Synthesis of alginate stabilized gold nanoparticles by γ-irradiation with controllable size using different Au3+ concentration and seed particles enlargement

Gold nanoparticles with pre-selected size in the range 5–40 nm were synthesized by γ-irradiation of Au3+ solution containing natural polysaccharide alginate as a stabilizer. The gold nanoparticles with controllable size were prepared by two approaches: (i) varying the concentration of Au3+ from 0.25 to 1 mM and alginate from 0.25% to 1% (w/v) and (ii) enlargement of seed particles with double size from 20 to 40 nm at [Au3+]/[Au0]=6. The obtained gold nanoparticles were characterized by UV–vis spectroscopy and transmission electron microscopy. The results indicated that γ-irradiation method is suitable for production of gold nanoparticles with controllable size and high purity.