Transdermal sequential delivery of functionalized Nano-Deep eutectic system for enhanced treatment of melanoma.

In the present study, we introduce the concept of "transdermal sequential delivery" as a non-invasive and synergistic approach for the treatment of melanoma. We developed a functionalized Deep Eutectic System (DES) that incorporates both small molecule drugs and nanoparticles. The glycolysis inhibitor 2-deoxy-D-glucose (2-DG) served as the Hydrogen Bond Donor (HBD) to form the DES, while glutathione (GSH)-responsive Mesoporous Organosilicon Nanoparticles (MON) were prepared and encapsulated with chlorin e6 (Ce6). These nanoparticles were incorporated into the DES through surface-modified citric acid (CA) as a linker, resulting in the functionalized 2-DG DES-MON@Ce6 system. By leveraging the skin's barrier properties and the permeation-enhancing effects of the DES, both 2-DG and MON@Ce6 were delivered to the melanoma tissue in a sequential manner. Initially, 2-DG mitigated hypoxia and the immunosuppressive tumor microenvironment (TME) by disrupting glycolysis, thereby creating favorable conditions for the subsequent photodynamic therapy (PDT) effects of MON@Ce6 and enhancing immunogenic cell death (ICD). Consequently, the 2-DG DES-MON@Ce6 system demonstrated significant anti-tumor activity against melanoma within the context of the "transdermal sequential delivery" strategy. Overall, our functionalized DES-nano system facilitates the sequential transdermal delivery of drugs to melanoma, thereby maximizing the combination anti-tumor efficacy through a cascade reaction.