Green Synthesis Of Au Nanoparticles Research Articles

Photothermal and radiotherapy with alginate-coated gold nanoparticles for breast cancer treatment

Radiation therapy and phototherapy are commonly used cancer treatments that offer advantages such as a low risk of adverse effects and the ability to target cancer cells while sparing healthy tissue. A promising strategy for cancer treatment involves using nanoparticles (NPs) in combination with radiation and photothermal therapy to target cancer cells and improve treatment efficacy. The synthesis of gold NPs (AuNPs) for use in biomedical applications has traditionally involved toxic reducing agents. Here we harnessed dopamine (DA)-conjugated alginate (Alg) for the facile and green synthesis of Au NPs (Au@Alg-DA NPs). Alg-DA conjugate reduced Au ions, simultaneously stabilized the resulting AuNPs, and prevented aggregation, resulting in particles with a narrow size distribution and improved stability. Injectable Au@Alg-DA NPs significantly promoted ROS generation in 4T1 breast cancer cells when exposed to X-rays. In addition, their administration raised the temperature under a light excitation of 808 nm, thus helping to destroy cancer cells more effectively. Importantly, no substantial cytotoxicity was detected in our Au@Alg-DA NPs. Taken together, our work provides a promising route to obtain an injectable combined radio enhancer and photothermally active nanosystem for further potential clinic translation.

Catechin mediated green synthesis of Au nanoparticles: Experimental and theoretical approaches to the determination HOMO-LUMO energy gap and reactivity indexes for the (+)-epicatechin (2S, 3S)

This work suggests a green method for synthesizing Au nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The mechanism of green synthesized AuNPs was examined by molecular electrostatic potential (MEP) calculations. AuNPs were characterized with different techniques such as Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and Transmission electron microscopy (TEM). Electrochemical investigation of modified glassy carbon electrode using AuNPs (AuNPs/GCE) shows that the electronic transmission rate between the modified electrode and [Fe (CN) 6 ] 3−/4− increased. Process of oxidation, energy gap, and chemical reactivity indexes of the (+)-epicatechin (2S,3S) were investigated using electrochemical techniques (cyclic voltammetry (CV) and differential pulse voltammetry (DPV) as well as UV–Visible spectroscopy and compared with quantum mechanical calculations. DPV and CV were used to obtain HOMO energies of the (+)-epicatechin (2S,3S), an optical energy gap was obtained from the UV–Vis spectroscopy. Frontier molecular orbitals analysis (FMO) and reactivity indexes such as chemical hardness (ŋ), electrophilicity (ώ), electronic chemical potential (μ), electron acceptor power (ώ + ), electron donor power (ώ − ) were determined with functional theory (DFT) calculations. In summary, the HOMO energy obtained from the experimental analyses (E HOMO (from DPV) = -5.24 eV, and E HOMO (from CV) = -5.28 eV) has a relative agreement with the HOMO energy calculated by B3LYP/6–31 g (d, p) including the solvent effect (water) (E HOMO (from B3LYP) = -5.75 eV). Also, UV–Vis spectroscopy gives the bandgap energy equal to 4.31 eV, while the 4.13 eV is calculated by TD-DFT-b3lyp/6–31 + g(d).

Comparison of polyampholyte derivative of chitosan with bisphthalimides of low molecular weight in the green synthesis of Au nanoparticles

Comparison of polyampholyte derivative of chitosan with bisphthalimides of low molecular weight in the green synthesis of Au nanoparticles

Facile preparation of Au nanoparticles mediated by Foeniculum Vulgare aqueous extract and investigation of the anti-human breast carcinoma effects

