Templated Techniques for the Synthesis and Assembly of Plasmonic Nanostructures

A two-step ligand-exchange strategy is developed, in which the long-carbon- chain ligands on all-inorganic perovskite (CsPbX3 , X = Br, Cl) quantum dots (QDs) are replaced with halide-ion-pair ligands. Green and blue light-emitting diodes made from the halide-ion-pair-capped quantum dots exhibit high external quantum efficiencies compared with the untreated QDs.

Highly Efficient Perovskite-Quantum-Dot Light-Emitting Diodes by Surface Engineering

Metal nanoparticles have been the subject of widespread research over the past two decades. In recent years, noble metals have been the focus of numerous studies involving synthesis, characterization, and applications. Synthesis of an impressive range of noble metal nanoparticles with varied morphologies has been reported. Researchers have made a great progress in learning how to engineer materials on a nanometer length scale that has led to the understanding of the fundamental size- and shape-dependent properties of matter and to devising of new applications. In this article, we review the recent progress in the colloid-chemical synthesis of nonspherical nanoparticles of a few important noble metals (mainly Ag, Au, Pd, and Pt), highlighting the factors that influence the particle morphology and discussing the mechanisms behind the nonspherical shape evolution. The article attempts to present a thorough discussion of the basic principles as well as state-of-the-art morphology control in noble metal nanoparticles.

Nonspherical Noble Metal Nanoparticles: Colloid-Chemical Synthesis and Morphology Control

State of the art in gold nanoparticle synthesis

This review captures the synthesis, assembly, properties, and applications of copper chalcogenide NCs, which have achieved significant research interest in the last decade due to their compositional and structural versatility. The outstanding functional properties of these materials stems from the relationship between their band structure and defect concentration, including charge carrier concentration and electronic conductivity character, which consequently affects their optoelectronic, optical, and plasmonic properties. This, combined with several metastable crystal phases and stoichiometries and the low energy of formation of defects, makes the reproducible synthesis of these materials, with tunable parameters, remarkable. Further to this, the review captures the progress of the hierarchical assembly of these NCs, which bridges the link between their discrete and collective properties. Their ubiquitous application set has cross-cut energy conversion (photovoltaics, photocatalysis, thermoelectrics), en...

Compound Copper Chalcogenide Nanocrystals

Anethum graveolens Linn., Foeniculum vulgare Mill. and Trachyspermum ammi L. are widely used traditional medicinal plants to treat various ailments. To provide a scientific basis to traditional uses of these plants, their aqueous and organic seed extracts, as well as isolated phytoconstituents were evaluated for their antibacterial potential. Antibacterial activity of aqueous and organic seed extracts was assessed using agar diffusion assay, minimum inhibitory concentration and viable cell count studies; and their antibacterial effect was compared with some standard antibiotics. The presence of major phytoconstituents was detected qualitatively and quantitatively. The isolated phytoconstituents were subjected to disc diffusion assay to ascertain their antibacterial effect. Hot water and acetone seed extracts showed considerably good antibacterial activity against all the bacteria except Klebsiella pneumoniae and one strain of Pseudomonas aeruginosa. Minimum inhibitory concentration for aqueous and acetone seed extracts ranged from 20–80 mg/ml and 5–15 mg/ml respectively. Viable cell count studies revealed the bactericidal nature of the seed extracts. Statistical analysis proved the better/equal efficacy of some of these seed extracts as compared to standard antibiotics. Phytochemical analysis showed the presence of 2.80 – 4.23% alkaloids, 8.58 – 15.06% flavonoids, 19.71 – 27.77% tannins, 0.55–0.70% saponins and cardiac glycosides. Antibacterial efficacy shown by these plants provides a scientific basis and thus, validates their traditional uses as homemade remedies. Isolation and purification of different phytochemicals may further yield significant antibacterial agents.

