Poly(1-vinylimidazole) Prospects in Gene Delivery

Polymeric amines are being studied intensively as components of systems for gene delivery in genetic engineering and gene therapy of genetic disorders, including cancer. Despite remarkable achievements in the field, polymeric amines, such as polyethyleneimine, show some disadvantages. Strong interaction between the amine-containing polymer and nucleic acid hampers the release of nucleic acid in the cell cytoplasm. Amine groups can interact with the cell membrane which results in cell death. These limitations of polymeric amines stimulated an investigation of new structures for gene delivery. Imidazole-containing polymers have attracted attention as lesser basic substances, while they are able to interact with polymeric acids. Further development of imidazole-based gene delivery agents requires knowledge about some fundamental aspects of interaction between nucleic acids, and polymeric imidazoles. In this work, we studied the complexation of poly(1-vinylimidazole) and oligomeric DNA. We found that the number of active sites capable of binding with negatively charged phosphate groups is comparable with the number of protonated imidazole units in the case of high molecular weight polymer. The increase in polymer charge by 1-bromopropane quaternizating 1%?5% imidazole units or by decreasing the pH to 6.5?7 considerably increased the ability of poly(1-vinylimidazole) to interact with oligonucleotides. The pH sensitivity of this interaction is interesting for cancer gene therapy because the tumours have a lowered intercellular pH (stable oligonucleotide complex) and a higher extracellular pH which can lead to complex dissociation. Minimal critical length for complexation of quaternized poly(1-vinylimidazole) and DNA is below eight units which corresponds to polymers with amine groups. Fluorescence-tagged poly(1-vinylimidazole) samples were obtained and their potential for monitoring the polymer and polymer-oligonucleotide complex internalization into living cells was demonstrated.     

Nanotechnology,Green Synthesis and Biological Activity Application of Zinc Oxide Nanoparticles Incorporated Argemone Mxicana Leaf Extract

Nanomaterial is a rapidly growing area that is used to create a variety of new materials and nanotechnology applications from medical, pharmaceuticals, chemical, mechanical, electronics and several environmental industries including physical, chemical and biological nanoparticles are very important in our daily life. Nanoparticles with leaf extract from the healthy plant are important in the area of research using biosynthesis methods. Because of it’s used as an environmentally ecofriendly, other than traditional physical and chemical strategies. In particular, biologically synthesized nanoparticles have become a key branch of nanotechnology. The present work presents a synthesis of zinc oxide nanoparticles using an extract from the Argemone leaf Mexicana. Biosynthetic nanoparticles are characterized by X-ray diffraction (XRD), Ultraviolet visible (UV-vis) spectroscopy analysis, a Fourier Transform Infrared Spectroscopy analysis (FTIR) and a scanning electron microcopy (SEM), X-ray analysis with dispersive energy (EDAX). XRD is used to examine the crystalline size of zinc oxide nanoparticles. The FTIR test consists in providing evidence of the presence of targeted teams. UV is used for optical properties and calculates the energy of the bandwidth slot. The scanning microscope emission reveals the morphology of the surface and the energy dispersive X-ray analysis confirms the basic composition of zinc oxide nanoparticles. It is found that zinc nanoparticles are capable of achieving high anti-fungal efficacy and therefore have a high potential antimicrobial activity of ZnO NPs, like antibacterial and high antioxidant. Zinc Oxide nanoparticles from the Argemone Mexicana leaf extract have several antimicrobial applications, such as medical specialty, cosmetics, food, biotechnology, nano medicine and drug delivery system. ZnO nanoparticles are important because they provide many practical applications in industry. The most important use of nanoparticles of ZnO would be strong antibacterial and antioxidant activity with a simple and efficient biosynthesis method may be used for future work applications.     