This experiment evaluated antioxidant, anti-human breast cancer activities, and cytotoxicity effects of green synthesis of Au nanoparticles (AuNPs) containing Foeniculum Vulgare aqueous extract. Mixing Foeniculum Vulgare aqueous with Au chloride solution produced Au nanoparticles. The characteristics of Au nanoparticles determined using Fourier Transformed Infrared Spectroscopy (FT‐IR), Transmission Electron Microscopy (TEM), UV–Visible Spectroscopy (UV–Vis), and Field Emission Scanning Electron Microscopy (FE‐SEM). To check the cytotoxicity and anti-breast cancer effects of Au chloride, Foeniculum Vulgare aqueous extract, and AuNPs on common breast cancer cell lines i.e., ZR-75-30, T47D, and HCC1187 was used MTT assay. AuNPs showed no cytotoxicity and the most effective anti-breast cancer features compared to other items that were tested. They had no cytotoxic effects on normal cell line (HUVEC) and had very low cell viability, high anti-breast cancer activities dose-dependently against ZR-75-30, T47D, and HCC1187 cell lines. In the presence of butylated hydroxytoluene as the positive control, the DPPH test was used to evaluate the antioxidant features of Au chloride, Foeniculum Vulgare aqueous extract, and Au nanoparticles. AuNPs showed the best antioxidant properties compared to other items that were tested. Perhaps remarkable anti-human breast cancer activities of Au nanoparticles synthesized by Foeniculum Vulgare aqueous extract due to its antioxidant properties. After clinical trial and confirmation of results, this formulation can be used as an effective drug to treat breast cancer.

Phytogenic synthesis of gold nanoparticles and applications for removal of methylene blue dye: A review

Abstract Clean and ample supplies of water for better health, society, economy, and environment are crucial. Industrial revolutions have substantially polluted the environment and we are facing intimidating challenges in meeting rising demands of potable and safe water for society and the environment. One of the stern causes for pollution of water bodies is the dumping of industrial effluents without proper treatment in water reservoirs and has become a concern for the whole world and international bodies. Amid, the dumping of effluent containing different dyes by textile, dyeing, printing, and paper industries are threatening. Nanotechnology plays a crucial role in using its remarkable applications to keep the environment safe and clean by eradicating venomous and unsafe materials from nature. Nanotechnology is an excellent tool to degrade the unwanted and harmful materials extant in essential water sources used by humans and animals. There are various kinds of nanomaterials explored for the successful removal of pollutant from water very effectively due to their unique properties like greater surface area, shapes, and ability to work at low concentrations, etc. The nanostructured catalytic membranes, nanosorbents and nanophotocatalyst based approaches to remove pollutants from wastewater are eco-friendly and efficient. In this review article, attempt was made to congregate the various reports on green synthesis of Au nanoparticles (Au NPs) using extract of various parts of plant, their characterizations using different spectroscopic, microscopic techniques and applications for removal of methylene blue (MB) dye from the solution.

Desarrollo de un sustrato flexible y activo para SERS basado en nanoestructuras de metales nobles (Au y Ag)/poliestireno

La necesidad de contar con sistemas de detección altamente sensibles de moléculas orgánicas, que sean rápidos y asequibles para su uso en campo, ha empujado el desarrollo de dispositivos basados en el efecto SERS (por sus siglas en inglés: Surface-Enhanced Raman Spectroscopy). En el presente estudio se reporta la síntesis verde de nanopartículas de Au con Cymbopogon citratus y Citrus paradisi, con forma de estrella y triangulares respectivamente; así como la síntesis química de nanopartículas cúbicas de Ag. Las nanoestructuras fueron caracterizadas por medio de espectroscopia UV-vis y Microscopia Electrónica de Transmisión. Las nanoestructuras de Ag y Au fueron depositadas sobre una superficie de poliestireno acanalado, para evaluar estos sistemas como sustratos activos para SERS utilizando el azul de metileno como molécula objetivo. En todos los casos se consigue una mejora en las señales Raman características del azul de metileno, especialmente cuando se emplean las nanoestructuras con morfología tipo estrella de Au.

Green synthesis of gold nanoparticles using Simarouba glauca leaf extract and their biological activity of micro-organism

Increasing applications of nanoparticles (NPs) especially metallic nanoparticle plays an important role. Gold is one of the most useful metallic nanoparticles. Au NPs having unique physio-chemical characteristics and wide usage in different field applications. It is proved that Au NPs synthesized using green plants are eco-friendly, inexpensive, have good anti-microbial activities against micro-organisms. Although silver has a long history of being used as an anti-microbial, in recent years Au NPs has become a good completion for silver and it can fight against E-coli bacteria. In our research work, green synthesis of Au NPs and its applications on medical and biological.

