Core@shell Nanoparticles: Greener Synthesis Using Natural Plant Products

Utilization of Neem Leaf Extract on Biosynthesis of Iron Oxide Nanoparticles

The present work reports the successful synthesis of biosynthesized iron oxide nanoparticles (Fe₃O₄-NPs) with the use of non-toxic leaf extract of Neem (Azadirachta indica) as a reducing and stabilizing agent. The successful synthesis was confirmed by infrared spectra analysis with strong peak observed between 400–600 cm⁻¹ that corresponds to magnetite nanoparticles characteristics. X-ray diffraction (XRD) analysis revealed that iron oxide nanoparticles were of high purity with crystalline cubic structure phases in nature. Besides, the average size of magnetite nanoparticles was observed to be 9–12 nm with mostly irregular shapes using a transmission electron microscope (TEM) and was supported by field emission scanning electron microscope (FESEM). Energy dispersive X-ray analysis shown that the elements iron (Fe) and oxygen (O) were present with atomic percentages of 33.29% and 66.71%, respectively. From the vibrating sample magnetometer (VSM) analysis it was proven that the nanoparticles exhibited superparamagnetic properties with a magnetization value of 73 emu/g and the results showed superparamagnetic behavior at room temperature, suggesting potential applications for a magnetic targeting drug delivery system.

Plant-based gold nanoparticles; a comprehensive review of the decade-long research on synthesis, mechanistic aspects and diverse applications

The worldwide focus on research in the field of green nanotechnology has resulted in the environmentally and biologically safe applications of a diversity of nanomaterials. Nanotechnology, in general, implies the production of nanoparticles having different but regular shapes, sizes, and properties. A lot of studies have been conducted on the synthesis of metal nanoparticles through biological, chemical, and physical methods. Owing to its safety, both environmental and in vivo, as well as the ease of synthesis, biogenic routes especially the plant-based synthesis of metal nanoparticles has been preferred as the best strategy. Among the metal nanoparticles, gold nanoparticles are recognized as the most potent, biocompatible and environment-friendly. A decade of research work has attempted the production of gold nanoparticles mediated by different parts of various plants. Further, these nanoparticles have been engineered through modification in the sizes and shapes for attaining enhanced activity and optimal performance in many different applications including biomedical, antimicrobial, diagnostics and environmental applications. This article reviews the fabrication strategies for gold nanoparticles via plant-based routes and highlights the diversity of the applications of these materials in bio-nanotechnology. The review article also highlights the recent developments in the synthesis and optical properties of gold nanoparticles.

Carbon@polypyrrole nanotubes as a photosensitizer in laser phototherapy of Pseudomonas aeruginosa

Phototherapy has been offered as an alternative and promising antibacterial strategy to overcome the antibiotic resistance problem. This study evaluated the antibacterial and phototherapy effects of carbon nanotubes with a polypyrrole coating in a core@shell structure (CNTs@PPy) on Pseudomonas aeruginosa (P. aeruginosa). P. aeruginosa was treated with CNTs@PPy at different concentrations (50-500 μg mL^-1) in dark or laser light irradiation with a wavelength of 808 nm, a power density of 1000 mW cm^-2 for 20 min. Temperature increment, cell viability, formation of reactive oxygen species (ROS) and protein/nucleic acid leakage subsequent the P. aeruginosa treatment were evaluated. The results showed that near-infrared laser irradiation of CNTs@PPy caused to a temperature increment confirming the ability of powerful photokilling of P. aeruginosa in a photothermal route. On the other hand, while CNTs@PPy represented just a 30-50% P. aeruginosa killing rate in dark, laser irradiation of 250 and 500 μg mL^-1 concentrations of CNTs@PPy resulted in a ˜70% P. aeruginosa killing rate, along with significant ROS production into the medium and protein and nucleic acid leakage from P. aeruginosa. These later effects were assigned to a photodynamic route activity of CNTs@PPy upon laser irradiation. Therefore, CNTs@PPy acted as a photosensitizer in both photothermal and photodynamic therapies to present an enhanced bactericidal activity to annihilate and destroyed the gram-negative bacteria P. aeruginosa, a cause of many infectious diseases.

