scholarly journals Controlled biosynthesis of gold nanoparticles with Coffea arabica using factorial design

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Wanderson Juvencio Keijok ◽  
Rayssa Helena Arruda Pereira ◽  
Luis Alberto Contreras Alvarez ◽  
Adilson Ribeiro Prado ◽  
André Romero da Silva ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Factorial Design ◽  
Textile Industry ◽  
Coffea Arabica ◽  
Metallic Nanoparticles ◽  
High Efficiency ◽  
Antimicrobial Properties ◽  
Control Mechanisms ◽  
Solar Panels ◽  
Aromatic Molecules

Abstract Green synthesis of metallic nanoparticles has become incredibly popular, mainly by minimizing problems of environmental contamination and by being able to reduce, stabilize and potentially functionalize nanomaterials. Such compounds have possible applications in various areas, e.g., pharmaceuticals (drug delivery systems, cosmetics), textile industry (clothing with antimicrobial properties), diagnostic medicine (imaging, high efficiency biosensors), energy (solar panels), bioremediation, among others. However, the lack of reproducibility and information on the control mechanisms during synthesis have made the application of green-synthesized nanoparticles unfeasible. Thus, this study proposed the investigation of the main mechanisms affecting synthesis control, using factorial design for the preparation of gold nanoparticles with extract of Coffea arabica. We obtained stable (Zeta Potential, UV-vis and DLS), monodisperse, and quasi-spherical (TEM) nanoparticles, which presented adsorbed aromatic molecules (FTIR and RAMAN) and defined crystal structure (XRD), proving that the plant extract acted as a reducing agent, as well as a stabilizer and functionalizer for the synthesized nanostructures. The factorial design employed here to obtain gold nanoparticles with Coffea arabica extract allowed for a controlled and reproducible synthesis, enabling new possibilities for the application in several fields.

scholarly journals High Antioxidant Activity and Low Toxicity of Gold Nanoparticles Synthesized With Virola Oleífera: An Approach Using Design of Experiments

2020 ◽  
Author(s):  
Luis Contreras ◽  
Debora Ferreira ◽  
Wanderson Keijok ◽  
Laryssa Silva ◽  
André da Silva ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Gold Nanoparticles ◽  
Factorial Design ◽  
Metallic Nanoparticles ◽  
Large Scale ◽  
Optimal Path ◽  
Stability Control ◽  
Localized Surface Plasmon ◽  
High Antioxidant Activity ◽  
Low Toxicity

Abstract Metallic nanoparticles synthesized by plant extracts and biomolecules represent one of the most promising frontiers in the antioxidants field. Plant compounds apart from act as reducing agents, also allow functionalizing these nanoparticles having multiple applications in different industries. However, the low reproducibility and the difficulty in size, shape and stability control have made it difficult to produce on a large scale. Here we report an optimization process to obtain gold nanoparticles (AuNPs) from green synthesis using a factorial design aiming to present a controlled synthesis using Virola oleifera as a reductant agent. We evaluate the influence of the reaction time, temperature, stirring rate, pH and extract concentration monitoring the Localized surface-plasmon resonance (LSPR) band shift (Δλ). The nanoparticles were characterized using Zeta potential, UV-vis, DLS, TEM, Raman spectroscopy, FTIR and XRD. The as-synthesized AuNPs were stable and homogenous, octahedral, monodisperse, and in shape and size and showed great antioxidant activity determined with ABTS+ and DPPH. Furthermore, these nanoparticles presented low cytotoxicity. Finally, using the factorial design, we were able to develop an optimal path for green gold nanoparticles with high antioxidant activity, low toxicity and good morphological characteristic.

scholarly journals Nonlocal and Size-Dependent Dielectric Function for Plasmonic Nanoparticles

