Nitrilotriacetic acid (NTA) is a well-knows ligand commonly used in commercially available resins for purifying proteins. On the other hand, tag-NTA conjugates are used for detecting polyhistidine-tagged proteins. NTA alkyne is an excellent azido-reactive building block that can be readily used to attach NTA groups to a biological substrate or a surface via the well-known click chemistry. Through the NTA moiety attached to the substrate or surface, genetically expressed proteins bearing the hexahistidine extension (HIS Tag) can be detected or immobilized via Ni-mediated His-Tag method. Immobilized metal affinity chromatography (IMAC) is a popular method for protein purification, particularly for recombinant proteins fused to a polyhistidine-tag. Transition metal ions immobilized to a matrix through a chelating ligand interact with the polyhistidine-tag, effectively sequestering the fused protein from a sample.