Green synthesis of Au nanoparticles using an aqueous extract of Stachys lavandulifolia and their catalytic performance for alkyne/aldehyde/amine A3 coupling reactions.

High reaction rate and easy availability make green synthesis of metal nanoparticles noticeable. In the present study, gold nanoparticles with wide applications in different fields were synthesized by an ecofriendly method at room temperature using Stachys lavandulifolia extract as the reducing agent. Properties of the synthesized gold nanoparticles (GNP) were identified by different analytical techniques including: UV-Vis absorption spectroscopy verified presence of Au NPs in the solution while functional groups of its extract and synthesized Au NPs were determined by FT-IR. Its crystalline analysis with a fcc plane was verified by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) determined elements in the sample. Surface morphology, diverse shapes and sizes of the Au NPs were shown by scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Beginning and end destruction temperatures of the Au/S. lavandulifolia NPs were determined by thermal gravimetric analysis (TGA). The Au nanoparticles were capped with extracts, preventing them from oxidation and agglomeration and were used as an efficient heterogeneous nanocatalyst for a three-component reaction of amines, aldehydes, and alkynes (A3 coupling). A diverse range of propargylamines were obtained in good yields. Furthermore, the separation and recycling of Au/S. lavandulifolia NPs was very simple, effective, and economical.

The role of aqueous leaf extract of Tinospora crispa as reducing and capping agents for synthesis of gold nanoparticles

Environmentally friendly method for green synthesis of Au nanoparticles (AuNP) using aqueous leaf extract of Tinospora crispa (TLE) was reported. TLE has the ability for reducing and capping AuNP. Identification of active compounds in aqueous leaf extract was obtained by phytochemical analysis and Fourier transform infrared spectroscopy (FTIR). The AuNP-TLE growth was characterized using UV-Vis spectrophotometer. The particle size and the distribution of AuNP were confirmed by particle size analyzer (PSA). AuNP-TLE formation was optimized by varying the extract concentration and time of the synthesis process. UV-Vis absorption spectrum of optimum AuNP formation displayed by the surface plasmon resonance at maximum wavelength of λmax 536 nm. The PSA result showed that AuNP has size distribution of 80.60 nm and stable up to 21 days. TEM images showed that the size of the AuNP is ± 25 nm.

Green synthesis of Au nanoparticles using potato extract: stability and growth mechanism

We report on the synthesis of spherical, well-dispersed colloidal gold nanoparticles of 17.5–23.5 nm average sizes in water using potato extract (PE) both as reducing and stabilizing agent. The effects of PE content and the pH value of the reaction mixture have been studied. Formation and growth dynamics of the Au nanoparticles in the colloids were studied using transmission electron microscopy and UV-Vis optical absorption spectroscopy techniques. While the reductor content and, hence, the nucleation and growth rates of the nanoparticles could be controlled by controlling the PE content in the reaction solution, the stability of the nanoparticles depended strongly on the pH of the reaction mixture. The mechanisms of Au ion reduction and stabilization of Au nanoparticles by potato starch have been discussed. The use of common natural solvent like water and biological reductor like PE in our synthesis process opens up the possibility of synthesizing Au nanoparticles in fully green (environmental friendly) way, and the Au nanoparticles produced in such way should have good biocompatibility.

Green synthesis of gold nanoparticles using Curcuma pseudomontana essential oil, its biological activity and cytotoxicity against human ductal breast carcinoma cells T47D

Green synthesis of Au nanoparticles (AuNPs) has been of great interest because of their potential biomedical applications. In this study, we report the synthesis of AuNPs induced and cofunctionalized with Curcuma pseudomontana essential oil (EO). The AuNPs have a strong antioxidant effect and serve as effective reducing agents, inducing the immediate passivation of AuNPs. The properties of these green AuNPs were characterized by UV/vis, FTIR spectroscopy, SEM and HRTEM study of the AuNPs exhibited excellent homogeneity with an average diameter of 20 nm, with long-term stability as well as good cytotoxic, antibacterial, anti-inflammatory and antioxidant activity. The computational results indicate that there are strong interactions between the phytoconstituents and AuNPs suggesting that this novel synthetic route for AuNPs by using EO as reducing agents may be effectively exploited for nonthermal-assisted reactions and one-pot processes of biological applications.