2019 ◽  
Vol 9 (15) ◽  
pp. 3083
Author(s):  
Kai-Jian Huang ◽  
Shui-Jie Qin ◽  
Zheng-Ping Zhang ◽  
Zhao Ding ◽  
Zhong-Chen Bai
Keyword(s):  
Metallic Nanoparticles ◽  
High Efficiency ◽  
Finite Size ◽  
Plasmonic Nanostructures ◽  
Accurate Analysis ◽  
Finite Size Effects ◽  
Size Dependent ◽  
Quantum Size ◽  
The Impact ◽  
Electron Energy Loss

We develop a theoretical approach to investigate the impact that nonlocal and finite-size effects have on the dielectric response of plasmonic nanostructures. Through simulations, comprehensive comparisons of the electron energy loss spectroscopy (EELS) and the optical performance are discussed for a gold spherical dimer system in terms of different dielectric models. Our study offers a paradigm of high efficiency compatible dielectric theoretical framework for accounting the metallic nanoparticles behavior combining local, nonlocal and size-dependent effects in broader energy and size ranges. The results of accurate analysis and simulation for these effects unveil the weight and the evolution of both surface and bulk plasmons vibrational mechanisms, which are important for further understanding the electrodynamics properties of structures at the nanoscale. Particularly, our method can be extended to other plasmonic nanostructures where quantum-size or strongly interacting effects are likely to play an important role.

scholarly journals Gold Nanoparticles Synthesis and Antimicrobial Effect on Fibrous Materials

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1067
Author(s):  
Behnaz Mehravani ◽  
Ana Isabel Ribeiro ◽  
Andrea Zille
Keyword(s):  
Gold Nanoparticles ◽  
Antimicrobial Properties ◽  
Antimicrobial Effect ◽  
Environmental Concerns ◽  
Fibrous Materials ◽  
Barrier Material ◽  
Future Studies ◽  
Textile Materials ◽  
Promising Strategy ◽  
Antimicrobial Materials

Depositing nanoparticles in textiles have been a promising strategy to achieve multifunctional materials. Particularly, antimicrobial properties are highly valuable due to the emergence of new pathogens and the spread of existing ones. Several methods have been used to functionalize textile materials with gold nanoparticles (AuNPs). Therefore, this review highlighted the most used methods for AuNPs preparation and the current studies on the topic in order to obtain AuNPs with suitable properties for antimicrobial applications and minimize the environmental concerns in their production. Reporting the detailed information on the functionalization of fabrics, yarns, and fibers with AuNPs by different methods to improve the antimicrobial properties was the central objective. The studies combining AuNPs and textile materials have opened valuable opportunities to develop antimicrobial materials for health and hygiene products, as infection control and barrier material, with improved properties. Future studies are needed to amplify the antimicrobial effect of AuNPs onto textiles and minimize the concerns related to the synthesis.

EXCITON–PLASMON INTERACTION IN MONOLAYERS OF METAL-SEMICONDUCTOR NANOSTRUCTURES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 623-627 ◽  
Author(s):  
M. HARIDAS ◽  
L. N. TRIPATHI ◽  
J. K. BASU
Keyword(s):  
Gold Nanoparticles ◽  
Metallic Nanoparticles ◽  
Near Field ◽  
Blue Shift ◽  
Optical Microscope ◽  
Peak Position ◽  
Photoluminescence Spectra ◽  
Langmuir Blodgett ◽  
Near Field Scanning ◽  
Cdse Nanorods

Effect of shape and density on the energy transfer between metallic nanoparticles and semi conducting nanostructures was studied by observing the photoluminescence spectra using near field scanning optical microscope. The monolayers of gold nanoparticles, CdSe nanorods and composite with different number ratios were prepared using Langmuir Blodgett method. The spectra collected from the films with different number ratios of CdSe and gold shows a systematic variation of peak position and intensity as a function of number density of CdSe . The photoluminescence spectra collected from composite monolayer is blue shifted compared to the spectra from CdSe nanorods monolayer. Further we observed a blue shift in peak position and reduction emission intensity with respect to increase in the fraction of gold nanoparticles and surface density. We have provided explanation for the observed behavior in terms of strong exciton–plasmon interactions in the compact hybrid monolayers.

