Colloidal gold is very attractive for several applications in biotechnology because of its unique physical and chemical properties. Many different synthesis methods have been developed to generate gold nanoparticles (AuNPs). Here, we will introduce these methods and discuss the differences between fabrication techniques. We will also discuss ecofriendly synthesis methods being developed to efficiently generate AuNPs without the use of toxic substrates. Finally, we will discuss the medical applications for AuNPs by highlighting the potential use of intact or functionalized AuNPs in combating bacterial infections.

This article reviews some of the recent biological applications of gold nanoparticles (GNPs) which have been discovered lately by individual studies all around the world. GNPs have emerged as a promising candidates for various biological applications due to their unique physical properties (size and shape dependent), excellent biocompatibility, facile synthesis, ease of bioconjugation, etc. This review starts with a brief introduction about nanotechnology followed by an insight into the history, emergence, and enhanced properties of various gold nanostructures, which form the basis for their numerous biomedical applications. In addition, a brief overview on some of the commonly used fabrication techniques for synthesizing GNPs is also discussed. Finally, a miscellany of the latest biological applications of GNPs, such as cancer diagnostics and therapy, biological probes, drug delivery, gene delivery, vaccine preparation, brain implants, artificial skin, sterilization system, and improving electrical signaling in the heart, published in different articles in reputed journals are highlighted.

Ring closure reactions O 0130Synthesis and QSAR Studies of Thiosemicarbazides, 1,2,4-Triazoles, 1,3,4-Thiadiazoles and 1,3,4-Oxadiazoles Derivatives as Potential Antibacterial Agents. -A series of title compounds of type (I)-(V) is prepared and screened for antibacterial activities. The results are discussed on the basis of QSAR calculations. -(DESAI*, N. C.; BHAVSAR, A. M.; SHAH, M. D.; SAXENA, A. K.; Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem. 47 (2008) 4, 579-585; Med. Chem. Div., Dep. Chem., Bhavnagar Univ., Bhavnagar 364 002, India; Eng.) -M. Bohle 33-036

Ring closure reactions O 0130Synthesis and QSAR Studies of 4-Oxo-thiazolidines and 2-Oxo-azetidines as Potential Antibacterial Agents. -Compared to the standard drug ciprofloxacin, products of type (III) and (V) exhibit moderate to good activity against Gram-positive and Gram-negative bacteria. -(DESAI*, N. C.; SHAH, M. D.; BHAVSAR, A. M.; SAXENA, A. K.; Indian J.

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.