Structural characterization and stability study of green synthesized starch stabilized silver nanoparticles loaded with isoorientin

Synthesis, characterization, antioxidant and bacteriostasis in preservation of isoorientin loaded Zein/GA nanoparticles

Isoorientin (Iso) is a natural flavone with multiple activities. In the present study, the partial chemical properties and activities of Iso were improved by the nanoparticle loading technique. Zein/GA nanoparticles were successfully synthesized with the antisolvent precipitation method, and the structure and stability of the Zein/GA nanoparticles loaded with Iso (Zein/GA-Iso nanoparticles) were characterized by FTIR, UV-vis spectroscopy and zeta-sizer analysis. Results showed that Zein/GA-Iso nanoparticles possessed greater stability, light stability, hydrophilicity and antioxidant activity. Furthermore, Zein/GA-Iso nanoparticles exerted notable antibacterial activity against E. coli, S. aureus, and P. aeruginosa by destroying the permeability and integrity of cell membrane. On this basis, Zein/GA-Iso nanoparticles do have a bacteriostatic effect on pork. In conclusion, Zein/GA-Iso nanoparticles had better stability and pork preservation for applications in the food processing field as a new type of antiseptic and freshening agent.

Recent Advancements and Unexplored Biomedical Applications of Green Synthesized Ag and Au Nanoparticles: A Review

Green synthesis of silver (Ag) and gold (Au) nanoparticles (NPs) has acquired huge popularity owing to their potential applications in various fields. A large number of research articles exist in the literature describing the green synthesis of Ag and Au NPs for biomedical applications. However, these findings are scattered, making it time-consuming for researchers to locate promising advancements in Ag and Au NPs synthesis and their unexplored biomedical applications. Unlike other review articles, this systematic study not only highlights recent advancements in the green synthesis of Ag and Au NPs but also explores their potential unexplored biomedical applications. The article discusses the various synthesis approaches for the green synthesis of Ag and Au NPs highlighting the emerging developments and novel strategies. Then, the article reviews the important biomedical applications of green synthesized Ag and Au NPs by critically evaluating the expected advantages. To expose future research direction in the field, the article describes the unexplored biomedical applications of the NPs. Finally, the articles discuss the challenges and limitations in the green synthesis of Ag and Au NPs and their biomedical applications. This article will serve as a valuable reference for researchers, working on green synthesis of Ag and Au NPs for biomedical applications.

Development and optimization of Clitoria teratea synthesized silver nanoparticles and its application to nanogel systems for wound healing

OBJECTIVE

The present research deals with sequential optimization strategy based on Central Composite Design to optimize the process variables for efficient production of Clitoria teratea (CLT) synthesized silver nanoparticles (AgNPs) using biological synthesis.

METHODS

Two substantial factors influencing the dependent variables viz UV-visible absorbance, particle size, zeta potential and polydispersity index (PDI) were identified as NaOH concentration, RH concentration, temperature as independent variables. In-vitro and ex-vivo studies of prepared CLT-AgNPs gel and marketed gel were carried out using dialysis membrane and egg membrane, respectively. In addition, antimicrobial study was also performed on the bacterial strains.

RESULTS

The particles size (114 nm), PDI (0.45), and zeta potential (-29.5 mV) of optimized formulation were found, respectively. In-vitro profile of AgNPs from prepared CLT-AgNPs gel was noted (95.6%) in 8 h. It was found that the prepared CLT-AgNPs gel stimulates fibroblast and agranulocytosis development resulting better and timely wound healing.

CONCLUSIONS

The prepared CLT-AgNPs gel can be as a potential substitute in the management and treatment of acute and chronic wounds.

Eco-friendly Synthesis of Silver Nanoparticles and its Application in Hydrogen Photogeneration and Nanoplasmonic Biosensing

Environmentally friendly methods for silver nanoparticles (AgNPs) synthesis without the use of hazardous chemicals have recently drawn attention. In this work, AgNPs have been synthesized by microwave irradiation using only honey solutions or aqueous fresh pink radish extracts. The concentrations of honey, radish extract, AgNO3 and pH were varied. AgNPs presented mean sizes between 7.0 and 12.8 nm and were stable up to 120 days. The AgNPs were employed as co-catalyst (TiO2 @AgNPs) to increase the hydrogen photogeneration under UV-vis and only visible light irradiation, when compared to pristine TiO2 NPs. The prepared photocatalyst also showed hydrogen generation under visible light. Additionally, AgNPs were used to assemble a nanoplasmonic biosensor for the biodetection of extremely low concentrations of streptavidin, owing to its specific binding to biotin. It is shown here that green AgNPs are versatile nanomaterials, thus being potential candidates for hydrogen photogeneration and biosensing applications.