scholarly journals Biosynthesis and Potential Applications of Silver and Gold Nanoparticles and Their Chitosan-Based Nanocomposites in Nanomedicine

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Haliza Katas ◽  
Noor Zianah Moden ◽  
Chei Sin Lim ◽  
Terence Celesistinus ◽  
Jie Yee Chan ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Metallic Nanoparticles ◽  
Cost Effective ◽  
One Pot ◽  
Silver And Gold Nanoparticles ◽  
Stabilizing Agents ◽  
Cost Effective Method ◽  
Multistep Process ◽  
Potential Applications ◽  
Biological Sources

Biosynthesized or biogenic metallic nanoparticles, particularly silver and gold nanoparticles (AgNPs and AuNPs, respectively), have been increasingly used because of their advantages, including high stability and loading capacity; moreover, these nanoparticles are synthesized using a green and cost-effective method. Previous studies have investigated reducing and/or stabilizing agents from various biological sources, including plants, microorganisms, and marine-derived products, using either a one-pot or a multistep process at different conditions. In addition, extensive studies have been performed to determine the biological or pharmacological effects of these nanoparticles, such as antimicrobial, antitumor, anti-inflammatory, and antioxidant effects. In the recent years, chitosan, a natural cationic polysaccharide, has been increasingly investigated as a reducing and/or stabilizing agent in the synthesis of biogenic metallic nanoparticles with potential applications in nanomedicine. Here, we have reviewed the mechanism of biosynthesis and potential applications of AgNPs and AuNPs and their chitosan-mediated nanocomposites in nanomedicine.

scholarly journals Photoactivated Self-Sanitizing Chlorophyllin-Containing Coatings to Prevent Microbial Contamination in Packaged Food

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 328 ◽  
Author(s):  
Gracia López-Carballo ◽  
Pilar Hernández-Muñoz ◽  
Rafael Gavara
Keyword(s):  
Antimicrobial Activity ◽  
High Efficiency ◽  
Antimicrobial Properties ◽  
Methyl Cellulose ◽  
Log Reduction ◽  
Gram Positive Bacteria ◽  
Sodium Magnesium ◽  
Pet Film ◽  
Packaged Food ◽  
Sodium Copper Chlorophyllin

Chlorophyllins are semi-synthetic porphyrins obtained from chlorophyll that—when exposed to visible light—generate radical oxygen substances with antimicrobial activity. In this work, chlorophyllins incorporated with polyethylene (PE), polyvinyl alcohol (PVOH), (hydroxypropyl)methyl cellulose (HPMC), and gelatin (G) were formulated for application as coatings in packages providing antimicrobial activity after photoactivation. First, the antimicrobial properties of two porphyrins (sodium magnesium chlorophyllin, E-140, and sodium copper chlorophyllin, E-141) were analyzed against L. monocytogenes and Escherichia coli. The results indicated that E-140 was more active than E-141 and that chlorophyllins were more effective against Gram-positive bacteria. In addition, both chlorophyllins were more efficient when irradiated with halogen lamps than with LEDs, and they were inactive in dark conditions. Then, coatings on polyethylene terephthalate (PET) film were prepared, and their effect against the test bacteria was similar to that shown previously with pure chlorophyllins, i.e., greater activity in films containing E-140. Among the coating matrices, those based on PE presented the least effect (1 log reduction), whereas PVOH, HPMC, and G were lethal (7 log reduction). The self-sanitizing effect of these coatings was also analyzed by contaminating the surface of the coatings and irradiating them through the PET surface, which showed high efficiency, although the activity of the coatings was limited to L. monocytogenes. Finally, coated films were applied as separators of bologna slices. After irradiation, all the films showed count reductions of L. monocytogenes and the usual microbial load; the gelatin coating was the most effective, with an average of 3 log reduction.

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