Foamed microemulsion nanodroplets loaded with chlorin e6 for epidermal-targeted treatment against psoriasis

Psoriasis is a chronic skin disease characterized by the hyperproliferation of keratinocytes and an overactive autoimmune response. Photodynamic therapy (PDT) has been established as a promising intervention for alleviating psoriasis. However, the current transdermal delivery of photosensitizers is inefficient and imprecise. In this study, we developed a foamed microemulsion nanodroplets system containing chlorin e6 (Ce6 FM), exhibiting precise epidermal targeting and retention, which targeted the aberrantly proliferating epidermal cells at psoriatic skin lesions and avoided the damage to the normal cutaneous cells. Upon application in a psoriatic mouse model, Ce6 FM efficiently induced keratinocyte apoptosis by generating reactive oxygen species under laser. Furthermore, Ce6 FM-based PDT activated the cyclooxygenase-2-induced immunosuppressive pathway in keratinocytes, resulting in the amelioration of the autoimmune microenvironment in psoriatic skin. Additionally, Ce6 FM-based PDT did not induce skin damage or atrophy associated with non-targeted halometasone treatment. Overall, Ce6 FM-based PDT holds promise as an effective, safe and compliant strategy for psoriasis treatment.