Polysaccharides, such as alginates, are widely used in food, cosmetic and medical fields due to their structural properties, biocompatibility and safety. When alginate is combined with divalent cations a hydrogel is formed that exhibits a level of biocompatibility that can encapsulate cells [1]. Previous studies have shown that purity can affect the biocompatibility of alginate implants [2]. Alginate is a copolymer composed of mannuronate (M) and guluronate (G) stereomonomers [3, 4]. The affinity of a divalent cation (i.e. calcium) is stronger for G isomers due to the steric arrangement of the atoms [4, 5]. Two G monomers form an “egg-box” in which a calcium ion sits and crosslinks two polymer chains [4]. Consequently the M:G ratio will effect the crosslinking capacity and thus the physical properties of a calcium alginate gel