Carbohydrates are biomolecules that are involved in a range of biological processes and play key roles in, for instance, host immune response and cellular adhesion. Accordingly, functionalisation of medical devices such as stents, valves, catheters, prostheses and other devices for in vivoimplantation with carbohydrates is an area in which considerable interest is developing. Disclosed herein are surfaces having carbohydrates immobilised thereon. The carbohydrate has a linker moiety covalently bound thereto and the linker moiety has a carbon atom that forms a covalent bond with an atom on the target surface. The carbon based bond is a strong, non-hydrolysable covalent bond. Diazonium salts are utilised to produce the functionalised surfaces and they are particularly advantageous as they result in non-toxic readily escapable by-products
