Antibacterial gold nanoparticles-biomass assisted synthesis and characterization.

Xylose is a natural monosaccharide found in biomass such as straw, pecan shells, cottonseed hulls, and corncobs. Using this monosaccharide, we report the facile, green synthesis and characterization of stable xylose encapsulated gold nanoparticles (Xyl-GNPs) with potent antibacterial activity. Xyl-GNPs were synthesized using the reduction property of xylose in an aqueous solution containing choloraurate anions carried out at room temperature and atmospheric pressure. These nanoparticles were stable and near spherical in shape with an average diameter of 15 +/- 5 nm. Microbiological assay results showed the concentration dependent antibacterial activity of these particles against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus epidermidis) bacteria. Thus the facile, environmentally friendly Xyl-GNPs have many potential applications in chemical and biomedical industries, particularly in the development of antibacterial agents in the field of biomedicine.

Bactericidal activity of starch-encapsulated gold nanoparticles.

We report the bactericidal applications of eco-friendly starch encapsulated gold nanoparticles (St-AuNPs). The mechanism of interaction of the properly characterized St-AuNPs with both Gram negative and Gram positive bacteria were investigated using spread plate assay, transmission electron microscopy (TEM), and fluorescent propidium iodide (PI) exclusion assay. The St-AuNPs were found to possess significant dose dependent antibacterial activity against both types of bacteria. St-AuNPs at 1.2 mg/mL caused 98 % eradication of Gram positive bacteria that was exposed over a period of 12 h. Similarly, 4.8 mg/mL St-AuNPs caused 98 % eradication of Gram negative bacteria over a period of 12h. The St-AuNPs are biocompatible and present a useful solid porous carbohydrate-based polymer vehicle with excellent antimicrobial activity against [Frontiers in Bioscience 18, 982-992, June 1, 2013].

Size-dependent antimicrobial properties of sugar-encapsulated gold nanoparticles synthesized by a green method.

The antimicrobial properties of dextrose-encapsulated gold nanoparticles (dGNPs) with average diameters of 25, 60, and 120 nm (± 5) and synthesized by green chemistry principles were investigated against both Gram-negative and Gram-positive bacteria. Studies were performed involving the effect of dGNPs on the growth, morphology, and ultrastructural properties of bacteria. dGNPs were found to have significant dose-dependent antibacterial activity which was also proportional to their size. Experiments revealed the dGNPs to be bacteriostatic as well as bactericidal. The dGNPs exhibited their bactericidal action by disrupting the bacterial cell membrane which leads to the leakage of cytoplasmic content. The overall outcome of this study suggests that green-synthesized dGNPs hold promise as a potent antibacterial agent against a wide range of disease-causing bacteria by preventing and controlling possible infections or diseases.