Single Step, Antibiotic Mediated Synthesis of Gold Nanoparticles with Potent Antimicrobial Activity

Gentamicin is an aminoglycoside antibiotic with bactericidal activity that works through binding the 30S subunit of the bacterial ribosome, interrupting protein synthesis. In this study we synthesized Gentamicin capped gold nanoparticles (GNP’s) through a single step process in an aqueous buffer. The GNPs were identified and size was determined with transmission electron microscopy. The average diameter of the particles is 50 +/- 10 nm. Further characterization was carried out with UV/vis spectrophotometer, Electron dispersion spectroscopy (EDS) and FTIR analysis. Elemental composition of GNP’s was determined with EDS. Different antibacterial tests such as Turbidimetry, Spread plate assay, Tetrazolium salt based colorimetric assay and Micro-dilution Alamar blue assays were carried out on both Gram-negative and Gram-positive bacteria to determine the minimum inhibitory concentration of GNP’s. Bacterial cross sectioning was performed, to document the morphological changes on bacteria caused by GNP’s treatment. GNP’s activity was further confirmed with propidium iodide assay. Compared with the concentration of the Gentamicin alone, the Gentamicin gold nanoparticles have yielded a lower minimum inhibitory concentration, indicative of their success