Figure 2: Examples of the functional, reactive, labeling, and protective groups on dPEG® products. Quanta BioDesign offers functional and reactive groups with dPEG® linkers and spacers. These groups include maleimide, bromoacetyl, carboxylic acid, NHS esters, TFP esters, PFP esters, methoxy, hydroxy, thiol, amine, aminooxy, lipoamide, and tetrafluorophenyl azide groups. Quanta BioDesign’s click chemistry dPEG® products include azides, alkynes, and dibenzylcyclooctyne (DBCO) groups. Quanta BioDesign also makes and sells dPEG® products with labels such as biotin, 5(6)-carboxyfluorescein, and other labels. In addition, for radiolabeled dPEG® products, Quanta BioDesign sells DOTA-functionalized products. Finally, a number of dPEG® products are available with protective groups on one or both ends of the dPEG® linker or spacer. These protective groups include Fmoc, boc, CBZ, methoxytritylthiol, acetylthiol, phthalimide, phthalimidooxy, and tert-butyl ester groups.