[23] Carrier Potential of Glycoproteins

This chapter presents the practical details for glycoprotein-receptor systems that are being studied as drug carriers, primarily by endocytic routes. Glycoproteins have considerable potential for targeting molecules to cells when they are required to be deposited in the cell cytosol rather than in the lysosomal system. Normally this involves sequestration of the carried drug within a capsule through which it essentially cannot permeate. The capsule is then designed so that it can fuse with the surface of the target cell, depositing its contents within. The chapter discusses the use of viruses for encapsulating and delivering drugs, targeted by glycoproteins. The chapter discusses application in directing viral coats containing drugs. Some of the major cell surface receptors for glycoproteins are presented. Glycoproteins are relatively rare in the interior of cells, particularly in the cytosol. However, they are present to some extent on internal membranes, and they may be concerned with specific membrane-membrane interactions. Thus, by using a two-layered structure, investigators might exploit intracellular glycoprotein recognition to direct materials to particular organelles.