Biosynthesis of Copper Nanoparticles with Medicinal Plants Extracts: From Extraction Methods to Applications

Copper nanoparticles (CuNPs) can be synthesized by green methods using plant extracts. These methods are more environmentally friendly and offer improved properties of the synthesized NPs in terms of biocompatibility and functional capabilities. Traditional medicine has a rich history of utilization of herbs for millennia, offering a viable alternative or complementary option to conventional pharmacological medications. Plants of traditional herbal use or those with medicinal properties are candidates to be used to obtain NPs due to their high and complex content of biocompounds with different redox capacities that provide a dynamic reaction environment for NP synthesis. Other synthesis conditions, such as salt precursor concentration, temperature, time synthesis, and pH, have a significant effect on the characteristics of the NPs. This paper will review the properties of some compounds from medicinal plants, plant extract obtention methods alternatives, characteristics of plant extracts, and how they relate to the NP synthesis process. Additionally, the document includes diverse applications associated with CuNPs, starting from antibacterial properties to potential applications in metabolic disease treatment, vegetable tissue culture, therapy, and cardioprotective effect, among others.

Oliveira S, Pereira MDL, Wiart C, Wilairatana P, Eawsakul K, Rahmatullah M, Saravanabhavan SS, Nissapatorn V. Green synthesis of silver nanoparticles using Ocimum sanctum Linn. and its antibacterial activity against multidrug resistant Acinetobacter baumannii

The biosynthesis of nanoparticles using the green route is an effective strategy in nanotechnology that provides a cost-effective and environmentally friendly alternative to physical and chemical methods. This study aims to prepare an aqueous extract of Ocimum sanctum (O. sanctum)-based silver nanoparticles (AgNPs) through the green route and test their antibacterial activity. The biosynthesized silver nanoparticles were characterised by colour change, UV spectrometric analysis, FTIR, and particle shape and size morphology by SEM and TEM images. The nanoparticles are almost spherical to oval or rod-shaped with smooth surfaces and have a mean particle size in the range of 55 nm with a zeta potential of -2.7 mV. The antibacterial activities of AgNPs evaluated against clinically isolated multidrug-resistant Acinetobacter baumannii (A. baumannii) showed that the AgNPs from O. sanctum are effective in inhibiting A. baumannii growth with a zone of inhibition of 15 mm in the agar well diffusion method and MIC and MBC of 32 µg/mL and 64 µg/mL, respectively. The SEM images of A. baumannii treated with AgNPs revealed damage and rupture in bacterial cells. The time-killing assay by spectrophotometry revealed the time- and dose-dependent killing action of AgNPs against A. baumannii, and the assay at various concentrations and time intervals indicated a statistically significant result in comparison with the positive control colistin at 2 µg/mL (P < 0.05). The cytotoxicity test using the MTT assay protocol showed that prepared nanoparticles of O. sanctum are less toxic against human cell A549. This study opens up a ray of hope to explore the further research in this area and to improve the antimicrobial activities against multidrug resistant bacteria.

Metal Nanoparticle-Flavonoid Connections: Synthesis, Physicochemical and Biological Properties, as Well as Potential Applications in Medicine

Flavonoids are polyphenolic compounds widely occurring throughout the plant kingdom. They are biologically active and have many medical applications. Flavonoids reveal chemopreventive, anticarcinogenic, and antioxidant properties, as well as being able to modulate the immune system response and inhibit inflammation, angiogenesis, and metastasis. Polyphenols are also believed to reverse multidrug resistance via various mechanisms, induce apoptosis, and activate cell death signals in tumor cells by modulating cell signaling pathways. The main limitation to the broader usage of flavonoids is their low solubility, poor absorption, and rapid metabolism. To tackle this, the combining of flavonoids with nanocarriers could improve their bioavailability and create systems of wider functionalities. Recently, interest in hybrid materials based on combinations of metal nanoparticles with flavonoids has increased due to their unique physicochemical and biological properties, including improved selectivity toward target sites. In addition, flavonoids have further utilities, even in the initial step of preparation of metal nanomaterials. The review offers knowledge on multiple possibilities of the synthesis of flavonoid-metal nanoparticle conjugates, as well as presents some of their features such as size, shape, surface charge, and stability. The flavonoid-metal nanoparticles are also discussed regarding their biological properties and potential medical applications.

