Biosynthesis of controllable size and shape gold nanoparticles by black seed (Nigella sativa) extract

We report on the use of black seed (Nigella sativa) extract, previously not exploited, in synthesis of gold nanoparticles. On treating aqueous chloroauric acid solution with black seed extract, the antioxidant activities critical roles of the various phytochemicals is observed leading to the formation of crystalline and poly shaped gold nanoparticles. In this research work, we developed a rapid and non-toxic method for the preparation of biocompatible gold nanoparticles by two different synthetic routes: microwave irradiation and thermo-induced procedures. The nanoparticles were characterized and investigated by ultraviolet-visible (UV-Vis) spectrophotometry, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD).The size and shape of the nanoparticles were found to be very sensitive to the quantity of the extract. As the amount of extract is increased, the stronger the interaction between the extract biomolecules and nascent nanoparticles, thus the yield of nanoparticles increased as shown by surface plasmon resonance bands in the UV-vis-NIR spectra. The reaction temperature has a significant role in production of gold nanoparticles with different shapes. The XRD studies reflect an interesting feature indicates that gold nanocrystals are highly anisotropic in nature, mainly triangular and hexagonal shapes, and that the particles are (111) oriented. The observed characteristics suggest the application of the biocompatible gold nanoparticles to future in vivo imaging and therapy.