Phospholipid-PEG-Biotin (MW 1000 and MW 3400) is a derivative of a phospholipid and PEG, featuring a biotin moiety and a phospholipid connected via a linear PEG linker. This compound, particularly with a molecular weight of 3400, is capable of interacting with avidinylated antibodies. It finds applications in modifying the surface of liposomes, cells, and pancreatic islets, making it useful in cell transplantation [1] [2] [3].