scholarly journals Gold and silver nanoparticles as high-value colourants and multi-functional entities for natural fibres and minerals

2021 ◽  
Author(s):  
◽  
Kerstin Ann Burridge
Keyword(s):  
Silver Nanoparticles ◽  
Composite Materials ◽  
Gold Nanoparticle ◽  
Silver Nanoparticle ◽  
Functional Materials ◽  
Natural Fibres ◽  
Ex Situ ◽  
Gold And Silver Nanoparticles ◽  
Merino Wool ◽  
Industrial Sectors

<p>Significant opportunities exist in both the scientific and industrial sectors for the development of novel multi-functional materials that combine the inherent properties of all precursor components in a synergistic manner, thereby providing new products and opportunities. Processes that add value to natural materials in a facile and refined manner are particularly sought after. Thus this research combines useable substrates, notably natural protein fibres and minerals with gold or silver nanoparticles, producing high value, multi-functional materials that display the strength, softness and shine (of the protein fibres), or high surface area and dispersibility (of the minerals) with the high value and wealth associated with the noble metal nanoparticles, their broad spectrum of intense colours, anti-microbial, insecticide and anti-static properties. This adds significant worth to the substrates, transforming them from commodities to valuable materials.  Silk, merino wool and crossbred wool were the natural fibres employed kaolinite and halloysite clays the minerals. They were combined with gold and silver nanoparticles of various sizes and shapes (and hence colours) producing the following composite materials:  • Gold nanoparticle-merino wool composites  • Gold nanoparticle-crossbred wool composites  • Gold nanoparticle-silk composites  • Silver nanoparticle-kaolinite composites  • Silver nanoparticle-halloysite composites  The most successful method for producing silver nanoparticle-clay composites involved the external preparation of silver nanoparticles and their subsequent attachment to the clay substrates by means of a layer-by-layer deposition approach, which capitalised on electrostatic interactions between oppositely charged polyelectrolytes capping the nanoparticles and bound to the clay surfaces.  Three general approaches were employed in the production of the gold nanoparticle-natural fibre composite materials. The nanoparticles were either synthesised ex-situ and subsequently attached to the fibres, or the natural fibres were utilised as redox active biotemplates in which the wool or silk absorbed and subsequently reduced Au³⁺ to nanoparticulate Au⁰ on and within the fibres. Thirdly, a seed mediated growth approach was employed in which additional Au³⁺ was reduced to nanoparticulate Au⁰ on the surface of gold nanoparticles already bound to the fibres. This was facilitated by an external reductant.</p>

scholarly journals Gold and silver nanoparticles as high-value colourants and multi-functional entities for natural fibres and minerals

2021 ◽  
Author(s):  
◽  
Kerstin Ann Burridge
Keyword(s):  
Silver Nanoparticles ◽  
Composite Materials ◽  
Gold Nanoparticle ◽  
Silver Nanoparticle ◽  
Functional Materials ◽  
Natural Fibres ◽  
Ex Situ ◽  
Gold And Silver Nanoparticles ◽  
Merino Wool ◽  
Industrial Sectors

<p>Significant opportunities exist in both the scientific and industrial sectors for the development of novel multi-functional materials that combine the inherent properties of all precursor components in a synergistic manner, thereby providing new products and opportunities. Processes that add value to natural materials in a facile and refined manner are particularly sought after. Thus this research combines useable substrates, notably natural protein fibres and minerals with gold or silver nanoparticles, producing high value, multi-functional materials that display the strength, softness and shine (of the protein fibres), or high surface area and dispersibility (of the minerals) with the high value and wealth associated with the noble metal nanoparticles, their broad spectrum of intense colours, anti-microbial, insecticide and anti-static properties. This adds significant worth to the substrates, transforming them from commodities to valuable materials.  Silk, merino wool and crossbred wool were the natural fibres employed kaolinite and halloysite clays the minerals. They were combined with gold and silver nanoparticles of various sizes and shapes (and hence colours) producing the following composite materials:  • Gold nanoparticle-merino wool composites  • Gold nanoparticle-crossbred wool composites  • Gold nanoparticle-silk composites  • Silver nanoparticle-kaolinite composites  • Silver nanoparticle-halloysite composites  The most successful method for producing silver nanoparticle-clay composites involved the external preparation of silver nanoparticles and their subsequent attachment to the clay substrates by means of a layer-by-layer deposition approach, which capitalised on electrostatic interactions between oppositely charged polyelectrolytes capping the nanoparticles and bound to the clay surfaces.  Three general approaches were employed in the production of the gold nanoparticle-natural fibre composite materials. The nanoparticles were either synthesised ex-situ and subsequently attached to the fibres, or the natural fibres were utilised as redox active biotemplates in which the wool or silk absorbed and subsequently reduced Au³⁺ to nanoparticulate Au⁰ on and within the fibres. Thirdly, a seed mediated growth approach was employed in which additional Au³⁺ was reduced to nanoparticulate Au⁰ on the surface of gold nanoparticles already bound to the fibres. This was facilitated by an external reductant.</p>

