Gum Arabic polymer-stabilized and Gamma rays-assisted synthesis of bimetallic silver-gold nanoparticles: Powerful antimicrobial and antibiofilm activities against pathogenic microbes isolated from diabetic foot patients.

In this research, irradiation by gamma rays was employed as an eco-friendly route for the construction of bimetallic silver-gold nanoparticles (Ag-Au NPs), while Gum Arabic polymer was used as a capping agent. Ag-Au NPs were characterized through UV-Vis., XRD, EDX, HR-TEM, FTIR, SEM/mapping and EDX analysis. Antibiofilm and antimicrobial activities were examined against some bacteria and Candida sp. isolates from diabetic foot patients. Our results revealed that the synthesis of Ag-Au NPs depended on the concentrations of tetra-chloroauric acid and silver nitrate. HR-TEM analysis confirmed the spherical nature and an average diameter of 18.58 nm. FTIR results assured many functional groups in Gum Arabic which assisted in increasing the susceptibility of incorporation with Ag-Au NPs. Our results showed that, Ag-Au NPs exhibited the highest antimicrobial performance against B. subtilis (14.30 mm ZOI) followed by E. coli (12.50 mm ZOI) and C. tropicalis (11.90 mm ZOI). In addition, Ag-Au NPs were able to inhibit the biofilm formation by 99.64%, 94.15%, and 90.79% against B. subtilis, E. coli, and C. tropicalis, respectively. Consequently, based on the promising properties, they showed superior antimicrobial potential at low concentration and continued-phase durability, they can be extensively-used in many pharmaceutical and biomedical applications.

Irradiation depolymerized guar gum as partial replacement of gum Arabic for microencapsulation of mint oil.

Spray dried microcapsules of mint oil were prepared using gum Arabic alone and its blends with radiation or enzymatically depolymerized guar gum as wall materials. Microcapsules were evaluated for retention of mint oil during 8-week storage during which qualitative changes in encapsulated mint oil was monitored using principal component analysis. The microcapsules with radiation depolymerized guar gum as wall material component could better retain major mint oil compounds such as menthol and isomenthol. The t(1/2) calculated for mint oil in microcapsules of gum Arabic, gum Arabic:radiation depolymerized guar gum (90:10), gum Arabic:enzyme depolymerized guar gum (90:10) was 25.66, 38.50, and 17.11 weeks, respectively. The results suggested a combination of radiation depolymerized guar gum and gum Arabic to show better retention of encapsulated flavour than gum Arabic alone as wall material.

Decontamination of gum arabic with gamma-rays or electron beams and effects of these treatments on the material.

Samples of gum arabic were irradiated to 2.5, 5.0 and 10.0 kGy with gamma-rays and electrons for a comparison of the relative effectiveness of these two treatments and for investigation of the effects of these doses of radiation on the material. The initial raw samples were contaminated with various strains of bacteria, including fungi and spore-forming bacteria (such as Enteroccus faecalis, Bacillus cereus and Closstridum perfringens). The samples were completely decontaminated by irradiation to 10.0 kGy with either gamma-rays or electrons. Slight changes in the physical properties of the material, such as darkening and viscosity decrease, were noticeable after irradiation to the highest dose, but not to the lower doses. A linear relationship between the absorbed dose and the material degradation was observed. gamma-rays were found to be more destructive than electrons. An optimal decontamination regimen for the material to be used in food industry and medicine would be irradiation to 5 kGy with electrons. It would be a safe alternative to the methods using hazardous chemicals, such as pesticides and fungicides. It would provide sufficient decontamination without adverse effects on the physical properties of the final products.