Topical Lyophilized Targeted Lipid Nanoparticles in the Restoration of Skin Barrier Function following Burn Wound.

Lyophilized keratinocyte-targeted nanocarriers (TLN) loaded with locked nucleic acid (LNA) modified anti-miR were developed for topical application to full thickness burn injury. TLN were designed to selectively deliver LNA-anti-miR-107 to keratinocytes using the peptide sequence ASKAIQVFLLAG. TLN employed DOTAP/DODAP combination pH-responsive lipid components to improve endosomal escape. To minimize interference of clearance by non-targeted cells, especially immune cells in the acute wound microenvironment, surface charge was neutralized. Lyophilization was performed to extend the shelf life of the lipid nanoparticles (LNPs). Encapsulation efficiency of anti-miR in lyophilized TLN was estimated to be 96.54%. Cargo stability of lyophilized TLN was tested. After 9 days of loading with anti-miR-210, TLN was effective in lowering abundance of the hypoxamiR miR-210 in keratinocytes challenged with hypoxia. Keratinocyte uptake of DiD-labeled TLN was selective and exceeded 90% within 4 hr. Topical application of hydrogel-dispersed lyophilized TLN encapsulating LNA anti-miR-107 twice a week significantly accelerated wound closure and restoration of skin barrier function. TLN application depleted miR-107 and upregulated dicer expression, which accelerated differentiation of keratinocytes. Expression of junctional proteins such as claudin-1, loricrin, filaggrin, ZO-1, and ZO-2 were significantly upregulated following TLN treatment. These LNPs are promising as topical therapeutic agents in the management of burn injury.