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Antibacterial and phytochemical screening of Anethum graveolens, Foeniculum vulgare and Trachyspermum ammi

Aqueous extracts of ten medicinal plants were examined for their antibacterial potential against some reference strains of human pathogenic bacteria. Anethum graveolens, Elettaria cardamomum, Foeniculum vulgare, Trachyspermum ammi and Viola odorata were found to be better/equally effective compared to standard antibiotics. V. odorata was the most effective antibacterial with minimum inhibitory concentration values ranging from 1 to 2%. The results provide a scientific basis for the centuries-old usage of aqueous extracts of these medicinal plants.

Antibacterial activity of some Indian medicinal plants

Bovine serum albumin (BSA) conjugated gold (Au) nanoparticles (NPs) were synthesized to explore their applications as drug delivery vehicles in systemic circulation. They showed little hemolysis and cytotoxic responses essentially required for such applications. This study shows some of the important physiochemical aspects needed for an appropriate synthesis of BSA-conjugated NPs where unfolded BSA is an essential reaction component. Unfolding of BSA was carried out under different experimental conditions in the presence of different ionic/zwitterionic surfactants and monitored simultaneously by UV–visible studies. Cationic surfactants induced unfolding at relatively lower temperatures than anionic and zwitterionic surfactants due to stronger electrostatic interactions with BSA. TEM analysis revealed the presence of NPs with almost similar shapes and sizes for different samples, and all NPs were stabilized by a coating of unfolded BSA. Isoelectric point of unfolded BSA coating on NP surface was close to 4...

Bovine Serum Albumin Bioconjugated Gold Nanoparticles: Synthesis, Hemolysis, and Cytotoxicity toward Cancer Cell Lines

Emerging antibiotic resistance is a worldwide problem that has led to the need for development of novel antimicrobials. Evaluation of natural products as safe and effective antimicrobial agents is one of the scientific strategies to combat the menace of drug-resistant pathogens. Natural products are in use for the treatment of infectious diseases since times immemorial and plants have been an integral part of traditional medicinal system all over the world. Recent years have witnessed a renewed interest in homemade remedies as an impressive number of modern drugs have been developed from plants. The objective of this review is to provide a consolidated report on traditional uses and biological activities of three medicinal plants viz. Anethum graveolens, Foeniculum vulgareand Trachyspermum ammi which have been extensively used for gastrointestinal disorders.

	 

	Key words: Antimicrobials, bioactivity, Anethum graveolens, Foeniculum vulgare, medicinal plants, Trachyspermum ammi.

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Bioactive potential of Anethum graveolens, Foeniculum vulgare and Trachyspermum ammi belonging to the family Umbelliferae - current status.

A seed-mediated approach was applied to synthesize gold (Au) nanoparticles (NP) by using twin tail alkylammonium cationic surfactants such as 12-6-12 and 12-0-12 as capping agents in aqueous phase at ambient conditions. The growth of Au NP was monitored by changing the amount of seed. Spherical NP (10–50nm) and nanorods (aspect ratio = 2–3) were obtained in the presence of 12-6-12 as capping agent; their shape and size systematically deformed because of anisotropic growth with a decrease in the amount of seed. In contrast, when 12-0-12 was used as a capping agent, no anisotropic growth was observed. An effective liquid/solid interfacial adsorption of 12-0-12 prevented anisotropic growth which led to precise morphologies. This was not observed in the case of 12-6-12 because of the presence of a spacer which restricted an effective interfacial adsorption because of the steric factors. XPS and FTIR studies clearly indicated the presence of a surfactant film on the surface of Au NP, while XRD analysis demonst...

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Gurinder Kaur

Papers

Antibacterial and phytochemical screening of Anethum graveolens, Foeniculum vulgare and Trachyspermum ammi

Antibacterial activity of some Indian medicinal plants

Bovine Serum Albumin Bioconjugated Gold Nanoparticles: Synthesis, Hemolysis, and Cytotoxicity toward Cancer Cell Lines

Bioactive potential of Anethum graveolens, Foeniculum vulgare and Trachyspermum ammi belonging to the family Umbelliferae - current status.

Dependence of Crystal Growth of Gold Nanoparticles on the Capping Behavior of Surfactant at Ambient Conditions