A narrow bandgap Schottky heterojunction Fe 2 N/CeO 2 microneedle triggering sonodynamic reactive oxygen species storm for drug‐resistance‐free skin fungal infection

Abstract Sonodynamic therapy (SDT) using inorganic sonosensitizers provides precise, noninvasive treatment for skin fungal infections (SFIs) due to deep tissue penetration and biocompatibility. However, their application is limited by inherent‐wide bandgap, poor oxygen adsorption, and rapid charge recombination. Herein, we develop an iron nitride/cerium oxide (Fe 2 N/CeO 2 ) narrow‐bandgap Schottky heterojunction sonosensitizer embedded in microneedle (MN) patches (MN@Fe 2 N/CeO 2 ) for SFIs treatment. Theoretical and experimental studies have confirmed that fast electron transfer from metallic Fe 2 N to semiconductor CeO 2 drastically reduces the bandgap, boosts oxygen adsorption, and leads to a robust reactive oxygen species storm. Ultrasound‐induced MN@Fe 2 N/CeO 2 exhibits superior antifungal efficacy 1.50‐fold higher than that of ketoconazole cream in vivo with biocompatibility and no drug resistance. Transcriptome sequencing reveals that Candida albicans is eradicated through multiple pathways, including antioxidant stress. This study pioneers high‐performance SDT by integrating an advanced heterojunction design with practical MN delivery to enhance SFI treatment.