scholarly journals In Situ and Ex Situ Designed Hydroxyapatite: Bacterial Cellulose Materials with Biomedical Applications

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4793
Author(s):  
Adrian Ionut Nicoara ◽  
Alexandra Elena Stoica ◽  
Denisa-Ionela Ene ◽  
Bogdan Stefan Vasile ◽  
Alina Maria Holban ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Composite Materials ◽  
Bacterial Cellulose ◽  
Antibacterial Properties ◽  
Antimicrobial Effect ◽  
Absorption Capacity ◽  
Coprecipitation Method ◽  
Ex Situ ◽  
Degradation Rates

Hydroxyapatite (HAp) and bacterial cellulose (BC) composite materials represent a promising approach for tissue engineering due to their excellent biocompatibility and bioactivity. This paper presents the synthesis and characterization of two types of materials based on HAp and BC, with antibacterial properties provided by silver nanoparticles (AgNPs). The composite materials were obtained following two routes: (1) HAp was obtained in situ directly in the BC matrix containing different amounts of AgNPs by the coprecipitation method, and (2) HAp was first obtained separately using the coprecipitation method, then combined with BC containing different amounts of AgNPs by ultrasound exposure. The obtained materials were characterized by means of XRD, SEM, and FT-IR, while their antimicrobial effect was evaluated against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus), and yeast (Candida albicans). The results demonstrated that the obtained composite materials were characterized by a homogenous porous structure and high water absorption capacity (more than 1000% w/w). These materials also possessed low degradation rates (<5% in simulated body fluid (SBF) at 37 °C) and considerable antimicrobial effect due to silver nanoparticles (10–70 nm) embedded in the polymer matrix. These properties could be finetuned by adjusting the content of AgNPs and the synthesis route. The samples prepared using the in situ route had a wider porosity range and better homogeneity.

A Study on Understanding Potential Gold and Silver Nanoparticle : An Overview

2020 ◽  
pp. 2150009
Author(s):  
Shadeeb Hossain
Keyword(s):  
Gold Nanoparticles ◽  
Silver Nanoparticles ◽  
Optical Property ◽  
Severe Acute Respiratory Syndrome ◽  
Silver Nanoparticle ◽  
Diagnostic Tool ◽  
Transmission Rate ◽  
Electrochemical Techniques ◽  
Gold And Silver Nanoparticles ◽  
Rapid Transmission

This paper highlights on the coronavirus outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At the time of writing this paper, there has been over 6 million confirmed cases worldwide. It is a person–person transmittable infection but there have been cases of asymptomatic carriers. Hence, development of an effective biosensing diagnostic tool can curb its rapid transmission rate. The first part of the paper highlights on the SARS-CoV-2 structure and its resemblance to SARS-CoV. The second part of the paper analyzes on the potential application of gold and silver nanoparticles to generate a red shift that had enhanced the calorimetric property of the MERS-CoV analysis due to transition in its optical property. Other electrochemical techniques that utilized the application of gold nanoparticles are also reviewed. Gold and silver nanoparticles (AuNP and Ag NP) can accelerate the sensitivity upon electrodeposition on the diagnostic tool.

scholarly journals THE USE OF Cyperus kyllinga EXTRACT IN SYNTHESIS OF SILVER NANOPARTICLE TO ENHANCE QUALITY OF GOAT LEATHER

2020 ◽  
Vol 17 (36) ◽  
pp. 159-170
Author(s):  
Eli ROHAETI ◽  
Nur Isna Melati PUTRI ◽  
Kun Sri BUDIASIH ◽  
Anna RAKHMAWATI
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Tensile Strength ◽  
Silver Nanoparticle ◽  
Ex Situ ◽  
E Coli ◽  
In Situ Method

