In this work, biocompatible gold nanoparticles were synthesized by reducing the chloroauric acid with ascorbic acid as a reducing agent. Colloidal gold nanoparticles were stabilized through nontoxic acacia gum sodium hydroxide .Synthesizing gold nano particle is confirmed by the change in color of chloroauric acid from yellow to ruby red and brown color depending on the stabilizers. The gold nanoparticles were characterized by UV-Visible spectrophotometer. Where the peak of the absorbance of surface plasmon resonance (SPR) was observed between the wave length 526 and 535 nm. The results of zeta potential were found in rang (-19, -40 mv), AFM and TEM images show two different shapes, hexagonal and spherical and the size of gold nanoparticles between 21.5nm and  29nm.

In the past years, various phytosynthetic processes have been utilised of silver nanoparticles for the low cost and environmentally friendly comparing to the chemical and physical methods. These unique metal nanoparticles are used in several applications which are including pharmaceuticals, antimicrobial and biomedical applications. Wherefore, the object of this work is biosynthesizing AgNPs from extracts of pineapple juice as reducing studying their characteristics by Ultraviolet-Visible (UV-vis) Spectrometer, Atomic Force Microscope (AFM), SEM Scanning Electron Microscope and Transmission Electron Microscope (TEM) The UV-Vis spectra results show a strong resonance centered on the surface of silver nanoparticles (AgNPs) at 410 nm. the presenting study is involved the preparation of (AgNPs) from natural source, which confirmed by UV-Visible spectral analysis in 410nm and the synergism effects with some antibiotic to increase the sensitivity to some pathogenic bacterial isolate as E. coli. In addition, our study is presented results of the minimum inhibitory concentration (MIC) that MIC for AgNPs is 25 while other antibiotics are (32,64,128). Finally, the synergism activity shows a significant difference in the sensitivity of some antibiotics used against E. coli bacteria, especially with levofloxacin and increased the inhibition form 419 mm to 1657.2 mm.

The research was focused on the production, characterization and application of Gold nanoparticles (AuNP s), which can be utilized in biomedical research and environmental cleaning applications.In vitro free radical scavenging activity of synthesized gold nanoparticles (AuNPs) was investigated. There are many studies use chemical method to synthesis gold nanoparticles (AuNPs) using various chemicals do as reducing agents at different conditions. In this study, gold nanoparticles (AuNPs)were synthesized by gel as reducing and stabilizing agent to reduce Au +3 ions form chloroauric acid (HAuCl 4 .3H 2 O) to nano gold .The reactionwere required heating around 60-80 o C.Synthesis of colloidal Au NPs was monitored by UV-Visible spectroscopy. The UV-Visible spectrum showed 524 nm , The characterization of the AuNPs such as their size , shape and stabile was performed by zeta potential , Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) techniques which indicated a size range of 14 to 25 nm. The in vitroantioxidant properties of AuNPs using DPPH assay have been evaluated and these nanoparticles were found to have