Magnetic and self-healing chitosan-alginate hydrogel encapsulated gelatin microspheres via covalent cross-linking for drug delivery

In order to broaden the abilities of injectable hydrogel scaffolds, a self-healing chitosan/alginate hydrogel encapsulated with magnetic gelatin microspheres (MGMs) was prepared for anti-cancer drug delivery and soft tissue engineering. The hydrogel was formulated by cross-linking carboxyethyl chitosan (CEC) and oxidized alginate (OAlg) via the Schiff-base reaction. To strengthen the mechanical and biological capabilities of hydrogel, MGMs containing 5-fluorouracil (5-Fu) were prepared by an emulsion cross-linking method. In vitro gelation time, swelling ratio, degradation, compressive modulus and rheological behaviors were tested to monitor the effect of MGMs on the CEC-OAlg hydrogel. With a concentration of 30 mg/mL MGMs, the composite hydrogel provided with the suitable performance and showed excellent self-healing ability under physiological condition. Moreover, this composite hydrogel showed the sustained in vitro drug release compared with control MGMs and CEC-OAlg hydrogel. Our results demonstrated that this magnetic and self-healing CEC-OAlg hydrogel scaffold encapsulated MGMs containing 5-Fu was expected to be a platform for drug delivery and soft tissue engineering.