Synthesis of phytostabilized zinc oxide nanoparticles and their effects on physiological and anti-oxidative responses of Zea mays (L.) under chromium stress

Chromium (Cr) is a hazardous metal that has a significant risk of transfer from soil to edible parts of food crops, including shoot tissues. Reduction of Cr accumulation is required to lower the risk of Cr-exposed in humans and animals feeding on metal-contaminated parts of such plant. Zea mays is a global staple crop irrigated intensively with Cr-contaminated water. Consequently, the objective of this study was to investigate that FI-stabilized ZnO NPs could be used as an eco-friendly and efficient amendment to reduced Cr uptake and toxicity in Zea mays. To investigate the growth parameters, physiological, oxidative stress and biochemical parameters under different Cr-VI concentrations (10.0, 15.0, and 20.0 ppm). Cr exposed Z. mays plants exhibited substantially reduced plant biomass, chlorophyll contents, and altered antioxidant enzyme activity compared to untreated control. The results revealed that foliar application of Fagonia-ZnO-NPs helps eliminate the harmful effects of Cr (VI), which can enter plants through soil pollution. Increased levels of proline, soluble sugars and various antioxidant enzymes reflected this. Mean comparisons showed that Cr stress led to a 33-50% reduction in fresh shoot weight, 73-170% in fresh root weight, 16-34% shoot length, 9.5-129% root length, Chlorophyll contents 20-33% (Chl a), 18-27% (Chl b) and 17-27% (car), 14-33% total soluble sugars, 54-170% proline content, 7-7.5% POD, 0.66-75% CAT and 32-77% APX enzyme activities compared to untreated plants. Application of FI-stabilized ZnO NPs led to an increase 21-77% in fresh shoot weight, 22-45%, fresh root weight, 3-35% shoot length, 24-154% root length, Chlorophyll contents 39-60% (Chl a), 15-79% (Chl b) and 28-82% (car), 19-52% total soluble sugars, 21-55% proline content, 14-43% POD, 34-95% CAT and 130-186% APX enzyme activities under 10, 15 and 20 ppm Cr stress respectively, compared to Cr-treated plants. However, the principal component analysis revealed that chlorophyll contents, carotenoid, CAT, APX and length were in the same group and showed a positive correlation. These data collectively suggest that phytostabilized zinc oxide NPs may be an eco-friendly solution to mitigate Cr toxicity in agricultural soils and crop plants.

Flavonoids: Food associations, therapeutic mechanisms, metabolism and nanoformulations

Flavonoids possess an impressive therapeutic potential, thereby imparting them a nutraceutical character. As it becomes increasingly common to consume foods associated with healing properties, it is imperative to understand the associations of different foods with different classes of nutraceutic compounds, and their mechanisms of therapeutic action. At the same time, it is important to address the limitations thereof so that plausible future directions may be drawn. This review summarizes the food associations of flavonoids, and discusses the mechanisms responsible for imparting them their nutraceutic properties, detailing the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway, inhibition of inflammatory signaling pathways such as toll-like receptor (TLR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), cyclooxygenase 2 (COX-2) and lipoxygenase-2 (LOX-2) mediators. Further on, the review explains the mechanism of flavonoids metabolism, reasons for low bioavailability and thereafter recapitulates the role of technological interventions to overcome the limitations, with a particular focus on nanoformulations that utilize the synergy between flavonoids and biocompatible materials used as nanocarriers, as reported in works spanning over a decade. It is the Generally Recognized as Safe (GRAS) classified carriers that will become the basis for developing functional formulations. It is promisingly noteworthy that some flavonoid formulations have been commercialized and mentioned therein. Such commercially viable and safe for consumption technological applications pave way for bringing science to the table, and add value to the innate properties of flavonoids.

Biosynthesis of silver nanoparticle composites based on hesperidin and pectin and their synergistic antibacterial mechanism

