Zein spray-dried microparticles loaded with chemically modified curcumin for active wound healing

Wound healing is a delicate process comprising various phases, of which inflammation constitutes the most critical one, as some wounds fail to evolve from this state due to pre-existing pathologies or medical conditions, becoming chronic and causing pain and serious consequences for the patients. Given this context, innovative strategies able to support the body in the transition through the inflammatory and the proliferative phases are needed. Here, we propose to deliver to the wound zein microparticles (ZμP) loaded with chemically modified curcumin (mCUR), a novel bioactive molecule with strong antioxidant properties. Derived from the classic curcumin, mCUR chemical structure has been modified with an amino phenyl carbonyl group on C4 to overcome the poor bioavailability in the human body and to reach stronger inhibition of inflammatory markers thanks to a higher in vitro efficacy (lower IC50). ZμP were fabricated via spray drying starting from various zein/mCUR ratios. An exhaustive characterization of the physico-chemical properties of ZμP, either empty or loaded, has been carried out, alongside with bioactivity assessments via human keratinocytes and Escherichia coli cultures. All the formulations presented average diameters of 1 μm, resulted biocompatible, and led to an encapsulation efficiency in the range of 78.1–83.0 %. Finally, antioxidant properties of loaded microparticles were assessed via DCFH-DA assay, where a fluorescence decrease proportional to mCUR concentration was clearly visible (down to 41.7 %). These promising results highlight our formulations’ ability to reduce oxidative stress inside the cells, representing a promising strategy to address the problem of chronic wounds, supporting the body in overcoming the inflammatory stage.