Synthesis of pectin-N,N-dimethyl acrylamide hydrogel by gamma radiation and application in drug delivery (in vitro)

The objective of the work is to synthesize pectin-N, N-Dimethylacrylamide (DMAA) hydrogel by gamma radiation without using any initiators and cross-linking agents. Effect of radiation doses on gel fraction and equilibrium swelling as a function of pH were studied, and 5 kGy radiation dose was found to be the optimum dose for hydrogel synthesis. The grafting /crosslinking was investigated by Fourier transform infrared spectroscopy. Thermal properties and surface morphology were studied by differential scanning calorimetry and scanning electron microscopy. To study the drug release kinetics, 5-fluorouracil was loaded into the hydrogel and in vitro release was carried out in simulated gastric and intestinal fluid. The release profile of drug showed that more than 90% of the loaded drugs were released after 4 hours at both gastric fluid and intestinal fluid pH. Drug release data was fitted into zero order, Higuchi and Korsmeyer-Peppas kinetic models. Higuchi model was found to be the best fitted and release exponent ‘n’ value of Korsmeyer-Peppas model indicated the non-Fickian transport.     

Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium oxysporum

The development of reliable, eco-friendly processes for the synthesis of nanomaterials is an important aspect of nanotechnology today. One approach that shows immense potential is based on the biosynthesis of nanoparticles using biological micro-organisms such as bacteria. In this laboratory, we have concentrated on the use of fungi in the intracellular production of metal nanoparticles. As part of our investigation, we have observed that aqueous silver ions when exposed to the fungus Fusarium oxysporum are reduced in solution, thereby leading to the formation of an extremely stable silver hydrosol. The silver nanoparticles are in the range of 5–15 nm in dimensions and are stabilized in solution by proteins secreted by the fungus. It is believed that the reduction of the metal ions occurs by an enzymatic process, thus creating the possibility of developing a rational, fungal-based method for the synthesis of nanomaterials over a range of chemical compositions, which is currently not possible by other microbe-based methods.     

Thermodynamic and micellization studies of a cationic gemini surfactant 16-6-16: Influence of ascorbic acid and temperature

Herein, we report the study of the influence of ascorbic acid and temperature on the micellization of a cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide), 16-6-16. The critical micelle concentration (CMC) of 16-6-16 was measured by the conductivity method and dye solubilisation technique. A tendency of the CMC values to increase with temperature and upon the adding of ascorbic acid was found. The standard Gibbs energy, standard enthalpy, and standard entropy of micellization of 16-6-16 were evaluated. The results of calculations suggest the decrease of the stability of the 16-6-16 micellar solution in the presence of ascorbic acid.     

Performance of a Gyratory Square-Shaped Capacitive Radio Frequency Discharge Plasma Sputtering Source for Materials Processing

We proposed a gyratory square-shaped capacitive radio-frequency discharge plasma sputtering source for materials processing and functional film preparation, composed of magnet arrangements consisting of eight neodymium bar magnets of dimensions 30 mm × 5 mm × 3 mm. In order to evaluate its performance, two square-shaped magnetic arrangements were investigated: case (a) without iron shielding and case (b) with iron shielding of dimensions 5 mm × 3 mm × 1 mm. The magnetic field simulation is analyzed, while the plasma discharge characteristics and the film properties are measured. The film thickness and the resistivity profiles of case (b) are more uniform than their corresponding profiles in case (a). The lowest electrical resistivity of the film is 4.33 × 10^?8 Ω m at r = 30 mm for case (b), which is of the same order as the bulk resistivity of the copper. The roughnesses of the film thickness profile for cases (a) and (b) are ±24.4 and ±7.2%, respectively. Using atomic force microscopy analysis, the film surface for case (b) was observed to show an improved smooth surface with reduced needle-shaped grain size and a lower surface roughness than that of case (a). The surface roughness of the films is approximately 3.73 and 2.49 nm for case (a) and case (b), respectively. From the X-ray diffraction patterns, the film texture, the relative intensity ratios of the (111) peak to the (200) [I₍₁₁₁₎/ I₍₂₀₀₎] were found to be 13.76 and 4.08 for the cases (a) and (b), respectively.