Nanostructured ZnO thin film for hydrogen peroxide sensing

A thin film of zinc oxide (ZnO) was deposited over the surface of a glass substrate by spray pyrolysis technique. To obtain ZnO thin film with nano-grains in this process, the substrate temperature was optimized and fixed at 503 K. Zinc acetate dihydrate was used as a precursor at an optimal concentration of 0.05 M. The structural and morphological properties of the film were investigated using X-ray Diffraction (XRD) and Field Emission–Scanning Electron Microscopy (FE–SEM), respectively. The peaks in the XRD pattern, confirmed the polycrystalline nature of the film with hexagonal wurtzite structure. Purity of the film has been confirmed through Energy Dispersive X-ray analysis (EDAX). Further the sensing behavior of the film was studied for various concentrations of hydrogen peroxide (H₂O₂) at optimized operating temperatures of 323 and 373 K. The nanostructured ZnO film exhibited good sensitivity in the range of 500 and rapid response–recovery time of 30–60 s, respectively, towards lower concentrations of H₂O₂.     

Optical properties of melamine based materials

The melamine based crystalline materials are synthesized. To determine the optical properties the transmittance and reflectance spectra are recorded. The absorption coefficient of the materials is calculated using the recorded transmittance values. From the absorption coefficient values the insulating behavior of all our studied materials is identified. In addition the direct bandgap transition nature of the materials is recognized from the absorption coefficient value. Tauc relation is used to determine the bandgap energy. The bandgap energy values suggest the dielectric nature of the materials and interpretation is given for high dielectric constant values.     

Solvent-free protocol for amide bond formation via trapping of nascent phosphazenes with carboxylic acids

A solvent-free synthesis of amides via the coupling of phosphazenes with carboxylic acids is reported. Increasing the rate of heating either by microwave irradiation or conventional heating results in multifold increase in the rate of amide bond formation. Synthesis of a library of amides including a potent antitumour candidate has been accomplished.     

Catalytic oxidative conversion of alcohols, aldehydes and amines into nitriles using KI/I2-TBHP system

The oxidative conversion of alcohols, aldehydes and amines to give corresponding nitriles in excellent yields was easily achieved by the catalytic amount of KI or I₂ in combination with TBHP as an external oxidant. This non-transition metal catalyst is cost effective and provides easy work-up and separation of the product.     

Observation of subcellular structures of neurons by an illumination mode near-field optical microscope under an optical feedback control

We propose an illumination mode near-field optical microscope operated under an optical feedback for imaging biological specimens in their natural environment. For feedback control, rapidly varying evanescent signal has been generated over the sample surface. It has been found that evanescent signal can be profitably used as a control signal by utilizing its sample feature dependent discrimination sensitivity. Neurons have been successfully observed both in air and in liquid with a resolution well beyond the diffraction limit.     

Extraction chromatographic method for the separation of actinides and lanthanides using EDHBA grafted AXAD-16 polymer

A new extraction chromatographic method has been developed by grafting chloromethylated polymer support with 4-ethoxy-N,N-dihexylbutanamide (EDHBA), for the selective extraction of U(VI), Th(IV), La(III) and Nd(III) from highly acidic matrices. The developed grafted polymer has been characterized using ¹³C-CPMAS NMR spectroscopy, FT-NIR spectroscopy and also by CHN elemental analysis. The water regaining capacity of the grafted polymer is studied by TGA measurements and the active participation of the amide moiety towards metal ion complexation has been confirmed by Far IR spectroscopy. For the quantitative extraction of metal ions to the resin phase, various physio-chemical parameters are optimized by both static and dynamic methods. The developed amide grafted polymeric matrix shows good distribution ratio values even at high acidities, with the maximum metal sorption capacity values being 0.36, 0.69, 0.32 and 0.42 mmol g⁻¹ for U(VI), Th(IV), La(III) and Nd(III), respectively, at 6 M HNO₃ medium. The kinetics of metal ion phase equilibration is found to be moderately fast, with t_1/2 values of <6 min, for all the analytes of interest. The limits of analyte quantification (LOQ) using the developed method are in the range of 15-30 μg L⁻¹. Moreover, the sequential separation of the sorbed actinides and lanthanides could be achieved by first eluting with 100 mL of distilled water (for actinides) followed by elution with 20 mL of 0.1 M EDTA (for lanthanides). The selectivity behavior and the practical applicability of the developed resin are tested using synthetic low level nuclear reprocessing mixtures and also with monazite sand. The analytical data are within 3.8% relative standard deviation, reflecting the reproducibility and reliability of the developed method.