10 nm Ni-NTA-Nanogold®1 can be used to detect or localize 6xHistidine (His) or Poly-His tagged recombinant proteins withoutthe use of anti-His-tag antibodies in protein mixtures, multisubunit protein complexes, tissue or cell samples, using electronmicroscopy (EM), light microscopy, blots and plate-based assays. Using 10 nm Ni-NTA-Nanogold®, His-tagged recombinantproteins originating from a variety of expression vectors can be labeled under both non-denaturing and denaturing bufferconditions. The labeled His-tagged recombinant proteins can be detected by electron microscopy using low magnification,directly visualized as pink bands on western blots, or measured using a spectrophotometer in microplate assays without the useof gold or silver enhancement. 10 nm Ni-NTA-Nanogold® can also be used to identify His-tagged proteins containing eluentfractions from Immobilized Metal Affinity Chromatography (IMAC) procedures using a simple dot blot procedure.