Fabrication of alginate/chitosan nanocomposite sponges using green synthesized carbon dots as potential wound dressing

Sponges made with biopolymers have found great potential in biomedical applications due to their good biocompatibility, high flexibility, and extraordinary porosity. But some of their features still need to be improved. In this work, a new nanocomposite sponge with chitosan/alginate/carbon dots (CDs) is introduced. Using electrostatic interaction, calcium chloride as the crosslinking agent, glycerin as a plasticizer, and lyophilization method, alginate and chitosan were bonded with CDs to create these versatile nanocomposite sponges. The results showed that the addition of CDs to chitosan/alginate composite improved the water vapor transmission rate and mechanical properties of nanocomposite sponge. It also increased the porosity, water absorption rate, and hydrophilicity of the nanocomposite sponge which could absorb the moisture in the blood to increase blood concentration and viscosity, and become a semi-swelling viscous colloid to clog the capillaries. Cytocompatibility toxicity tests with L929 cells demonstrated that nanocomposite sponge caused no obvious cytotoxicity. The hemolytic rate of nanocomposite sponges indicates their suitable hemocompatibility. With increasing the concentration of CDs, the in vitro blood-clotting index decreases which indicates an increase in the hemostatic potential of nanocomposite sponges. The better hemostatic effect of nanocomposite sponge may be due to its ability to absorb blood platelets easily and to the higher liquid adsorption ratio. The obtained data encourage the use of this nanocomposite sponge for wound dressings.