Biosynthesis and Characterization of Silver Nanoparticles Using Phoenix dactylifera Fruits Extract and their In Vitro Antimicrobial and Cytotoxic Effects

Background:

In this article, silver nanoparticles (AgNPs) were synthesized by the biological green technique, using the aqueous extracts obtained from fruits of Phoenix dactylifera (date palm). This method is simple, rapid, non-toxic, and sustainable, and substitutes for the conventional physical/chemical methods. The cytotoxic activities of AgNPs derived from date fruit extract have not been mentioned in the earlier studies.

Methods:

The biosynthesized AgNPs are analyzed by Fourier transform infrared spectroscopy (FT-IR), UV-visible spectroscopy (UV-vis), and Transmission Electron Microscopy (TEM) methods. The assessment of antimicrobial effect towards human pathogenic microbial strains and their potential cytotoxicity against human breast cancer cell lines (MCF-7) were also evaluated.

Results:

FT-IR spectral studies showed that phytomolecules such as carbohydrates, phenolic acids and flavonoids present in date fruits extract are involved in the reduction and capping of the AgNPs. UV-vis spectrum revealed Surface Plasmon Resonance (SPR) at 425 nm which attributes the presence of AgNPs in aqueous extract. TEM micrographs showed that AgNPs particle diameter is ranged from 20 nm to 100 nm with spherical morphology. The biosynthesized AgNPs exhibited significant antimicrobial activity towards human microbial strains. Phytosynthesized NPs also induce cytotoxicity via necrosis, apoptosis and mitodepressive mechanisms that can disturb the cellular components at various stages of cell cycle.

Conclusion:

The present study concludes that biologically synthesized AgNPs using Phoenix dactylifera is cost-effective, rapid, non-toxic, and sustainable and can be effectively used as an adjunct for the treatment of breast carcinoma.

Green gold nanoparticles from plant-derived materials: an overview of the reaction synthesis types, conditions, and applications

Many studies have examined metallic nanoparticles (NPs) produced according to the principles of green chemistry. Gold NPs have drawn much more attention than other metallic NPs in recent years. Moreover, among all gold NP synthesis studies, using plant-derived molecules is one of the commonly used reductants in studies on NP synthesis because of its convenience in terms of shape, size control advantage, and nontoxic specifications. The present review focused on studies of the synthesis of gold NP types, including single gold atom NPs, alloyed AU NPs, and core-shell Au NPs as well as their conditions and applications. The effect of those structures on application fields such as catalysis, antifungal action, antibacterial activities, sensors and so on are also summarized. Furthermore, the morphology and synthesis conditions of the primer and secondary NP were discussed. In addition to synthesis methods, characterization methods were analyzed in the context of the considerable diversity of the reducing agents used. As the reducing agents used in most studies, polyphenols and proteins usually play an active role. Finally, the challenges and drawbacks in plant-derived agent usage for the preparation of Au NPs at various industries were also discussed.

Resonant Terahertz Light Absorption by Virtue of Tunable Hybrid Interface Phonon–Plasmon Modes in Semiconductor Nanoshells

Metallic nanoshells have proven to be particularly versatile, with applications in biomedical imaging and surface-enhanced Raman spectroscopy. Here, we theoretically demonstrate that hybrid phonon-plasmon modes in semiconductor nanoshells offer similar advantages in the terahertz regime. We show that, depending on tm,n,nhe doping of the semiconductor shells, terahertz light absorption in these nanostructures can be resonantly enhanced due to the strong coupling between interface plasmons and phonons. A threefold to fourfold increase in the absorption peak intensity was achieved at specific values of electron concentration. Doping, as well as adapting the nanoshell radius, allowed for fine-tuning of the absorption peak frequencies.

The Phosphorylation of IRS1S307 and AktS473 Molecules in Insulin-Resistant C2C12 Cells Induced with Palmitate Is Influenced by Epigallocatechin Gallate from Green Tea

