Cisplatin is the first-line chemotherapeutic agent, but its systemic toxicity and side effects severely limit its clinical use. We report a microneedle technique to mediate the transdermal delivery of lipid-coated cisplatin nanoparticles (LCC-NPs) for efficient and safe cancer therapy. Cisplatin was encapsulated by tumor-targeting pH-responsive lipid nanoparticles with a high loading rate of 80%, and the encapsulation substantially increased the solubility of cisplatin and enhanced its antitumor efficiency in vitro. The LCC-NPs were embedded in dissolvable microneedles, and released from the microneedles after inserting into the skin. This enabled the nanoparticles to pass the stratum corneum for safe local delivery. An in vivo study with a xenograft tumor animal model demonstrated that microneedle arrays loaded with cisplatin nanoparticles significantly increased cytotoxicity and apoptosis in cancer cells with an apoptotic index of 58.6%, resulting in significantly reduced tumor volume and weight. Moreover, serum platinum, pulmonary toxicity, hepatotoxicity, and nephrotoxicity were not detected in vivo, indicating that this technique is biosafe. The cisplatin-nanoparticle microneedle system developed in this study may offer promising opportunities in cancer therapy for enhancing antitumor effects and reducing systemic toxicity and side effects.

The synergistic effects of immuno-chemotherapy delivered through a microneedle. aPD-1 blocks the binding of PD-L1 to PD-1, leading to the activation of T-cells. Intracellular release of CDDP induces direct cytotoxicity to the tumor cells.