Silver nanoparticles (AgNPs) were widely used in the antibacterial field because of their excellent antibacterial properties. In this study, we used hesperidin and pectin as reductants and stabilizers, and prepared uniform and stable Hesperidin-Pectin AgNPs (HP-AgNPs) by a simple microwave-assisted process. Increasing the proportion of hesperidin, P-AgNPs, HP-AgNPs1, HP-AgNPs2 and H-AgNPs were obtained respectively. With the increase of hesperidin ratio, the mean particle size and zeta potential increased gradually. Fourier transform infrared spectroscopy (FTIR) analysis showed that Ag⁺ was reduced by hesperidin and pectin. Antibacterial tests showed that HP-AgNPs2 showed the MIC values of 66.7 μg/mL against E. coli. In addition, HP-AgNPs2 was selected to clarify its antibacterial mechanism against E. coli. Morphological experiments showed that HP-AgNPs2 stress caused damage to the cell wall of E. coli, as well as leakage of its contents and an increase in reactive oxygen species (ROS). On the other hand, the release of Ag⁺ during cell co-culture was studied and the results showed that most of the Ag⁺ released was taken up by E. coli. The synergistic effect of hesperidin and pectin resulted in a significant enhancement of the antibacterial properties of AgNPs. These preliminary data suggest that HP-AgNPs has good antibacterial activity and may be developed as an effective antibacterial nanomaterial.

Structural Characterization, Antioxidant and Antibacterial Activities of a Novel Polysaccharide From Zingiber officinale and Its Application in Synthesis of Silver Nanoparticles

A novel polysaccharide (ZOP) was extracted from Zingiber officinale with ultrasonic assisted extraction method. ZOP monosaccharide composition and mole ratio is GlcA: GalA: Glc: Gal: Ara = 1.97:1.15:94.33:1.48:1.07. Then, the particle size of ZOP-NPs prepared by nano-precipitation method was 230.5 nm, and the polydispersity index (PDI) was 0.260. Using ZOP and ZOP-NPs as reductants and stabilizers, ZOP-AgNPs and ZOP-NPs-AgNPs were prepared. They were characterized by ultraviolet-visible spectrophotometer (UV-Vis), fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The silver chelation rate of polysaccharide silver nanoparticles (AgNPs) ranged from 68.70 to 82.12%. ZOP-AgNPs (0.5%, w/v; 1%, w/v) and ZOP-NPs-AgNPs (0.5%, w/v; 1%, w/v) exhibited a narrow particle size distribution of 31.1, 34.6, 25.1 and 27.6 nm, respectively. And the zeta potential values of them were−19.4,−21.6,−19.7,−23.8mV, respectively. The antioxidant and antibacterial activities of ZOP-NPs-AgNPs were superior to those of ZOP, ZOP-NPs and ZOP-AgNPs.

The aqueous assembly preparation of OPs-AgNPs with phenols from olive mill wastewater and its mechanism on antimicrobial function study

To valorise olive mill wastewater phenols (OPs) potentially applied in food preservation, a novel stable and regularly spherical OPs-AgNPs (Davg = 78 nm) were successfully assembled in aqueous solution under the optimized conditions (pH 8.0, 5 mM AgNO3, 35C and 30 min). The results of antimicrobial zone diameters indicated that 50 μg/mL of promising OPs-AgNPs presented excellent antimicrobial effects. Especially, the cell wall damages of E. coli ATCC 23,815 were caused when OPs-AgNPs concentration was exceeded its MIC (8.58 μg/mL). Also, a significant down-regulating of the Ca2+-ATPase activity in E. coli was revealed, and the intracellular Ca2+ concentrations were thus decreased from 12.5 to 1.35 µg/mL after a treatment for 3 h. The apoptosis level of E. coli was significantly increased more than the control (55.13% of OPs-AgNPs vs 9.90% of control). In sum, OPs exerts enhanced antimicrobial function via penetrating cell membrane and targeting Ca2+-ATPase after chelated with AgNPs.

Synthesis of Ziziphus spina-christi (Jujube) Root Methanol Extract Loaded Functionalized Silver Nanoparticle (ZS-Ag-NPs); Physiochemical Characterization and Effect of ZS-Ag-NPs on Adipocyte Maturation, Adipokine and Vascular Smooth Muscle Cell Interaction

