In this work, copper nanoparticles (CuNPs) were synthesized by simple d laser Nd:YAG pulses in liquid at different parameters including laser wavelengths (λ= 1064 and 532 nm) and different pulses counts (400 and 500 pulses). The laser parameters have highly effect on the produced copper nanoparticles properties as follows: The XRD shows polycrystalline structure of Cu phase mixed with miner Cu2O phase. The crystallinity enhancement and increase the crystallite size for the CuNPs prepared using the 1064 nm laser compared with the 532 nm laser. The TEM test shows spherical copper NPs. The average diameters of spherical particles increased with increasing the pulses number and with using the 1064 nm laser. The EDX analysis shows the purity of the prepared samples with increasing the oxygen content for sample prepared using the 1064 nm laser. The UV-visible absorbance shows plasmon peak for CuNPs at about 620 nm, and has a red-shift corresponding to increasing the NPs size. Nanoparticles with smallest size has the highest antibacterial effect toward both E.coli and Staphylococcus-aureus bacteria. The antibacterial activity against E. coli better than Staphylococcus aureus due to their difference in cell wall. It seems increasing the NPs size using the fundamental wavelength (1064 nm) cause to reduce their effect compare with the 532 nm laser. The prepared copper nanoparticles are candidate for use as antibacterial agent instead of some antibiotic.
