Green biosynthesis of gold nanoparticles using Croton sparsiflorus leaves extract and evaluation of UV protection,antibacterial and anticancer applications

Our study reports greener synthesis of gold nanoparticles (AuNPs) tethered to the extract of Croton sparsiflorus and in vitro evaluation of UV-protection, antibacterial and anticancer activities. Sophisticated instrumental analytical techniques such as UV–vis spectrophotometer, FT-IR, XRD, FE-SEM, and TEM were employed for the existence and confirmation of the nanoparticles. FT-IR and HPLC analysis were executed in the identification of the plausible functional groups implicated in the reduction of gold ions to AuNPs. UV protection property and antibacterial action of AuNPs-coated cotton fabric were also presented. Moreover, in vitro anticancer evaluation against HepG2 cell line was conducted by MTT assay for Croton sparsiflorus extract derived AuNPs in different concentrations (50 to 150 μg/ml). Thus, the results of this work revealed that greener synthesized AuNPs exhibited good therapeutic applications as UV-protection, antibacterial and anticancer agents.     

Concurrent genesis of color and electrical conductivity in leathers through in‐situ polymerization of aniline for smart product applications

We present a simple method to produce self‐colored and conducting leathers using in‐situ polymerization of aniline with ammonium persulfate as oxidant and hydrochloric acid as dopant. The structural and morphological features of treated leathers were examined using Fourier transformed infra‐red spectroscopy, X‐ray diffraction and scanning electron microscopic analyses. Results suggest the deposition of conducting emeraldine salt form of polyaniline on the leather substrate rather than other poorly conducting states. We also show that the treated leathers are bluish green through reflectance measurements thereby suggesting that the use of toxic and expensive dyes can be avoided for coloration process. Further, we demonstrate that a maximum electrical conductivity of 0.15 S/cm is obtained for the leather treated with optimal experimental conditions, which aids its application to operate touch‐screen devices. Copyright © 2015 John Wiley & Sons, Ltd.     

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

Compounds containing oxygen, nitrogen, or sulfur atoms inside the rings are attracting much attention and interest due to their biological importance. In recent years, several methods for the synthesis of such molecules have been reported by using aldo‐X bifunctional building blocks (AXB3 s) as substrates; these are a wide class of organic molecules that contain at least two reactive sites, among them, one aldehyde, acetal, or semiacetal group was involved. Because of the multiple reactivities, AXB3 s are widely used in the one‐pot synthesis of biologically important heterocycles. This review summarizes the synthesis of important heterocycles by using AXB3 s as pivotal components in establishing multicomponent reactions, tandem reactions, and so forth. In many cases, the established reaction systems with AXB3 s were characterized by some green properties, such as easy access to the substrate, mild and environmentally benign conditions, and wide scope of the substrate.     

Li ion conduction in TiO2 filled polyvinylidenefluoride-co-hexafluoropropylene based novel nanocomposite polymer electrolyte membranes with LiDFOB

This paper describes, nanocomposite polymer electrolyte (NCPE) based on polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP), which comprises the novel lithium difluoro(oxalato)borate (LiDFOB). Ehtylene carbonate (EC) and diethyl carbonate (DEC) mixture was used as gelling agent and nanoparticulate TiO₂ used as filler. The NCPE membranes were subjected to a.c. impedance, tensile strength, Raman studies, TG/DTA and morphological studies. 5 wt% TiO₂ comprising membranes exhibited enhanced conductivity of 0.56 mS cm⁻¹and the Young’s modulus was increased from 1.32 to 2.74 MPa. The structural change of α to β phase was confirmed by Raman studies. The thermal stability of the NCPE membrane is found to be 130 °C. Calculation of activation energy and synthesis of LiDFOB has also been presented.     

Chemical approach to the realization of electronic devices in epitaxial graphene

We have shown that nitrophenyl groups may be added to the surface of few‐layer epitaxial graphene (EG) by the formation of covalent carbon–carbon bonds thereby changing the electronic structure and transport properties of EG from near‐metallic to semiconducting. In the present Letter we discuss the opportunities afforded by such chemical processes to engineer device functionality in graphene by modification of the electronic properties without physical patterning.

