Alginate-based self-healing hydrogels assembled by dual cross-linking strategy: Fabrication and evaluation of mechanical properties

One way to enhance the poor mechanical properties of the self-healing hydrogels based on host-guest (HG) interaction is employing the dual cross-linking method. Here, the alginate-based hydrogels based on HG complexation were prepared through the modification of alginate (ALG) polysaccharide with beta-cyclodextrin (beta CD) and adamantane (Ad) as host and guest groups with different grafting values, respectively. The porous structure was confirmed for all ALG-CD:ALG-Ad hydrogels. The average pore size of ALG-CD1:ALG-Ad1 hydrogel cross-linked by HG interactions was 288 mu m. Mechanical properties of the alginate-based HG hydrogels were improved by incorporating Ca2+ ions in their structure through dual cross-linking methodology. The maximum modulus of the porous dual-crosslinked hydrogel was reached up to 6500 Pa. The healing time of less than 5 s was obtained for the alginate-based hydrogels. The fabricated hydrogels can be used in 3D printing, tissue en-gineering, and drug delivery systems due to their biocompatibility and shear-thinning behavior.