Sodium alginate rapidly forms a gel structure with the presence of divalent cations such as Ca2+, resulting in a highly compacted gel network [34].
Spherical gel particles of calcium alginate are often investigated and applied as a carrier of immobilized enzyme [35], a drug delivery capsule [36], a carrier of entrapped living cells [37-38], and a food supplement [39].
However, the formation of the alginate membrane has not been investigated as much.