Figure 1.
Gold nanoparticles synthesized by N. crassa extract at 60°C and pH 3 (A), pH 5.5 (B), and pH 10 (C). Insets: color change from before (yellow; left image) to after (red / purple; right image) incubation. D-F: Corresponding size distribution histograms of formed nanoparticles. G-H: HRTEM images of a quasi-spherical (G) and a hexagonal (H) gold nanoparticle with plane information. Gold nanoparticles synthesized by N. crassa extract at 60°C and pH 3 resulted in the formation of different shapes in a broad size range, incubation at 60°C and pH 5.5 results in the formation of mostly quasi-spherical particles and some different shapes, mainly triangles, with a main size range of 6 to 23 nm, and incubation at 60°C and pH 10 shows formation of quasi-spherical particles in a very small size range (3 to 12 nm).
Figure 2.
Representative EDS spectrum of synthesized gold nanoparticles. A: HADDF image of gold nanoparticles. B and C: lineal EDS spectrum.
Figure 3.
Raman spectra of MB (1), MB + fungal extract (2), MB + quasi-spherical AuNPs of 3 to 12 nm (3), MB + quasi-spherical AuNPs with some different shapes of 6 to 23 nm (4), and MB + different shaped gold nanoparticles with a broad size range (5).