In situ green synthesis of Au nanoparticles onto polydopamine-functionalized graphene for catalytic reduction of nitrophenol

A simple and green route was demonstrated to prepare graphene/Au NPs nanocomposite using polydopamine as surface modifier, reducing agent and stabilizer simultaneously, which exhibits remarkable catalytic activity for the reduction of 4-nitrophenol.

Yeast Extract Mannitol medium and its constituents promote synthesis of Au nanoparticles

While evaluating the potential of microorganisms to generate Au nanoparticles, we found that inclusion of HAuCl4 in Yeast Extract Mannitol (YEM) medium turns it wine red on autoclaving. UV–vis spectra and TEM investigations confirmed that alteration in color of medium was due to formation of Au nanoparticles. Yeast extract and mannitol were key components of YEM medium responsible for formation of Au nanoparticles. In general, nanoparticles formed by YEM medium, yeast extract and mannitol were nearly spherical and in the size range of ∼4–20, ∼4–12 and ∼10–20nm, respectively. PXRD analysis suggested fcc geometry of Au nanoparticles in all cases. These findings caution autoclaving of metal salts along with microbial culture medium for authentic impact assessment studies of trace/toxic metals. Our findings also furnish ideal protocol for green synthesis of Au nanoparticles using yeast extract or mannitol under sterile aqueous conditions, which may find potential application in medicine, cosmetics and engineering.

Spontaneous synthesis of gold nanoparticles on gum arabic-modified iron oxide nanoparticles as a magnetically recoverable nanocatalyst

A novel magnetically recoverable Au nanocatalyst was fabricated by spontaneous green synthesis of Au nanoparticles on the surface of gum arabic-modified Fe3O4 nanoparticles. A layer of Au nanoparticles with thickness of about 2 nm was deposited on the surface of gum arabic-modified Fe3O4 nanoparticles, because gum arabic acted as a reducing agent and a stabilizing agent simultaneously. The resultant magnetically recoverable Au nanocatalyst exhibited good catalytic activity for the reduction of 4-nitrophenol with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increase in the amount of Au nanocatalyst or decrease in the initial concentration of 4-nitrophenol. The kinetic data suggested that this catalytic reaction was diffusion-controlled, owing to the presence of gum arabic layer. In addition, this nanocatalyst exhibited good stability. Its activity had no significant decrease after five recycles. This work is useful for the development and application of magnetically recoverable Au nanocatalyst on the basis of green chemistry principles.

Green synthesis of Au nanoparticles immobilized on halloysite nanotubes for surface-enhanced Raman scattering substrates

A facile and green route was introduced to synthesize Au nanoparticles immobilized on halloysite nanotubes (AuNPs/HNTs) used for surface-enhanced Raman scattering substrates. The naturally occurring HNTs were firstly functionalized with a large amount of -NH(2) groups by N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (AEAPTES), which possesses one lone electron pair and will "anchor" Au ions to form a chelate complex. Then, with the addition of tea polyphenols (TP), the Au ions were reduced on the surface of the previously formed Au-NH(2) chelate complex to form AuNPs. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) observations indicate that a large amount of AuNPs were synthesized on HNTs. The AuNPs are irregularly spherical and densely dispersed on HNTs and the diameter of the nanoparticles varies from 20 to 40 nm. The interactions between AuNPs and -NH(2) groups were verified by X-ray photoelectron spectroscopy (XPS) and the results showed that the functional groups can "anchor" AuNPs through the chelating effect. The as-prepared AuNPs/HNTs nanomaterials with several nanometers gaps among nanoparticles were used as a unique surface-enhanced Raman scattering substrate, which possessed strong and distinctive Raman signals for R6G, indicating the remarkable enhancement effect of the AuNPs/HNTs.