This invention relates to transduction of cargo molecules into living cells, such as protein transduction, in particular a delivery molecule for transduction of a cargo into a cell comprising: a cargo-binding molecule and/or a cargo; a glycosaminoglycan (GAG) binding element, which is capable of binding to GAG on the surface of the cell; and a protein transduction domain. Methods of transduction, methods of producing or modifying cargo for transduction, delivery molecules for transduction and methods of treatment using transduction, or using transduced cells are also provided.