ADVANCES IN THE GREEN SYNTHESIS OF PLANT-BASED NANOPARTICLES AND THEIR DIVERSE APPLICATIONS

Silver nanoparticles are the most important nanoparticles in connection with the antimicrobial effect. Nowadays, the green synthesis of various types of nanoparticles is rapid, effective and produce less toxic nanoparticles often with specific properties. In our experiment we have developed and described in details various types of silver nanoparticles synthesized chemically or by the green synthesis. Nine different silver nanoparticles were synthesized, three by citrate method at different pHs (8; 9; 10), four using gallic acid at alkaline pHs (10; 11), and two by green synthesis using green tea and coffee extracts, both at pH 9. Characterisation of silver nanoparticles was performed using dynamic light scattering, scanning electron microscopy, and ultraviolet-visible absorption spectroscopy. Silver nanoparticles prepared by green synthesis showed the highest antioxidant activity and also ability for quenching of free radicals. Antibacterial activity of silver nanoparticles was determined on bacterial cultures such as Staphylococcus aureus and Escherichia coli. Silver nanoparticles synthesized using green tea and coffee extracts showed the highest antibacterial activity for both bacterial strains. Minimal inhibition concentration for both strains was found to be 65 μM at each silver nanoparticle synthesized using green synthesis.

Embedding nanosized particles in bulk thermoelectric materials is expected to lower the lattice thermal conductivity by enhancing the degree of interface phonon scattering, thus improving their thermoelectric figure of merit ZT. We have developed a wet chemical process to fabricate Bi0.5Sb1.5Te3-based thermoelectric nanocomposites which include nanometer-sized metal particles. By simple solution mixing of metal acetate precursors and Bi0.5Sb1.5Te3 powders in ethyl acetate as a medium for homogeneous incorporation, it is possible to apply various types of metal nanoparticles onto the surfaces of the thermoelectric powders. Next, bulk Bi0.5Sb1.5Te3 nanocomposites with homogeneously dispersed metal nanoparticles were fabricated using a spark plasma sintering technique. The lattice thermal conductivities were reduced by increasing the long-wavelength phonon scattering in the presence of metal nanoparticles, while the Seebeck coefficients increased for a few selected metal-decorated nanocomposites, possibly due to the carrier-energy-filtering effect. Finally, the figure of merit ZT was enhanced to 1.4 near room temperature. This approach highlights the feasibility of incorporating various types of nanoparticles into an alloy matrix starting by wet chemical routes, which is an effective means of improving the thermoelectric performance of Bi-Te-based alloys.

Chapter 1 - History, introduction, and physiochemical properties of gold nanoparticles

Nanotechnology has been applied in healthcare to cure diseases, especially cancer. Cancer is one of the heterogenous diseases which lacks symptoms in the early stage thus has made it difficult to cure at a later stage. Despite early detection, effective treatment is regarded as one of the major solutions to cure cancer. Nanomaterials play a prominent role in enhancing or replacing conventional treatments with specific and less-toxic drug delivery or therapy. The requirement and properties of nanomaterials as well as their applications in cancer therapies are discussed in this chapter. Various types of nanoparticles are available on the bench side, but these nanoparticles may lack effectiveness to treat cancer using a single treatment mode. Hence, this chapter also explores the applications of various types of hybrid nanoparticles used in multiple therapies as they have shown more effective and safer outcomes for cancer patients. The combination of cancer therapies and their successes have been discussed in this chapter which is the cutting-edge applications of cancer treatment today.

