Alginate is a natural water-soluble polysaccharide extracted from the cell walls of various brown algae. In fact, alginate is a linear block polymer of 1β-d-mannuronic acid (M) and α-l-guluronic acid (G). Among them, the content of M and G units affects its physical properties and determines its application. Alginic acid has the linear structure of a heteropolysaccharide obtained from brown algal cell walls. Alginic acid is available in the market as sodium alginate salt. As the carboxyl groups are located in their polymer chains, alginates are able to form gels in the presence of bipolar ions (calcium ions). Calcium alginate gels are commonly used in the development of wound dressings due to their porous structure and high absorption capacity for water. In addition, alginate salt beads are widely used for the controlled delivery of many cationic drugs and various growth factors. The drug loading and drug release rates of these alginates are influenced by ionic interactions between the drug and the alginate matrix. Polyelectrolyte complexes of alginate with other cationic polymers, such as chitosan, have also been extensively studied for cell encapsulation or as drug delivery matrices. CD Bioparticles offers amine, biotin and thiol modified alginates for drug development research.