This assay protocol outlines procedures for sample preparation and determination of mean size (effective diameter) of citrate stabilized colloidal gold nano-particles by high-resolution scanning electron microscope (SEM). The gold particles are three-dimensional structures and while most of them may be properly described as irregular, some possess certain distinct shapes. These may have more or less triangular, hexagonal and rectangular facets or spherical shapes. Some particles even have complex shapes such as diamonds and cylinders, and are clearly multi-faceted. SEM images are essentially two-dimensional projections of the non-spherical gold particles sitting on the Si substrate, which make the average size information somewhat ambiguous. However, by counting and measuring sufficiently large number of particles placed at random on the substrate, it is possible to arrive at the effective particle diameters.

• NCL_Method_PCC-15.pdf(PDF | 718 KB)

Researchers should cite this work as follows:

• Vladar, A., Ming, B. (2020). NIST - NCL Joint Assay Protocol, PCC-15. NCI Hub. doi:10.17917/NHEE-7838

  BibTex | EndNote

1. gold nanoparticles
2. SEM