Improving leather quality with antifungal, antibacterial, and superior mechanical properties is an ongoing effort. The objectives of this research were to synthesize silver nanoparticle using Cyperus kyllinga extract as a bio-agent and to deposit synthesized silver nanoparticle into goat leather by ex situ and in situ, and also to characterize the properties of antibacterial, antifungal, mechanical, and contact angle of goat leather before and after modification. Preparation of silver nanoparticles by reduction method by adding Cyperus kyllinga’s leaf extract. The silver nanoparticle was characterized by using spectrophotometer UltraViolet-Visible and Particle Size Analyzer. The addition of Methyltrimethoxysilane (MTMS) compound on the leather sample to know hydrophobicity properties of the leather. The leather was modified by adding silver nanoparticle and silane compounds. The antibacterial and antifungal test was conducted by the diffusion method and tested the significance by using statistical analysis. The mechanical properties were tested through tensile strength test, elongation, and also modulus Young by using a tensile tester. The modified goat leather surface was tested the contact angle by using the sessile drop method. The characterization results indicated that silver nanoparticles were formed at a wavelength of 406.60 nm, with their particle size were 200.1 nm. The results of the antimicrobial test showed that modified goat leather using two methods of preparation had a different significance to inhibit the S. epidermidis and E. coli, and also fungi of C. albicans. The leather, after modification with nanoparticle via in situ method, had the highest antibacterial activities against S. epidermidis and E. coli. However, leather after modification with adding nanoparticle and MTMS via ex situ method has the highest antifungal activity against C. albicans. The leather after modification nanoparticle and MTMS via in situ method has the highest tensile strength and the largest toughness. All modified leathers had larger antimicrobial activity, contact angle, and also toughness compared to unmodified leather.

Detection of intracellular silver nanoparticles using flow cytometry

2018 ◽  
pp. 223-226
Author(s):  
С.И. Каба ◽  
А.А. Соколовская
Keyword(s):  
Flow Cytometry ◽  
Silver Nanoparticles ◽  
Endothelial Cells ◽  
Silver Nanoparticle ◽  
Cell Uptake ◽  
Control Samples

Продемонстрировано обнаружение наночастиц серебра во внутриклеточном пространстве с помощью проточной цитофлуориметрии. В эндотелиальных клетках линии EA.hy926, инкубированных в растворе, содержащем 2 мкг/мл наносеребра, измеряли боковое светорассеяние. По сравнению с контрольными образцами этот параметр возрастал, в то время как прочие значимые характеристики не изменялись. Это подтверждает чувствительность метода к изменившемуся состоянию клеток и указывает на поглощение наночастиц серебра клетками при концентрации ниже токсической. The study demonstrated a possibility for detection of intracellular silver nanoparticles using flow cytometry. The parameter used in this work, side scattering, was measured in EA.hy926 endothelial cells incubated in a 2 mg/ml silver nanoparticle solution. This parameter was increased compared to control samples. Therefore, this technique was sensitive to changes in the cell status and suggested the cell uptake of the particles under the subtoxic conditions.

Synthesis of N ‐Acetylcysteine Conjugated Cholic Acid Stabilized Gold and Silver Nanoparticles: Evaluation of Their Catalytic Activity and Toxicity Assessment

2021 ◽  
Vol 6 (22) ◽  
pp. 5474-5487
Author(s):  
Nishanthi Ezhumalai ◽  
Manivannan Nanthagopal ◽  
Shanmugam Chandirasekar ◽  
Manikandan Elumalai ◽  
Mathivanan Narayanasamy ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Cholic Acid ◽  
Toxicity Assessment ◽  
Gold And Silver Nanoparticles

scholarly journals Isolation and Optimization of Culture Conditions of Thraustochytrium kinnei for Biomass Production, Nanoparticle Synthesis, Antioxidant and Antimicrobial Activities

2021 ◽  
Vol 9 (6) ◽  
pp. 678
Author(s):  
Kaliyamoorthy Kalidasan ◽  
Nabikhan Asmathunisha ◽  
Venugopal Gomathi ◽  
Laurent Dufossé ◽  
Kandasamy Kathiresan
Keyword(s):  
Antimicrobial Activity ◽  
Gold Nanoparticles ◽  
Silver Nanoparticles ◽  
Biomass Production ◽  
Petroleum Ether Extract ◽  
Antimicrobial Activities ◽  
Culture Conditions ◽  
Gold And Silver Nanoparticles ◽  
Optimization Of Culture Conditions ◽  
Antioxidant And Antimicrobial Activities