In this research, a simple, green approach was employed to synthesize silver nanoparticles with the aid of Ziziphus spina-christi (L.) methanol root extract, which can act as a reducing, capping agent to treat obesity and inflammation. Globally, Ziziphus spina-christi (Jujube) root is used in traditional therapy as a lipolysis promoter. GC-MS results confirmed the availability of kaempferol (flavonol), cannabinol and indole-3-carboxylic acid in Ziziphus spina-christi root methanol extract (ZSE). ZSE silver nanoparticles (ZS-Ag-NPs) were synthesized and their effect on mitochondrial fatty acid oxidation capacity and adipokine levels in maturing adipocytes were analyzed. Maturing adipocytes treated with 0.4 µg/dL of ZSE and ZS-Ag-NPs significantly reduced the lipid content in adipocytes by 64% and 82%, respectively. In addition, lipolysis-related genes such as LPL (1.9 fold), HSL (2.3 fold), PGC-1α (3 fold), UCP-1 (4.1 fold), PRDM16 (2 fold) and PPARα (2.7 fold) increased significantly in ZS-Ag-NPs treated maturing adipocytes. The ZS-Ag-NPs treatment significantly decreased insulin resistance and metabolic inflammation-related LTB4-R, TNF-α, IL-4 and STAT-6 mRNA levels. Mitochondrial thermogenesis stimulating capacity of ZS-Ag-NPs was further confirmed by the significantly enhanced CREB-1 and AMPK protein levels in adipocytes. Furthermore, ZS-Ag-NPs treated adipokines (condition media, CM) were treated with human umbilical vein endothelial cells (HUVECs) to determine cytotoxicity and pro-inflammatory stimulus capacity. We found that ZS-Ag-NPs treated adipocyte CM effectively increased mRNA expression levels of the vascular endothelial cell growth factor (VEGF), and down-regulated oxidative stress (LPO, eNOS, and HO) and vascular cell inflammation (ICAM, VCAM, TNF-α, IL-1β, and NF-κB). In conclusion, ZS-Ag-NPs displayed an action at the molecular level in mitochondrial fatty acid oxidation, decreased adipokine secretion in adipocytes, and enhanced vascular endothelial cell growth. This molecular mechanical action of ZS-Ag-NPs reduced effectively obesity progressions and metabolic inflammatory pathogenesis associated with aging.

Plant-Extract-Mediated Synthesis of Metal Nanoparticles

Metal nanoparticles (MNPs) have been widely used in several fields including catalysis, bioengineering, photoelectricity, antibacterial, anticancer, and medical imaging due to their unique physical and chemical properties. In the traditional synthesis method of MNPs, toxic chemicals are generally used as reducing agents and stabilizing agents, which is fussy to operate and extremely environment unfriendly. Based on this, the development of an environment-friendly synthesis method of MNPs has recently attracted great attention. The use of plant extracts as reductants and stabilizers to synthesize MNPs has the advantages of low cost, environmental friendliness, sustainability, and ease of operation. Besides, the as-synthesized MNPs are nontoxic, more stable, and more uniform in size than the counterparts prepared by the traditional method. Thus, green preparation methods have become a research hotspot in the field of MNPs synthesis. In this review, recent advances in green synthesis of MNPs using plant extracts as reductants and stabilizers have been systematically summarized. In addition, the insights into the potential applications and future development for MNPs prepared by using plant extracts have been provided.

Anticancer and Antimicrobial Activity Evaluation of Cowpea-Porous-Starch-Formulated Silver Nanoparticles

Health issues involving inadequate treatment of diseases such as cancer and microbial infections continue to be the subject of much ongoing recent research. Biosynthesized silver nanoparticles (AgNPs) were characterized using Transmission Electron Microscopy (TEM), Zeta Sizer, Ultraviolet (UV), and Fourier Transform Infrared (FTIR) spectroscopy. Their antimicrobial activity was evaluated on selected Gram-positive and Gram-negative bacterial strains, using the disc diffusion and broth dilution assays. Cell viability profiles were evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptosis studies on selected human noncancer and cancer cells. The biosynthesized AgNPs were evaluated to be spherical clusters, with sizes between 40 and 70 nm. The absorption peak at 423 nm and the presence of polyphenols confirmed the synthesis and stabilization of these tested AgNPs. The AgNPs showed a good stability of −23.9 ± 1.02 mV. Good antimicrobial activity (6.0–18.0 mm) was seen on all tested bacteria at a minimum inhibitory concentration (MIC) ranging from 5 to 16 μg/ml, with the highest activity seen against Gram-negative Escherichia coli (18 ± 0.5 mm), and the lowest activity was seen against Gram-positive Listeria monocytogenes (6.0 ± 0.4 mm) after treatment with the AgNPs. These NPs showed a concentration-dependent and cell-specific cytotoxicity with low IC50 values (41.7, 56.3, and 63.8 μg/ml). The NPs were well tolerated by tested cells as indicated by a more than 50% cell viability at the high dose tested and low apoptotic indices (<0.2). These findings indicated that these biosynthesized AgNPs showed great potential as effective antibacterial agents and anticancer drug delivery modalities.

Synthesis of a BiPO4/Bi4O5I2 heterostructure for efficient degradation of oil field pollutants

In this research, composite photocatalysts were found to have a superior photocatalytic performance.