Silver Nanoparticles essentially focuses on the synthesis of nano-sized particles produced through chemical, physical and biological processes, which contribute significantly to the control of plant and animal diseases and have shown considerable promise in improving the quality of living conditions and human health. Currently, silver nanoparticles (AgNP) have shown their potential as an alternative antibacterial and antioxidant agent in many studies. The method for making silver nanoparticles, namely Green synthesis, involves the use of plants for the synthesis process of various types of nanoparticles. Green synthesis has the advantages, namely that the method is simple, environmentally friendly, non-polluting, antitoxic and cost-effective. The aim of this research is to determine the antibacterial and antioxidant activity of AgNPs. In this research, the nanoparticle solution was visually determined by the yellow-brown color change. In the spectrophotometer absorption spectrum appears at a wavelength of 425 nm. The results of determining the size distribution of silver nanoparticles using PSA show that the particle size distribution obtained has an average value of 40.5 nm and 59.6 nm for silver nanoparticles for AgNO3 concentrations of 1 mM and 2 mM, respectively. FTIR measurements are used to determine the presence of bioactive molecules that may be responsible for the stabilization that acts as a capping agent. Absorption spiked at 3.280; 2.919; 1.583; 1.379; 1.239 and 1.068 cm−1 were determined for sembung leaf extract, while silver nanoparticles showed an absorption spike at 3.368; 2.850; 1.594; 1.369; 1.244 and 1.108 cm−1. The results of XRD analysis of AgNP show that it has been successfully synthesized which can be seen from the formation of a narrow peak indicating the crystalline nature of the nanoparticles formed. The results of TEM analysis of AgNPs in this study are mixed shapes such as spherical, hexagonal and triangular shapes of silver nanoparticles. The antibacterial activity test of silver nanoparticles with sembung leaf extract with varying concentrations of AgNO3 solution was successful as indicated by the formation of an inhibition zone for Eschericia coli and Staphylococcus aureus bacteria. The results show that the antioxidant activity of AgNPs shows that the percentage of inhibition increases as the concentration of AgNPs increases from 100 to 500 ppm and ascorbic acid increases from 1 to 5 ppm.

The synthesis of metallic nanoparticles (NPs) is of high interest due to their wide range of applications in various fields. Among various types of NPs, copper and silver NPs have received considerable attention because of their unique chemical, physical and antibacterial properties and also their vast applications in various fields including electronics, optics and medicine. The antibacterial properties of these NPs are the main reason for their application in medicine, textile, water treatment and food industry. Previous studies have shown that several factors like size, shape, type of coating, the concentration of a solution containing silver and copper NPs, type of microorganisms, stability of the solution and also environmental conditions like: pH, the presence of ligand (molecule or ion to bond with the central metal and compound-complex) and the bivalent cations are effective factors in antibacterial properties of these NPs. The main purpose of this paper is to review the previous studies in order to determine the mechanism of antibacterial properties of these NPs and their influential factors due to the increasing use of these metal NPs in various fields.

Silver Nanoparticles basically focus on the synthesis of nano-sized particles produced through chemical, physical, and biological processes, which contribute significantly to the control of plant and animal diseases and have shown considerable promise in improving the quality of human living conditions and health. The method of making silver nanoparticles, namely Green synthesis, involves the use of plants for the synthesis process of various types of nanoparticles. Green synthesis has the advantages of a simple method, environmentally friendly, non-polluting, antitoxic, and cost-effective. The purpose of this study was to determine the antibacterial and antioxidant activities of AgNPs. In the spectrophotometer absorption spectrum appears at a wavelength of 450 nm. FTIR measurements were used to determine the presence of bioactive molecules that may be responsible for the stabilization that acts as a capping agent. The absorption spikes at 3256, 1552, 1048, and 934 cm−1 were determined for gempur batu leaf extract, while silver nanoparticles showed absorption spikes at 3369, 1576, 1080, and 822 cm−1. The results of XRD analysis of AgNPs showed that they had been successfully synthesized, which can be seen from the formation of narrow peaks indicating the crystalline nature of the formed nanoparticles. The results of TEM analysis of AgNPs in this study are a mixture of spherical, hexagonal, and triangular shapes of silver nanoparticles. The antibacterial activity test of silver nanoparticles with gempur batu leaf extract with variations in AgNO3 solution concentration has been successful, which is indicated by the formation of inhibition zones for Eschericia coli and Staphylococcus aureus bacteria. The results of antioxidant activity in AgNPss show an increasing percentage of inhibition along with increasing concentration of AgNPss increasing from 1 to 15 ppm and ascorbic acid increasing from 1 to 5 ppm. Antibiofilm activity in AgNPs has a good ability to inhibit the formation of biofilm layers in Staphylococcus aureus and Escherichia coli bacteria by having a biofilm inhibition percentage of more than 50%.

