Heparin is a highly sulfated, heterogeneous linear glycosaminoglycan with a relative molecular mass of 2 000-40 000. The biggest obstacle facing the clinical application of biomedical materials is their biocompatibility (including histocompatibility and hemocompatibility). Endothelial cells in contact with blood secrete heparan sulfate to prevent blood from clotting as it circulates through the body. Contact between medical polymer materials and blood can cause coagulation reactions, which can affect the performance of medical devices. The use of heparin to functionalize medical polymer materials through physical adsorption and chemical (including covalent and ionic bonding) binding can significantly improve their blood compatibility. This process is called heparinization, which refers to the immobilization of heparin molecules on biological materials. In addition, heparin can also be used to construct drug-loading systems to improve the biological activity and half-life of biopharmaceuticals and hydrophobic drugs. Therefore, heparin is an excellent drug carrier candidate or nanoparticle modifier in the drug development process. CD Bioparticles offers amine, biotin and thiol modified heparins for drug development research.