Influence of gelatin on the functional characteristics and wound healing potential of chitosan/zein films loaded with ellagic acid nanoparticles

Biopolymers based-films are an alternative to conventional bandages as the occlusion and superficial properties, important for wound healing, are supplemented with the controlled release of active molecules. Chitosan/zein/gelatin films loaded with ellagic acid (EA) nanoparticles were designed as an antimicrobial bandage platform for wound treatment. The films were characterized in terms of morphology, thickness, sorption, solubility, contact angle and water vapor permeability. The phenyl rings of EA were found to interact transiently with the polymers, what could explain the resulting controlled release. All films containing gelatin showed a burst-effect in the first hour (>29%), followed by a sustained release along the next 24 h (>78%), releasing the residual content after the next 48–168 h, according to the formulation. The release curves adjusted to the first-order model. The EA-loaded films reduced the viability of Staphylococcus aureus and Candida albicans in 2 and 3 logs, respectively and were also found to inhibit Pseudomonas aeruginosa. They presented a tensile strength between 3.6 and 10.8 MPa and an elongation at break between 18.52 and 46.34% showing good elasticity and smooth surfaces, supporting their potential use as a skin layer device. In view of the most favorable results, the film F4, with equivalent proportions of CHI (27.8%) and gelatin (24.9%), was chosen for wound healing evaluation in vivo. This film accelerated the wound contraction, reduced the number of inflammatory cells in the injured tissue and did not cause any deformation in the healing process. Accordingly, this film was found a suitable dressing device and present great potential to be used as a bandaging material in the treatment of wounds.