In the current investigation, the effect of epigallocatechin gallate (EGCG) on the phosphorylation of IRS1^S307 and Akt^S473 molecules in insulin-resistant C2C12 muscle cells induced with palmitate was studied and compared with the effect of the antidiabetic drug, rosiglitazone. C2C12 myoblasts were cultured in Dulbecco's modified Eagle's medium and differentiated into myotubes using horse serum and the creatine kinase test was used to confirm their differentiation. The treatment of C2C12 myotubes was carried out with palmitate, where albumin was used as the conjugator. The Western blot technique was used to check the useful phosphorylation of IRS1^S307 and Akt^S473 in C2C12 myotubes, in the presence or absence of palmitate. There was a significant (p < 0.00) and linear increase in the activity of creatine kinase over time (0 to 96 h after differentiation) with everyday myoblast formation. While neither EGCG nor rosiglitazone showed a significant (p > 0.05) effect on palmitate content during 96 h of incubation of IRS1^S307 , EGCG alone or combined with rosiglitazone increased the phosphorylation of Akt^S473 , leading to the increase of glucose uptake into C2C12 cells. Thus, it can be concluded that EGCG alone or in combination with rosiglitazone may show some therapeutic effects for the prevention or treatment of Type 2 diabetes owing to its substantial effect on increasing the phosphorylation of Akt^S473 and the subsequent glucose uptake into the cells.

Investigation of ZnO nanoparticles on proline, anthocyanin contents and photosynthetic pigments and lipid peroxidation in the soybean

The interaction between nanoparticles and plants is inevitable. In this study, the effect of different concentrations of ZnO nanoparticles synthesised using olive extract on the soybean was studied. The soybean seeds were cultured in a Hoagland medium containing agar which was treated different concentrations (0, 200 and 400 ppm) of ZnO nanoparticles. After 21 days, the plants were harvested and the parameters of proline, anthocyanin, malondialdehyde (MDA), hydrogen peroxide (H2O2), chlorophyll and carotenoid contents and phenylalanine ammonia-lyase (PAL) and catalase (CAT) activity in soybeans (Glycine max) were measured. The results showed that the levels of chlorophyll a and b and carotenoid at concentrations of 200 and 400 ppm in comparison with control decreased, while carotenoid content at 200 ppm concentration at a concentration of 400 ppm was not significant. The level of anthocyanin and PAL activity increased with increasing concentration of nanoparticles, while proline content decreased. By increasing the concentration of ZnO nanoparticles, the content of MDA and hydrogen peroxide increased compared to control but CAT activity did not change significantly. This research suggests that ZnO nanoparticles synthesised using olive extract in soybean plants may be toxic by reactive oxygen species production.

Comparative study of antifungal effect of green and chemically synthesised silver nanoparticles in combination with carbendazim, mancozeb, and thiram

This study reports synthesis and characterisation of silver nanoparticles and their effect on antifungal efficacy of common agricultural fungicides. Silver nanoparticles were synthesised using biological and chemical reduction methods employing Elettaria cardamomum leaf extract and sodium citrate, respectively. Nanoparticles were then characterised using UV-Visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy, and dynamic light scattering (DLS). While XRD assigned particles size of 31.86 nm for green and 41.91 nm for chemical silver nanoparticles with the help of the Debye-Scherrer formula, DLS specified monodisperse nature of both suspensions. Nanoparticles were tested individually and in combination with fungicides (carbendazim, mancozeb, and thiram) against fungal phytopathogens. Silver nanoparticles exhibited good antifungal activity and minimum inhibitory concentration (MIC) was observed in the range of 8-64 µg/ml. Also, they positively influenced the efficacy of fungicides. The mean MIC value (mean ± SD) for combination of all three fungicides with green AgNPs was 1.37 ± 0.6 µg/ml and for chemical AgNPs was 1.73 ± 1.0 µg/ml. Hence, it could be concluded that green AgNPs performed better than chemical AgNPs. Synergy was observed between green AgNPs and fungicides against Fusarium oxysporum. In conclusion, this study reports synthesis of monodisperse silver nanoparticles which serve as efficient antifungal agents and also enhance the fungicidal action of reported agricultural fungicides in combination studies.

Antifungal and antibacterial activity of densely dispersed silver nanospheres with homogeneity size which synthesized using chicory: An in vitro study

