Verma et al. Nanoscale Res Lett 2011, 6:16 http://www.nanoscalereslett.com/content/6/1/16 Page 5 of 7 Figure 4 The TEM images of gold nanotriangles synthesized by the reduction of 1 mM HAuCl4 by endophytic A. clavatus (a–b). The inset in (b) shows the histogram analysis for edge-to-edge length of the gold nanotriangles. The different types of edge/tip margins of gold nanotriangles were observed such as sharp-edged triangles (e, h), truncated triangles (c, f, g) and snipped triangles (d), (bar represent 100 nm for a and b, while 50 nm for c–h). increases. These observations confirm that as-formed gold nanoparticles are primarily dominated by [111] facets [22], which are quite consistent with the above electron diffrac- tion observation. AFM has been performed on the glass substrate in contact mode, for the two reaction mixture one of 48 h and another was 72 h incubation periods. The Figure 7b, d shows heterogeneous vertical and lateral dimensions since stacking defaults of gold nanotriangles takes place due to longer incubation of the reaction mix- ture. The three-dimensional images of these nanostructures 180 nm 140 nm 140-350 nm 20-40 nm Figure 5 Measurement of a relatively large, single-snipped gold nanotriangle shows a height of about 140 nm, while the edge length varies from 140–350 nm. Although several other triangles have much smaller dimensions then this one, which was also observed with AFM study. Figure 6 Representative XRD patterns of gold nanotriangles synthesized by the reaction of 1 mM aqueous HAuCl4 solution with endophytic A. clavatus biomass.