Eco-friendly synthesis of metal nanoparticles has accrued utmost interest by researchers in the last decade for their distinct properties making them applicable in different fields of science and technology. With regard to its low cost, low environmental effect, zero contamination and higher reducing potential, their synthesis by green chemistry procedure is an emerging area in nanobiotechnology. Plant-based nanoparticles produced are more stable, with high rate of synthesis and are suitable for large scale biosynthesis as compared to the use of microorganisms which require stringent control on cell cultures. Plant-based nanoparticles have advantages over other methods due to presence of biomolecules acting both as capping and reducing agents by increasing the rate of reduction and stabilization of nanoparticles. Furthermore, secondary metabolites present in plants are used for reducing metal ions in single step reaction. In this review paper, we have cited 265 research articles and have outlined 106 plant extract assisted gold and silver nanoparticles. The present review highlights the achievements of metal nanoparticle synthesis, especially silver and gold nanoparticles from plant extracts, along with factors liable for the synthesis of metal nanoparticles. It also focuses on the dye degrading properties and various biological activities of metal nanoparticles, their antimicrobial mechanism of action and the physicochemical properties that influence the biological effects of metallic nanoparticles. Biological activities of metal nanoparticles were also described, including the effect of physicochemical properties of metal nanoparticles on biological activities.

BackgroundNanotechnology's rapid development has been in great demand, particularly for silver nanoparticles, which are useful in a variety of industries including medicine, textiles, and home appliances. Silver nanoparticles are extremely essential due to their unique physicochemical and antibacterial properties, which can be used in a variety of applications. Green synthesis is an environmentally friendly alternative to conventional synthesis because it uses fewer chemical reagents and lowers temperature and pressure. Aloe vera and Thuja orientalis have a wide medical use because it contains a large number of compounds derived and was decided to use for the synthesis of nanoparticles.Main textThe combination of silver nanoparticles has a wide range of applications, which has encouraged researchers to focus on the methods for the synthesis of silver nanoparticles from Aloe vera and Thuja orientalis leaves extract, characterization techniques of synthesized silver nanoparticles, and evaluation of their antimicrobial and antifungal activities. The synthesized AgNPs can be characterized by using various analytical techniques including UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), etc. The various types of silver nanoparticles, various strategies for silver nanoparticle synthesis, nano-based drug delivery systems, taxonomy and chemical constituents of Aloe vera and Thuja orientalis plants, the general mechanism of action of silver nanoparticles in bacteria, and various applications of silver nanoparticles have also been discussed.ConclusionThis review covers a wide range of research on silver nanoparticles to gain a better understanding of their physicochemical feature characterization, production, mechanisms of action, and applications. Various AgNP factors, such as size, surfactant, and structural shape, influence the unique physicochemical properties of these nanoparticles. Even though there are a variety of ways to make AgNPs, green synthesis has a high yield and biocompatibility because it uses natural agents and harmless chemicals. In this paper, we describe the green manufacture of silver nanoparticles utilizing Aloe vera and Thuja orientalis leaf extracts, as well as the method to test their antimicrobial and antifungal activity.

