A Multifunctional Rocket‐Like Microneedle System with Thrusters for Self‐Promoted Deep Drug Penetration and Combination Treatment in Melanoma.

Photodynamic therapy (PDT) proves highly effective in addressing melanoma, and its synergy with targeted therapy offers a promising avenue in tumor treatment. However, the therapeutic outcome is largely impeded by the challenge of current photosensitizers and targeted drugs in reaching deep tumor tissues. Herein, a dually‐layered "microneedle rocket" termed PcNP/TRA‐HA‐Tyr/CLG‐MN is designed. The upper layer of the microneedle (MN) is composed of photodynamically active mesoporous silica nanoparticles, featuring photosensitizers covalently bonded to them. Within the mesopores of these nanoparticles lies trametinib (TRA), a compound that specifically targets the hyperactive MEK pathway present in melanoma cells. The lower layer is composed of an enzyme‐mediated hyaluronic acid‐tyramine hydrogel (HA‐Tyr/CLG) with collagenase (CLG), serving as rocket thrusters for remodeling the extracellular matrix (ECM) in tumor microenvironment. Among the three types of MNs prepared, the PcNP/TRA‐HA‐Tyr(II)/CLG‐MN exhibits the deepest penetration in tumor tissues and the longest retention time in vivo. Notably, the administrations of PcNP/TRA‐HA‐Tyr(II)/CLG‐MN alongside light irradiation significantly suppress the growth of A375‐xenografted tumors in mice. Together, the strategy of combining mesoporous silica nanoparticles, enzymatically cross‐linked hydrogels and CLG‐mediated ECM remodeling enables deep drug penetration and efficacious combination treatment against melanoma, showcasing significant potential in the realm of cancer nanomedicine. [ABSTRACT FROM AUTHOR]