Carboxy-PEG4-phosphonic acid contains a carboxylic acid and phosphonic acid ends groups. The carboxylic acid can react with primary amines in the presence of activators such as EDC and DCC to form stable amide bonds. Phosphonic acid is used for surface modification. The hydrophilic PEG linker can increase the solubility of a compound in aqueous media and improve the hydrophilicity of the surfaces.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.