Metal nanoparticles (MNPS) with unique and size-related optical properties that differ greatly from those at the bulk and atomic levels are included in the broad area of nanoscience. Silver nanoparticles (AgNPs) one of the noble MNPS, have special characteristics for metal interaction. Copper (Cu) and silver (Ag) Nanoparticles can be synthesized by using different methods, including chemical, physical, biological and green synthesis techniques. The synthesis of nanoparticles through the use of plants represents biological method that is both environmentally friendly and cost-effective. We produce two types of nanoparticles: one being silver nanoparticles (Ag-NPs) and the other copper nanoparticles (Cu-NPs). The chemical methods of nanoparticles synthesis pose health hazards and environmental risks; the biological method of nanoparticles synthesis is significantly more environmentally friendly and safe for use. Green synthesis, which involves the use of plant extract, bacteria and fungi an eco-friendly approach to nanoparticles production. Controlling the particle size – dependent properties of these nanoparticles enhance their potential application. While silver and gold nanoparticles are wildly studied, copper nanoparticles present a cost- effective alternative with strong antibacterial properties. This review compiles information on the synthesis, properties, stabilizing agent, application of Ag and Cu nanoparticles, their importance in biological and technological fields. Characterization by UV-Vis spectroscopy, Fourier-transform infrared Spectroscopy (FTIR), Transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic light scattering (DLS), etc. copper nanoparticles generally display a surface Plasmon resonance (SPR) peak within the range of 300-800 nm, with notable peaks occurring around 540-570 nm. Silver nanoparticles usually present a peak within the range of 390-470 nm.

BackgroundInfluenza virus is a significant cause of annual global respiratory disease and death. According to the limited availability of effective drugs and vaccines, innovative antivirals are currently being investigated as possible strategies to contain the spread of infectious agents. Among the various types of nanoparticles, silver nanoparticles (Ag-NPs) have attracted great interest due to their exceptional physicochemical properties. This study aims to investigate the antiviral activity of Ag-NPs against the influenza A virus (IAV)/H1N1.MethodsThe MTT assay was used to determine the possible cytotoxicity of the Ag-NPs. Madin-Darby canine kidney (MDCK) cells were exposed to Ag-NPs extract in conjunction with 100 cell culture infectious dose 50% (CCID50) of virus administered at time intervals during the infection process. The antiviral activity of the extract was evaluated under pre-treatment, post-treatment, and simultaneous assay. Viral titer reduction was assayed using hemagglutination (HA) and CCID50 assays. Viral RNA relative quantification by real-time Polymerase Chain Reaction approach was performed in each experimental condition.ResultsThe study yielded significant findings regarding the inhibitory effects of Ag-NPs on the IAV/H1N1. Silver nanoparticles showed dose-dependent inhibition of the virus, with the strongest effect observed when administered simultaneously with the virus which the virus titer exhibited a substantial decrease from 5 Log10 in the control group to 1 Log10 in the initial samples, further reducing to 2 Log10 per milliliter at lower concentrations. Notably, Ag-NPs demonstrated a greater reduction in virus titer during the simultaneous stage, showing a statistically significant difference (P < 0.05) between the control and experimental groups). The reduction in viral titer was also evident in both pre- and post-inoculation stages, although the effects were different.ConclusionSilver nanoparticles possess inhibitory effects on the growth of the IAV/H1N1, with a significant reduction in virus titer. These findings suggest the potential of Ag-NPs as effective antiviral agents and highlight opportunities for further research and potential clinical applications in combating IAV (H1N1) infections.

This paper explores the synthesis, characteristics, and pharmaceutical applications of metal nanoparticles, with particular focus on eco-friendly “green synthesis” methods utilizing plant-derived extracts. Nanotechnology, a concept first proposed by Nobel Laureate Richard Feynman, has rapidly evolved as a multidisciplinary field with significant implications in pharmacy, medicine, and environmental sciences. Nanomaterials, with dimensions ranging from 1 to 100 nanometers, exhibit unique physicochemical, optical, and electrical properties that enhance drug bioavailability, targeting, and therapeutic efficiency. Various types of nanoparticles are discussed, including noble metal-based (Au, Ag, Pt), bimetallic, oxide, sulfide, and carbon-based forms. Green synthesis is emphasized as a sustainable and non-toxic approach, involving the reduction of metal ions by plant secondary metabolites such as polyphenols and terpenes. This method not only reduces energy consumption and hazardous waste, but also results in stable nanoparticles with potential antioxidant and antimicrobial activities, aligning with pharmaceutical safety and efficacy standards. Moreover, the study reviews the integration of green-synthesized metal nanoparticles into voltammetric biosensors, demonstrating improved electrochemical sensitivity and selectivity for bioanalytical applications. These findings underline the potential of green nanotechnology in pharmaceutical analysis, drug delivery systems, and diagnostics. In conclusion, green synthesis of nanoparticles presents a promising strategy for the development of advanced pharmaceutical technologies, offering a safer, more sustainable alternative for nanoparticle production with broad clinical and industrial relevance.

