Ald-PEG-Azide（Azide-PEG-Ald） is a compound that belongs to the class of polyethylene glycol (PEG) derivatives. PEG is a widely used polymer in various fields, including pharmaceuticals, due to its biocompatibility, low toxicity, and water solubility. Ald-PEG-Azide contains functional groups that make it particularly useful in pharmaceutical research and development. The azide group, for instance, is a valuable functional group in click chemistry, a technique used to synthesize and modify biomolecules. Click chemistry allows researchers to attach small molecules, such as drugs, to biomolecules, such as proteins or DNA, with high specificity and efficiency. Ald-PEG-Azide is often used as a linker or spacer molecule to connect drugs to biomolecules, improving their solubility, stability, and bioavailability. Therefore, Ald-PEG-Azide is a versatile compound that has great potential in drug discovery, drug delivery, and imaging applications.