Preparation, Characterization and Toxicological Analysis of Alginate-phospholipid Vesicle Composite Hydrogels

Phospholipid vesicles were synthesized by thin-film dispersion. According to the electric double layer theory of micelles, the vesicles were stabilized by electrolyte solutions, including manganese chloride, calcium chloride and magnesium chloride. There are no significant changes in the particle sizes of the vesicles colloid by the additions of manganese chloride and calcium chloride solutions, respectively. However, the particle sizes of the vesicles were significantly bigger by adding a certain amount of magnesium chloride. To further increase the stability of the phospholipid vesicles, alginate-phospholipid vesical composite hydrogels were prepared by dropping sodium alginate(SA) solution into phospholipid vesicle colloids stabilized by manganese chloride, calcium chloride and magnesium chloride, respectively. The results show that magnesium chloride and SA hardly formed hydrogel, and calcium chloride and SA formed hydrogel much easier than manganese chloride did. The phosphatidylserine(PS) in the phospholipid vesicles bound to the Ca²⁺ and Mg²⁺ through forming PS-Ca²⁺, PS-Mg²⁺, respectively, however PS cannot interact with Mn²⁺, forming PS-Mn²⁺. The morphology, swelling ratio and cytotoxicity of the composite hydrogels made of alginate-phospholipid vesicles were characterized. The results show that a novel composite hydrogel could be prepared by calcium-crosslinking SA and the PS in the phospholipid vesicles colloid, forming stable and non-cytotoxic composite hydrogel.