Antibiotic-resistant bacteria is a problem around the world. Silver nanoparticles (AgNPs) seem to be a potential candidate for development of new antimicrobial agents. In this study disc diffusion methods and PCR were used for phenotypic and molecular characterization of extended spectrum β-lactamase and carbapenemases producing E.coli and Klebsiella pneumonia clinical isolates. Antibacterial activity of chemically and green synthesized AgNPs were measured using micro broth dilution method, and genotoxicity of AgNPs was evaluated using Comet Assay. Molecular characterization revealed the dominance of CTX-M-15 and NDM-1 resistance genes. Both types of silver nanoparticles show a bactericidal effect against all isolates. The efficiency of green synthesized AgNPs was significantly better than chemically synthesized particles while bacterial DNA damage produced by chemically synthesized AgNPs was greater than green synthesized AgNPs. These results suggest the superiority of green synthesized AgNPs as a safer antibiotic alternative.

Due to the high mechanical properties, outstanding processing performance and biodegradable properties, ploylactic acid (PLA) attracted numerous studies in the past decades. Many reports indicated that PLA has high potential for high value added applications. Hydroxyapatite, Ca10(PO4)6(OH)2, has shown the osteoblast functions and bone bonding ability. It is an excellent material for biofunction scaffolds, drug delivery system and other biomedical applications. The major drawback of HA is the poor mechanical properties which inhibit its use. The initial aim of this present work was to study the mechanical performance of the nano-sized HA filled PLA composites. Different percentage of nano-HA was incorporated with PLA. The mechanical, thermal, morphological and thermodynamic properties of the nan0-compostes were investigated. The functional groups of n-HA and PLA were confirmed by Fourier transforms infrared spectroscopy. The morphological picture indicates due to the poor interfacial adhesion, many micro-cracks formed with the increase of HA content. However, due to the higher hardness and toughness of nano-sized HA, the tensile and flexural properties of the 5% HA incorporated PLA composites attained significant improvement. The final aim of this study is to reinforce this 5% nano-HA containing composite with phosphate glass fibres and study the mechanical and biological properties of this composite for potential biomedical application.