1.1.4 Carrageenan
Carrageenan is a negatively charged linear sulfur sugar acquired from algae such as Chondrus cripus , Gigartina stellate ,Hypnea , Halurus and Solieria (Prajapati et al., 2014). Carrageenan is made up of 3,6 anhydro galactopyranose and galactose linked by galactose α-1,3 and β -1, 4 glycosidic bonds. The residue 3, 6-anhyro-D-galactose is essential for forming gel by carrageenan (Venkatesan et al., 2015). Carrageenans are easily soluble in water, biocompatible, nontoxic, highly viscous, high gelling capacity and stable in a wide pH range. It exists in the form of nanoparticles, hydrogels, microspheres, nanofibers, wafers, films, pellets and microspheres and it has an application in tissue designing, drug transport, wound healing, pharmaceutical formulations, and biosensing (Pacheco-Quito et al., 2020).