Jem 100cx tem

GNPs were prepared as previously described [19] , briefly, to 3 ml of laccase enzyme, containing 417 IU/mg, 0.1 ml of tetrachloroauric acid with concentration of (10 mg/1 ml) was added, (49% purity). The reaction mixture was stirred properly using magnetic stirrer, within 90 min the yellow colored solution started changing to pink then violet, detected visually and by UV/Visible spectrophotometer indicating the formation of GNPs. Average particle size and size distribution were determined by (PSS-NICOMP 380-ZLS) particle sizing system (St. Barbara, California, USA). UV/Visible Spectra of GNPs were recorded using a spectrophotometer (JASCO V-560UV/Vis, Japan) operated at a resolution of 1 nm from range of 200–700 nm and observed absorption peak at 550 nm due to excitation of surface plasmon vibration in GNPs solution or the SPR band. FT-IR measurements were carried out using a spectrophotometer (JASCO FT/IR-6300 infra-red) by employing KBr pellet technique. The size and morphology of synthesized GNPs were recorded using transmission electron microscope, TEM (JEM-100CX.TEM JEOL, Japan). TEM studies were carried by drop coating GNPs onto carbon-coated TEM grids. The film on the TEM grids were allowed to dry, the extra solution was removed using blotting paper.