Lipid nanoparticles are currently receiving increasing interest because they permit the
topical administration of
proteins, such as recombinant human
epidermal growth factor (rhEGF), in a sustained and effective manner. Because chronic
wounds have become a major healthcare burden, the
topical administration of rhEGF-loaded
lipid nanoparticles, namely solid
lipid nanoparticles (SLN) and nanostructured
lipid carries (NLC), appears to be an interesting and suitable strategy for the treatment of chronic
wounds. Both rhEGF-loaded
lipid nanoparticles were prepared through the emulsification-ultrasonication method; however, the NLC-rhEGF preparation did not require the use of any organic
solvents. The characterisation of the nanoparticles (NP) revealed that the encapsulation efficiency (EE) of NLC-rhEGF was significantly greater than obtained with SLN-rhEGF. The in vitro experiments demonstrated that gamma sterilisation is a suitable process for the final sterilisation because no loss in activity was observed after the sterilisation process. In addition, the proliferation assays revealed that the bioactivity of the nanoformulations was even higher than that of free rhEGF. Finally, the effectiveness of the rhEGF-loaded
lipid nanoparticles was assayed in a full-thickness
wound model in db/db mice. The data demonstrated that four
topical administrations of SLN-rhEGF and NLC-rhEGF significantly improved healing in terms of
wound closure, restoration of the inflammatory process, and re-epithelisation grade. In addition, the data did not reveal any differences in the in vivo effectiveness between the different rhEGF-loaded
lipid nanoparticles. Overall, these findings demonstrate the promising potential of rhEGF-loaded
lipid nanoparticles, particularly NLC-rhEGF, for the promotion of faster and more effective healing and suggest their future application for the treatment of chronic
wounds.