This work deals with the identification of a predominant thraustochytrid strain, the optimization of culture conditions, the synthesis of nanoparticles, and the evaluation of antioxidant and antimicrobial activities in biomass extracts and nanoparticles. Thraustochytrium kinnei was identified as a predominant strain from decomposing mangrove leaves, and its culture conditions were optimized for maximum biomass production of 13.53 g·L−1, with total lipids of 41.33% and DHA of 39.16% of total fatty acids. Furthermore, the strain was shown to synthesize gold and silver nanoparticles in the size ranges of 10–85 nm and 5–90 nm, respectively. Silver nanoparticles exhibited higher total antioxidant and DPPH activities than gold nanoparticles and methanol extract of the strain. The silver nanoparticles showed higher antimicrobial activity than gold nanoparticles and petroleum ether extract of the strain. Thus, Thraustochytrium kinnei is proven to be promising for synthesis of silver nanoparticles with high antioxidant and antimicrobial activity.

scholarly journals Physical and Mechanical Properties of Natural Leaf Fiber-Reinforced Epoxy Polyester Composites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1369
Author(s):  
Sanjeev Kumar ◽  
Lalta Prasad ◽  
Vinay Kumar Patel ◽  
Virendra Kumar ◽  
Anil Kumar ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Synthetic Fibre ◽  
Low Cost ◽  
Fibre Length ◽  
Physical And Mechanical Properties ◽  
Natural Fibres ◽  
Risk Environment ◽  
Insulation Property ◽  
Natural Leaf

In recent times, demand for light weight and high strength materials fabricated from natural fibres has increased tremendously. The use of natural fibres has rapidly increased due to their high availability, low density, and renewable capability over synthetic fibre. Natural leaf fibres are easy to extract from the plant (retting process is easy), which offers high stiffness, less energy consumption, less health risk, environment friendly, and better insulation property than the synthetic fibre-based composite. Natural leaf fibre composites have low machining wear with low cost and excellent performance in engineering applications, and hence established as superior reinforcing materials compared to other plant fibres. In this review, the physical and mechanical properties of different natural leaf fibre-based composites are addressed. The influences of fibre loading and fibre length on mechanical properties are discussed for different matrices-based composite materials. The surface modifications of natural fibre also play a crucial role in improving physical and mechanical properties regarding composite materials due to improved fibre/matrix adhesion. Additionally, the present review also deals with the effect of silane-treated leaf fibre-reinforced thermoset composite, which play an important role in enhancing the mechanical and physical properties of the composites.

scholarly journals Photochemical Synthesis of Gold and Silver Nanoparticles—A Review

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4585
Author(s):  
Nicole Jara ◽  
Nataly S. Milán ◽  
Ashiqur Rahman ◽  
Lynda Mouheb ◽  
Daria C. Boffito ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Surface Chemistry ◽  
Metallic Nanoparticles ◽  
Colloidal Stability ◽  
Photochemical Synthesis ◽  
Gold And Silver Nanoparticles ◽  
Future Developments ◽  
Technological Advances ◽  
Experimental Parameters ◽  
Sophisticated Equipment

Nanomaterials have supported important technological advances due to their unique properties and their applicability in various fields, such as biomedicine, catalysis, environment, energy, and electronics. This has triggered a tremendous increase in their demand. In turn, materials scientists have sought facile methods to produce nanomaterials of desired features, i.e., morphology, composition, colloidal stability, and surface chemistry, as these determine the targeted application. The advent of photoprocesses has enabled the easy, fast, scalable, and cost- and energy-effective production of metallic nanoparticles of controlled properties without the use of harmful reagents or sophisticated equipment. Herein, we overview the synthesis of gold and silver nanoparticles via photochemical routes. We extensively discuss the effect of varying the experimental parameters, such as the pH, exposure time, and source of irradiation, the use or not of reductants and surfactants, reagents’ nature and concentration, on the outcomes of these noble nanoparticles, namely, their size, shape, and colloidal stability. The hypothetical mechanisms that govern these green processes are discussed whenever available. Finally, we mention their applications and insights for future developments.

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