Injectable and self-healing double network polysaccharide hydrogel as a minimally-invasive delivery platform

Injectable hydrogels exhibiting self-healing ability are promising carriers for controlled and sustained delivery in a minimally-invasive format for biomedical applications. We designed a polysaccharide-based double network hydrogel by mixing solutions of aldehyde-alginate (aAlg) and acrylic acid-chitosan (aCS) in the presence of adipic acid dihydrazide and FeCl₂ that resulted in dual crosslinking mediated by Schiff base and ionic interactions. The hydrogel exhibited excellent thixotropic and self-healing properties with a high compressive fracture strength of ≈ 48 kPa. Encapsulated cells were viable within the hydrogel, and after their release from the degraded gel. The controlled release of Doxorubicin and Ciprofloxacin from the hydrogels established the gel as a delivery platform. The released drugs were effective in killing cancer cells or arresting the growth of both bacteria. This work presents a self-healing and injectable degradable hydrogel that may be used as a minimally-invasive platform for the delivery of drugs and cells.