles (AuNps) composite to improve the antimicrobial properties of heat-polymerised PMMA. The AuNPs were synthesised from gold (III) acetate by Ultrasonic Spray Pyrolysis (USP).In the present study, flexural strength and elastic modulus were investigated, as well as thermal conductivity, density and hardness of the PMMA/AuNps` nanocomposite, with different concentrations of AuNps. Flexural strength and elastic modulus were measured using a three-point bending test, and surface hardness was evaluated using the Vickers hardness test. The thermal conductivity of the samples was measured using the Transient Plane Source (TPS) technique. Density was determined by the pycnometry procedure. Statistical analysis was conducted on the data obtained from the experiments. The flexural strength and elastic modulus of AuNps/PMMA nanocomposites decreased for all groups containing AuNps. Thermal conductivity and density increased in all groups containing AuNps compared to the control group, but it was not significant in all groups. Vickers hardness values increased significantly with an increase in AuNps` content, with the highest value 21.45 HV obtained at 0.74 wt% of AuNps. Statistical analysis was performed by means of the SPSS 19 software package. Incorporation of AuNps into heat-polymerised PMMA resin led to decrease of the flexural strength and elastic modulus. At the same time, the density, thermal conductivity and hardness increased.

Nanofibrous cosmetic face mask for transdermal delivery of nano gold: synthesis, characterization, release and zebra fish employed toxicity studies.

This study involves the generation of gold nanoparticles (Au NPs) via a novel natural/non-toxic methodology using tea and orange-peel extracts. These were then embedded into a novel blend composed of a polyethylene oxide and gelatin (PEO-Gel) fibre mat. The scanning electron microscopy results indicated that the addition of both collagen (COL) and ascorbic acid (AA) into the PEO-Gel system (PEO-Gel-AA-COL system) enhances the Au NP incorporation into nanofibres leading to a diameter of 164.60 ± 20.95 and 192.43 ± 39.14 nm in contrast to the spraying observed with the Au PEO-Gel system alone. Releasing studies conducted over 30 min indicated that the PEO-Gel-AA-COL-orange peel Au (OpAu) system accounts for a higher content of Au release than the green tea Au (GtAu) NP system where a maximum release could be attained within 10–30 min depending on the amount of Au NPs that have been incorporated. Moreover, the transdermal diffusion studies conducted using Strat membrane indicated that Au NPs from both formulations (PEO-Gel-AA-COL-GtAu nanofibre, PEO-Gel-AA-COL-OpAu nanofibre) have diffused through the stratum corneum and trapped in the dermis and epidermis indicating its transdermal deliverability. Additionally, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealed that nanofibres have similar radical scavenging activity like AA standard. Toxicity evaluation on a zebra fish embryo model confirmed that both GtAu NPs and OpAu NPs do not induce any teratogenic activity and are safe to be used in the range of 1.0–167 µg ml−1.