Sodium alginate is a biomaterial that comes from brown algae. It is a polysaccaride that gels when it comes in contact with calcium. When combined with calcium chloride, CaCl2, the sugar molecules in the alginate clump together, like gum stuck in your hair. Alginate has many uses in the food industry, dentistry, and biomedical research. In the field of oncofertility, alginate is used to encapsulate follicles for in vitro maturation.