     

Synthesis and Antimicrobial Evaluation of 1,4-Naphthoquinone Derivatives as Potential Antibacterial Agents

1,4-Naphthoquinones are an important class of compounds present in a number of natural products. In this study, a new series of 1,4-naphthoquinone derivatives were synthesized. All the synthesized compounds were tested for in vitro antimicrobial activity. In this present investigation, two Gram-positive and five Gram-negative bacterial strains and one pathogenic yeast strain were used to determine the antibacterial activity. Naphthoquinones tested for its antibacterial potencies, among seven of them displayed better antimicrobial activity against Staphylococcus aureus (S. aureus; 30–70 μg/mL). Some of the tested compounds showed moderate to low antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) and Salmonella bongori (S. bongori; 70–150 μg/mL). In addition, most active compounds against S. aureus were evaluated for toxicity to human blood cells using a hemolysis assay. For better understanding, reactive oxygen species (ROS) generation, time-kill kinetic study, and apoptosis, necrosis responses were investigated for three representative compounds.     

Some ABO3 oxides with defect pyrochlore structure

Studies on the formation, structures and properties of the ternary oxides TlNbO₃, TlTaO₃ and BiVO_3+x occurring in A₂B₂O_7-y defect pyrochlore structure are reported. The reaction of Tl₂ CO₃ with Nb₂O₅/Ta₂O₅ initially leads to the formation of TlNbO_3+x [x ～ 0.3] and TlTaO_3+x [x ～ 0.4]. On further heating, the phases lose oxygen forming TlTaO₃ and TlNbO₃. The occurrence of ABO₃ oxides having Tl⁺, Pb²⁺ or Bi³⁺ as the A cation in defect pyrochlore structure in preference to the perovskite structure is attributed to the formation of a “trap-mediated” A-A bond through 6s² electrons.     

Optical phase conjugation by degenerate four-wave mixing in basic green 1 dye-doped gelatin film using He–Ne laser

Optical phase conjugation in gelatin film doped with basic green 1 has been measured using CW laser radiation (λ=632.8 nm) generated by He–Ne laser of total power 35 mW. The degenerate four-wave mixing (DFWM) experiment allowed for measurement of phase conjugate reflectivity as a function of dye concentration, backward beam intensity, forward beam intensity, probe beam intensity, mean pumping beam intensity and angle between the forward pumping beam and probe beam. For 1 mM concentration of basic green 1-doped gelatin film, 0.1% phase conjugate reflectivity has been observed.     

Nanoscale surface modification via scanning electrochemical probe microscopy

Micro- and nanoscale surface modification using scanning probe microscopy techniques in combination with electrochemically induced surface structuring provides a maskless in situ fabrication strategy enabling deposition or etching of three-dimensional nanostructures. This current opinion article focuses on scanning electrochemical probe microscopy techniques highlighting recent progress in nanoscale 3D surface modification along with a spotlight on approaches of practical relevance.     

Cytotoxicity assessment of palbociclib-loaded chitosan-polypropylene glycol nano vehicles for cancer chemotherapy

The delivery of drugs in nanosized carriers arises as a very attractive solution. This study reports the in vitro cytotoxic effect of palbociclib loaded chitosan cross-linked polypropylene glycol nanocarriers. The nanocarriers were prepared by ion gelation using calcium chloride, calcium oxalate, and sodium tripolyphosphate as cross-linking agents. The influence of the cross-linking agent on the size and morphology of the chitosan- polypropylene glycol nanocarriers was studied by Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM), and Atomic Fluorescence Microscope (AFM). Tripolyphosphate assisted carriers was found higher amount palbociclib encapsulation capacity compared with other two carriers. The drug releasing behavior was studied at pH 6.8 which was based on the bulk erosion principal of the carriers. Palbociclib loaded chitosan-polypropylene glycol carriers were found to show excellent drug releasing kinetics and biocompatibility in in-vitro analysis. The unloaded chitosan-polypropylene glycol carrier was identified to have less inherent cytotoxicity, whereas the loaded carriers are as active as equal to pure palbociclib against the MCF-7 cancer cell line. The palbociclib loaded nanocarriers were studied to determine their potential anticancer activity against the MCF-7 cell line. The IC₅₀ values of three carriers chitosan-polypropylene glycol -I, chitosan-polypropylene glycol -II and chitosan-polypropylene glycol -III was observed 55.4, 51.0 and 38.7 mg/μL respectively. The effect of palbociclib uptake was evaluated by confocal microscopy using acridine orange/ethidium bromide and 4, 6-diamidino-2-phenylindole staining. Palbociclib loaded chitosan-polypropylene glycol nanocarriers show promise as potential candidates for cancer therapeutic applications.