Simple SummaryThe advancement of nanotechnology over the last three decades has given new hope to cancer management. The first FDA-approved nanomedicine (DOXIL) was made available in the market in 1995. Since then, numerous nanocarriers have been synthesized and extensively evaluated for antitumor efficacy to establish them as premier therapeutic tools. Even though nanomedicine is one of the most promising breakthroughs in the modern era of medicine, several challenges are still faced during scaling up from a laboratory setup to a clinical arrangement. In this review, we describe and compare various types of nanoparticles and their role in advancing cancer treatment. Moreover, we highlight various nanomedicines currently available for cancer therapy and nanoformulations that are through various stages of clinical testing.Cancer is one of the most prevalent diseases globally and is the second major cause of death in the United States. Despite the continuous efforts to understand tumor mechanisms and various approaches taken for treatment over decades, no significant improvements have been observed in cancer therapy. Lack of tumor specificity, dose-related toxicity, low bioavailability, and lack of stability of chemotherapeutics are major hindrances to cancer treatment. Nanomedicine has drawn the attention of many researchers due to its potential for tumor-specific delivery while minimizing unwanted side effects. The application of these nanoparticles is not limited to just therapeutic uses; some of them have shown to have extremely promising diagnostic potential. In this review, we describe and compare various types of nanoparticles and their role in advancing cancer treatment. We further highlight various nanoformulations currently approved for cancer therapy as well as under different phases of clinical trials. Finally, we discuss the prospect of nanomedicine in cancer management.

The potential of nanoparticles, which are classified as advanced fluid material, have been unlocked for improved oil recovery in recent years such as nanoparticles-assisted waterflood process. However, there is no existing commercial reservoir simulation software that could properly model phase behaviour and transport phenomena of nanoparticles. This paper focuses on the development of a novel robust advanced simulation algorithms for nanoparticles that incorporate all the main mechanisms that have been observed for interpreting and predicting performance. The general algorithms were developed by incorporating important physico-chemical interactions that exist across nanoparticles along with the porous media and fluid: phase behaviour and flow characteristic of nanoparticles that includes aggregation, splitting and solid phase deposition. A new reaction stoichiometry was introduced to capture the aggregation process. The new algorithm was also incorporated to describe disproportionate permeability alteration and adsorption of nanoparticles, aqueous phase viscosities effect, interfacial tension reduction, and rock wettability alteration. Then, the model was tested and duly validated using several previously published experimental datasets that involved various types of nanoparticles, different chemical additives, hardness of water, wide range of water salinity and rock permeability and oil viscosity from ambient to reservoir temperature. A novel advanced simulation tool has successfully been developed to model advanced fluid material, particularly nanoparticles for improved/enhanced oil recovery. The main scripting of physics and mechanisms of nanoparticle injection are accomplished in the model and have acceptable match with various type of nanoparticles, concentration, initial wettability, solvent, stabilizer, water hardness and temperature. Reasonable matching for all experimental published data were achieved for pressure and production data. Critical parameters have been observed and should be considered as important input for laboratory experimental design. Sensitivity studies have been conducted on critical parameters and reported in the paper as the most sensitive for obtaining the matches of both pressure and production data. Observed matching parameters could be used as benchmarks for training and data validation. Prior to using in a 3D field-scale prediction in Malaysian oilfields, upscaling workflows must be established with critical parameters. For instance, some reaction rates at field-scale can be assumed to be instantaneous since the time scale for field-scale models is much larger than these reaction rates in the laboratory.

A comprehensive investigation of the low-velocity impact response of enhanced GFRP composites with single and hybrid loading of various types of nanoparticles