With increase in isolation of multi and extensive drug resistance hospital pathogens (MDR, XDR) in burn centers of many hospitals in the world, attempt to use nanomaterials for treatment of burn-infected patients is the focus of researches all around the world. In the present investigation silver nanospheres (Ag NSs) has been synthesized by chicory seed exudates (CSE). The various parameters influencing the mechanism of Ag NSs synthesis including temperature, concentration, pH and time were studied. Greener Ag NSs were formed when the reaction conditions were altered with respect to pH, concentration of AgNO3 and incubation temperature. Finally, we evaluated antimicrobial activity of silver nanospheres biosynthesized by chicory (Cichodrium intybus) against most prevalent burn bacteria pathogens Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and fungus Fusarium solani. The UV visible spectroscopy, X-Ray diffraction (XRD), dynamic light scattering (DLS) used for primary screening of physicochemical properties. The transmission electron microscopy (TEM) images showed the Ag NSs (with globular shape) with a size less than 25nm that they have the same size about 8nm (more than 97% are 8nm). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Ag NSs against the standard strains of A. baumannii, P. aeruginosa and K. pneumonia showed a relatively high inhibitory and bactericidal activity (MIC 1.56μg/mL and MBC 3.12μg/mL) of the nanoparticles and F. solani cultures. In antifungal tests, the lowest level of zone of inhibition was observed at a concentration of 5μg/mL synthesized silver nanospheres with the 7% inhibition of growth. Ag NSs have high antimicrobial activity against three common burn bacteria pathogens and fungus F. solani. Therefore, Ag NSs can be used to prevent burn infection and for wound healing.

Green synthesis of labeled CeO2 nanoparticles with 99mTc and its biodistribution evaluation in mice

AIMS

The in vivo targeted diagnostic applications of biosynthetic Cerium oxide nanoparticles (CeO₂-NPs), prepared by applying chitosan as a stabilizer, was explored by evaluating the cytotoxicity through MTT assay on WEHI 164 cell line, the Hemolytic activity of CeO₂-NPs and biodistribution in rats.

MAIN METHODS

The CeO₂-NPs were characterized through the use of TGA/DTG, PXRD, FESEM, FTIR, and UV-Vis spectroscopy. The biodistribution of CeO₂-NPs were determined by directly labeled nanoparticles with Technetium-99 m (99mTc) radioisotope (99mTc-CeO₂-NPs). The labeling efficiency and stability of 99mTc-CeO₂-NPs were also measured with Instant Thin Layer Chromatography (ITLC) method. The saturation study was investigated by 1 mCi of 99mTc-CeO₂-NPs using different concentrations of WEHI 164 cells after 4 h of incubation. In vivo biodistribution study was performed by intravenous injection of 600 μCi/200 μL 99mTc-CeO₂-NPs through rat's tail.

KEY FINDINGS

CeO₂-NPs seemed to have a low cytotoxic effect on WEHI 164 cell line and did not result in hemolysis. The biodistribution of CeO₂-NPs has shown that a huge amount of 99mTc-CeO₂-NPs was amassed in the living human organs, including liver, lung, spleen, stomach, and thyroid which shows the in vivo stability of the labeled conjugate. Herein, we have developed a facile, economical, and greener synthetic procedure applying Chitosan template. This green approach is comparable to conventional methods that utilize hazardous materials which are would be a suitable alternative to circumvent synthetic issues related to these materials.

SIGNIFICANCE

The bio-applications of nano-sized CeO₂-NPs were explored to find new horizon to use nanotechnology as the diagnostic tool.

Biosynthesis of bimetallic and core-shell nanoparticles: their biomedical applications - a review

Recently, researchers succeeded in designing and manufacturing a new class of nanoparticles (NPs) called hybrid NPs. Among hybrid NPs, bimetallic and core-shell NPs were a revolutionary step in NPs science. A large number of green physiochemical and methods for nanostructures synthesis have been published. Eventually, physiochemical methods are either expensive or require the use of chemical compounds for the synthesis of bimetallic and core-shell nanostructures. The main challenges that scientists are facing are making the process cheaper, facile and eco-friendly efficient synthesis process. Green synthesis (biosynthesis) refers to the use of bio-resources (such as bacteria, fungi, plants or their derivatives) for the synthesis of nanostructures. The popularity of the green synthesis of nanostructures is due to their environmental friendliness and no usage of toxic materials, environmental friendliness for the synthesis or stability of nanostructure. Bimetallic and core-shell NPs have many biomedical applications such as removing heavy metals, parasitology, molecular and microbial sensor, gene carrier, single bacterial detection, oligonucleotide detection and so on. The purpose of this study is to discuss briefly the biosynthesised bimetallic and core-shell NPs, their biomedical applications.

Plant extracts as green reductants for the synthesis of silver nanoparticles: lessons from chemical synthesis

From conventional synthesis to green transformations: a brief literature overview and insight for the synthesis of Ag nanoparticles.