Mn-Doped ZnSe Quantum Dots as Fluorimetric Mercury Sensor

Quantum dots (QDs), because of their exciting optical properties, have been explored as alternative fluorescent sensors to conventional organic fluorophores which are routinely employed for the detection of various analytes via fluorometry. QD probes can detect toxic metal ions, anions, organic molecules with good selectivity and sensitivity. This chapter investigates the synthesis of Mn-doped ZnSe QDs using nucleation-doping strategy. The as-synthesized QDs were characterized by various analytical tools such as ultraviolet-visible (UV-vis) absorption, photoluminescence (PL) spectroscopy, X-ray diffractometry (XRD) and transmission electron microscopy (TEM). It was found that Mn doping of QDs significantly increases the PL intensity. The PL of the resulting QDs was examined in the presence of different metal ions to check its selective response. Among the various metal ions, Hg2+ exhibits a drastic quenching of the QD’s emission intensity. A Stern-Volmer plot of [Hg2+] sensing using the as-synthesized QDs showed linearity in the range of 0–30 × 10−6 ML−1 with the regression coefficient R2 = 0.99. The detection limit was found to be 6.63 × 10−7 ML−1. Thus, the present Mn-doped ZnSe QDs represent a simple, non-toxic fluorescent probe for the qualitative and quantitative detection of mercury ions in aqueous samples

Piper nigrum

Utilization of biological materials in synthesis of nanoparticles is one of the hottest topics in modern nanoscience and nanotechnology. In the present investigation, the silver nanoparticles were synthesized by using the leaf and stem extract of Piper nigrum. The synthesized nanoparticle was characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray analysis (EDAX), and Fourier Transform Infrared Spectroscopy (FTIR). The observation of the peak at 460 nm in the UV-vis spectra for leaf- and stem-synthesized silver nanoparticles reveals the reduction of silver metal ions into silver nanoparticles. Further, XRD analysis has been carried out to confirm the crystalline nature of the synthesized silver nanoparticles. The TEM images show that the leaf- and stem-synthesized silver nanoparticles were within the size of about 7–50 nm and 9–30 nm, respectively. The FTIR analysis was performed to identify the possible functional groups involved in the synthesis of silver nanoparticles. Further, the antibacterial activity of the green-synthesized silver nanoparticles was examined against agricultural plant pathogens. The antibacterial property of silver nanoparticles is a beneficial application in the field of agricultural nanotechnology

Synthesis of silver nanoparticles and the antibacterial and anticancer activities of the crude extract of sargassum polycystum C. Agardh

The potential of the methanolic extract of the seaweed, Sargassum polycystum in the synthesis of silver nanoparticles was investigated. The extract synthesized appreciable quantities of silver nanoparticles of the size 5- 7 nm, in 24 hrs. The particles were characterized by UV-Vis, FT-IR spectroscopy, HRTEM and XRD analysis. The results indicated that the algal extract can be utilized as an eco-friendly system for the synthesis of silver nanoparticles for various applications in the field of medicine. The methanolic extract of the alga, silver nitrate solution and their combination were tested for their antimicrobial activities against Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus. Anticancer activity of the extract and the silver nanoparticles were evaluated against the breast cancer line MCF-7. Active compounds in the crude extract of the alga were separated and identified as fatty acids by GC-MS analysis. These fatty acids together with the silver nanoparticles exhibited anticancer activity against the breast cancer cell line MCF-7. Results are presented and discussed in detail

Novel copper doped Halloysite Nano Tube/silver-poly(pyrrole-co-3,4-ethylenedioxythiophene) dual layer coatings on low nickel stainless steel for anti-corrosion applications

The increase of the diverse and complicated applications of stainless steel in all fields of industry production and various research activities have induced immense efforts in research and fabrication to increase its efficiency and sophisticated to minimize its corrosion by using among others conducting polymer coatings. The present work discusses the corrosion resistant behavior of stainless steel with copolymer and composite dual layer coatings. The coated samples were analyzed by various analytical studies and the results are discussed. The dual layer composite coating Ag-p(Py-co-EDOT) thus obtained was uniform in nature and highly adherent to the stainless steel surface, when compared to the monolayer coatings. An antibacterial effect of coating and the coatings against marine and pathogenic bacteria have also been studied. Keywords: Dual layer coatings, Electrochemical studies, Surface analysis, Antibacterial activity, Ion leachout tes

Synthesis of Silver Nanorods from Food Industrial Waste and Their Application in Improving the Keeping Quality of Milk

A novel method for the synthesis of silver nanorods is reported, in which industrial milk waste was utilized, that were then used to extend the stability of milk. During the synthesis, the size of the silver nanorods were affected by pH and temperature. Silver nanorods were formed at alkaline pH in room temperature, whereas nanoparticles were formed in lower pH at elevated temperature. The obtained nanostructures were characterized by UV–visible spectrophotometer, energy dispersive X-ray analysis (EDAX), and transmission electron microscope (TEM). These silver nanorods were used to control coliform and standard plate count (SPC) in milk. This was confirmed by an increase in 4 to 5 folds of methylene blue reduction time as compared to the control. The Hom inactivation model was proposed to express microbial inactivation in milk. The cytotoxic effect of silver nanorods shows that they have been nontoxic to humans even at higher concentration

Palladium nanoparticle-decorated reduced graphene oxide sheets synthesized using Ficus carica fruit extract: A catalyst for Suzuki cross-coupling reactions

We present a biogenic method for the synthesis of palladium nanoparticle (PdNP)-modified by reducing graphene oxide sheets (rGO) in a one-pot strategy using Ficus carica fruit juice as the reducing agent. The synthesized material was well characterized by morphological and structural analyses, including, Ultraviolet-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Transmission Electron Microscopy (TEM) and Raman spectroscopy. The results revealed that the PdNP modified GO are spherical in shape and estimated to be a dimension of ~0.16 nm. The PdNP/graphene exhibits a great catalytic activity in Suzuki cross-coupling reactions for the synthesis of biaryl compounds with various substrates under both aqueous and aerobic conditions. The catalyst can be recovered easily and is suitable for repeated use because it retains its original catalytic activity. The PdNP/rGO catalyst synthesized by an eco-friendly protocol was used for the Suzuki coupling reactions. The method offers a mild and effective substitute to the existing methods and may significantly contribute to green chemistry

Additional file 1: Figure S1. of Shape- and Size-Controlled Synthesis of Silver Nanoparticles Using Aloe vera Plant Extract and Their Antimicrobial Activity

Comparison among inhibitions by AgNP (by chemical method), AgNP with Aloe vera plant extract, only Aloe vera plant extract and only AgNO3 solution. 1. Staphylococcus aureus; 2. Bacillus cereus; 3. Micrococcus luteus; 4. Escherichia coli; 5. Klebsiella pneumoniae. The values were determined based on statistical standard deviation with the triplicate values. The calculated standard deviations were between Âą1 and Âą2. (DOCX 84 kb

TEM images for recycling of PdNP/rGO.

<p>a) before and b) After five consecutive cycles. The degree of agglomeration of catalyst does not show the significant change between the first and the fifth runs.</p

Transmission electron microscopy images.

<p>(a-e) Images along with particle size distribution; (g) HRTEM image along with fringe spacing; and (f) SAED image of the PdNP/rGO.</p