Hydrogels developed as stimuli-responsive drug delivery systems (DDSs) are increasingly concerned research focus in many fields such as chemistry, functional materials and biomedicine. Herein, we report the fabrication, characterization and drug release property of new gelatin composite hydrogels by using biocompatible gelatin and the doxorubicin (DOX)-loaded micelles of a redox-responsive side-chain ferrocene (Fc)-containing amphiphilic diblock copolymer PNFc-b-PNTEG (Fig. 1). The self-assembly method was firstly adopted to prepare the DOX-loaded micelles of PNFc-b-PNTEG with oxidation-sensitive release property, and the DOX-loaded gelatin composite hydrogels were then successfully fabricated by using blending and soaking methods, respectively. The formed hydrogels were characterized by many techniques including scanning electron microscope, energy-dispersive spectroscopy, differential scanning calorimetry, thermogravimetry and swelling test. The successful encapsulation of the DOX-containing micelles in the gelatin matrix was demonstrated, and the prepared composite hydrogels exhibited improved thermal stability, faster swelling speed and higher swelling ratios. The oxidation-triggered controlled in vitro release of DOX from the composite hydrogels was confirmed by using FeCl3 at different concentrations as an oxidizing agent. The composite hydrogels could act as excellent solid carriers to guarantee the sustained-release effect of DOX, and it is feasible to keep the DOX molecules with high concentration at the specific site for a long period (20 days or so). Thus, the present composite hydrogels are anticipated to be good candidates as redox-responsive DDSs.

Chutong Shi, Li Zhang, Honglei Yin and Haibin Gu