2-(4-((bis((1-tert-butyl-1H-1,2,3-triazol-4-yl)methyl)amino)methyl)-1H-1,2,3-triazol-1-yl)acetic acid (BTTAA) is a novel, water-soluble accelerating ligand for CuAAC click reaction that provides much greater rate enhancement compared to previous generation ligands (e.g. THPTA or TBTA). BTTAA ligand performed best with ubiquitin Glu18AzFMore importantly, it minimizes perturbations to the physiological state of the cells or organisms probed and allows for effective bioconjugation with suppressed cell cytotoxicity by further lowering Cu loading in the catalyst formulation.
Increasing the Efficacy of Bioorthogonal Click Reactions for Bioconjugation: A Comparative Study.
Fast, Cell-Compatible Click Chemistry with Copper-Chelating Azides for Biomolecular Labeling. 
Lanthanide tags for site-specific ligation to an unnatural amino acid and generation of pseudocontact shifts in proteins. 
Monitoring Dynamic Glycosylation in Vivo Using Supersensitive Click Chemistry. 
Copper-catalyzed click reaction on/in live cells. 
A pH-activatable fluorescent aptamer probe for imaging of target cancer cells.