Assessment of antimicrobial activity of chitosan/silver nanoparticles hydrogel and cryogel microspheres.

This research investigates the synthesis and characterization of hydrogel and cryogel microspheres that are doped with green synthesised silver nanoparticles (CS-AgNPs). Also, the study assesses the antibacterial activity of hydrogel and cryogel microspheres by comparing them with commercial antibiotics. The porous structure of CS and the adequate dispersion of AgNPs were confirmed by SEM and EDX techniques, respectively. The disk diffusion method and the optical density measurement (OD600) confirm the outstanding antimicrobial activity of CS-AgNPs hydrogel and cryogel microspheres in comparison to antibiotics for both Gram-positive and Gram-negative bacteria. The CS-AgNPs microspheres demonstrate promising antimicrobial and biocompatible agents for medical field applications.

In vitro scolicidal activity of synthesised silver nanoparticles from aqueous plant extract against Echinococcus granulosus.

At present, biosynthesis of AgNPs is a very effective method to produce less toxic nanoparticles. The vision of this research is to use three different plant extracts derived from leaves of Piper nigrum, Ziziphus Spina-Christi and Eucalyptus globulus for rapid biosynthesis of AgNPs. This is in addition to investigating the scolicidal activity against Echinococcus granulosus. The methods of UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX) were employed to characterise the nanoparticles. UV spectra disclosed a maximum absorption at 437 nm for the biosynthesised AgNPs using EUCGLO extract. The XRD patterns revealed the (fcc) structure of the AgNPs with slightly shifted characteristic peaks at 2θ degree of 37.3˚ and 43.4˚, respectively. The scolicidal activity against E. granulosus revealed that the AgNPs, which were synthesised using Eucalyptus globulus, have powered scolicidal of 47.8 % after 45 min. which is comparable to the treatment by Albendazole.

Morphology control of nickel nanoparticles prepared in situ within silica aerogels produced by novel ambient pressure drying.

Silica aerogels are low density solids with high surface area and high porosity which are ideal supports for catalyst materials. The main challenge in aerogel production is the drying process, which must remove liquid from the pores of the wet gel while maintaining the solid network. In this work, the synthesis of silica aerogels and nickel-doped silica aerogels by a low energy budget process is demonstrated. Silica aerogels are produced by ambient drying using ammonium bicarbonate, rather than a conventional low surface tension solvent. Heating dissociates the ammonium bicarbonate, so generating CO2 and NH3 within the pores of the wet gel which prevents pore collapse during drying. Nickel-doped aerogels were produced by reducing nickel ions within pre-synthesised silica aerogels. The morphology of the resulting nickel particles-spheres, wires and chains-could be controlled through an appropriate choice of synthesis conditions. Materials were characterized using nitrogen adsorption/desorption isotherms, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis and X-ray diffraction. The surface area of undoped aerogel is found to increase with the concentration of ammonium bicarbonate salts from 360 to 530 m2 g-1, and that of nickel-doped silica aerogel varies from 240 to 310 m2 g-1 with nickel doping conditions.

Bioinspired Synthesis of Monolithic and Layered Aerogels.

Aerogels are the least dense and most porous materials known to man, with potential applications from lightweight superinsulators to smart energy materials. To date their use has been seriously hampered by their synthesis methods, which are laborious and expensive. Taking inspiration from the life cycle of the damselfly, a novel ambient pressure-drying approach is demonstrated in which instead of employing low-surface-tension organic solvents to prevent pore collapse during drying, sodium bicarbonate solution is used to generate pore-supporting carbon dioxide in situ, significantly reducing energy, time, and cost in aerogel production. The generic applicability of this readily scalable new approach is demonstrated through the production of granules, monoliths, and layered solids with a number of precursor materials.

Synthesis and Characterisation of Reduced Graphene Oxide/Bismuth Composite for Electrodes in Electrochemical Energy Storage Devices.

A reduced graphene oxide/bismuth (rGO/Bi) composite was synthesized for the first time using a polyol process at a low reaction temperature and with a short reaction time (60 °C and 3 hours, respectively). The as-prepared sample is structured with 20-50 nm diameter bismuth particles distributed on the rGO sheets. The rGO/Bi composite displays a combination of capacitive and battery-like charge storage, achieving a specific capacity value of 773 C g-1 at a current density of 0.2 A g-1 when charged to 1 V. The material not only has good power density but also shows moderate stability in cycling tests with current densities as high as 5 A g-1 . The relatively high abundance and low price of bismuth make this rGO/Bi material a promising candidate for use in electrode materials in future energy storage devices.