Hydroxy-PEG3-SS-PEG3-alcohol contains two terminal hydroxyl groups and a cleavable disulfide bond. The disulfide bond can be cleaved via reduction reactions using Dithiothreitol (DTT) reagent. The hydroxyl groups can be reacted to further derivatize the compound. The hydrophilic PEG chains increase the water solubility of the compound in aqueous media. The water solubility properties of the PEG linker are enhanced with longer PEG chains.